Publication Search Results

ID: 159268
Type: article
Authors: Addison, Brett C.; Wright, Duncan J.; Nicholson, Belinda A.; Cale, Bryson; Mocnik, Teo; Huber, Daniel; Plavchan, Peter; Wittenmyer, Robert A.; Vanderburg, Andrew; Chaplin, William J.; Chontos, Ashley; Clark, Jake T.; Eastman, Jason D.; Ziegler, Carl; Brahm, Rafael; Carter, Bradley D.; Clerte, Mathieu; Espinoza, Néstor; Horner, Jonathan; Bentley, John; Jordán, Andrés; Kane, Stephen R.; Kielkopf, John F.; Laychock, Emilie; Mengel, Matthew W.; Okumura, Jack; Stassun, Keivan G.; Bedding, Timothy R.; Bowler, Brendan P.; Burnelis, Andrius; Blanco-Cuaresma, Sergi; Collins, Michaela; Crossfield, Ian; Davis, Allen B.; Evensberget, Dag; Heitzmann, Alexis; Howell, Steve B.; Law, Nicholas; Mann, Andrew W.; Marsden, Stephen C.; Matson, Rachel A.; O'Connor, James H.; Shporer, Avi; Stevens, Catherine; Tinney, C. G.; Tylor, Christopher; Wang, Songhu; Zhang, Hui; Henning, Thomas; Kossakowski, Diana; Ricker, George; Sarkis, Paula; Schlecker, Martin; Torres, Pascal; Vanderspek, Roland; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Mireles, Ismael; Rowden, Pam; Pepper, Joshua; Daylan, Tansu; Schlieder, Joshua E.; Collins, Karen A.; Collins, Kevin I.; Tan, Thiam-Guan; Ball, Warrick H.; Basu, Sarbani; Buzasi, Derek L.; Campante, Tiago L.; Corsaro, Enrico; González-Cuesta, L.; Davies, Guy R.; de Almeida, Leandro; Do Nascimento, Jose-Dias, Jr.; García, Rafael A.; Guo, Zhao; Handberg, Rasmus; Hekker, Saskia; Hey, Daniel R.; Kallinger, Thomas; Kawaler, Steven D.; Kayhan, Cenk; Kuszlewicz, James S.; Lund, Mikkel N.; Lyttle, Alexander; Mathur, Savita; Miglio, Andrea; Mosser, Benoit; Nielsen, Martin B.; Serenelli, Aldo M.; Aguirre, Victor Silva; Themeßl, Nathalie
Abstract: We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the MINERVA-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of M_P = 0.138 ± 0.023 $\rm {M_J}$ (43.9 ± 7.3 $\, M_{\rm \oplus}$ ), a radius of R_P = 0.639 ± 0.013 $\rm {R_J}$ (7.16 ± 0.15 $\, \mathrm{ R}_{\rm \oplus}$ ), bulk density of $0.65^{+0.12}_{-0.11}$ (cgs), and period $18.38818^{+0.00085}_{-0.00084}$ $\rm {days}$ . TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M_* = 1.390 ± 0.046 $\rm {M_{sun}}$ , R_* = 1.888 ± 0.033 $\rm {R_{sun}}$ , T_eff = 6075 ± 90 $\rm {K}$ , and vsin i = 11.3 ± 0.5 km s^-1. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a ∼71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (∼100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems.

ID: 159315
Type: article
Authors: Flor-Torres, L. M.; Coziol, R.; Schröder, K. -P; Jack, D.; Schmitt, J. H. M. M.; Blanco-Cuaresma, Sergi
Abstract: In search for a connection between the formation of stars and the formation of planets, a new semi-automatic spectral analysis method using iSpec was developed for the TIGRE telescope installed in Guanajuato, Mexico. TIGRE is a 1.2m robotic telescope, equipped with an Echelle spectrograph (HEROS), with a resolution R ≃ 20000. iSpec is a synthetic spectral fitting program for stars that allows to determine in an homogeneous way their fundamental parameters: effective temperature, T_eff, surface gravity, log g, metallicities, [M/H] and [Fe/H], and rotational velocity, V sin i. In this first article we test our method by analysing the spectra of 46 stars, hosts of exoplanets, obtained with the TIGRE.

ID: 156374
Type: article
Authors: Bolmont, E.; Demory, B. -O; Blanco-Cuaresma, Sergi; Agol, E.; Grimm, S. L.; Auclair-Desrotour, P.; Selsis, F.; Leleu, A.
Abstract: Transit timing variations (TTVs) can be a very efficient way of constraining masses and eccentricities of multi-planet systems. Recent measurements of the TTVs of TRAPPIST-1 have led to an estimate of the masses of the planets, enabling an estimate of their densities and their water content. A recent TTV analysis using data obtained in the past two years yields a 34 and 13% increase in mass for TRAPPIST-1b and c, respectively. In most studies to date, a Newtonian N-body model is used to fit the masses of the planets, while sometimes general relativity is accounted for. Using the Posidonius N-body code, in this paper we show that in the case of the TRAPPIST-1 system, non-Newtonian effects might also be relevant to correctly model the dynamics of the system and the resulting TTVs. In particular, using standard values of the tidal Love number k₂ (accounting for the tidal deformation) and the fluid Love number k_2f (accounting for the rotational flattening) leads to differences in the TTVs of TRAPPIST-1b and c that are similar to the differences caused by general relativity. We also show that relaxing the values of tidal Love number k₂ and the fluid Love number k_2f can lead to TTVs which differ by as much as a few 10 s on a 3-4-yr timescale, which is a potentially observable level. The high values of the Love numbers needed to reach observable levels for the TTVs could be achieved for planets with a liquid ocean, which if detected might then be interpreted as a sign that TRAPPIST-1b and TRAPPIST-1c could have a liquid magma ocean. For TRAPPIST-1 and similar systems the models to fit the TTVs should potentially account for general relativity, for the tidal deformation of the planets, for the rotational deformation of the planets, and to a lesser extent for the rotational deformation of the star, which would add up to 7 × 2 + 1 = 15 additional free parameters in the case of TRAPPIST-1.

ID: 156465
Type: article
Authors: Casamiquela, L.; Tarricq, Y.; Soubiran, C.; Blanco-Cuaresma, Sergi; Jofré, P.; Heiter, U.; Tucci Maia, M.
Abstract: Context. Well studied open clusters (OCs) of the solar neighborhood are frequently used as reference objects to test galactic and stellar theories. For that purpose, their chemical composition needs to be known with a high level of confidence. It is also important to clarify if each OC is chemically homogeneous and if it has a unique chemical signature. Aims: The aims of this work are (1) to determine accurate and precise abundances of 22 chemical species (from Na to Eu) in the Hyades, Praesepe, and Rupecht 147 by using a large number of stars at different evolutionary states, (2) to evaluate the level of chemical homogeneity of these OCs, and (3) to compare their chemical signatures. Methods: We gathered ∼800 high resolution and high signal-to-noise spectra of ∼100 members in the three clusters, which were obtained with the latest memberships based on Gaia DR2 data. We built a pipeline, which computes atmospheric parameters and strictly line-by-line differential abundances among twin stars in our sample. With this method, we were able to reach a very high precision in the abundances (0.01-0.02 dex in most of the elements). Results: We find large differences in the absolute abundances in some elements, which can be attributed to diffusion, non-local thermodynamic equilibrium (non-LTE) effects, or systematics in the analysis. For the three OCs, we find strong correlations in the differential abundances between different pairs of elements. According to our experiment with synthetic data, this can be explained by some level of chemical inhomogeneity. We compare differential abundances of several stars from the Hyades and Praesepe tails: The stars that differ more in chemical abundances also have distinct kinematics, even though they have been identified as members of the tail. Conclusions: It is possible to obtain high precision abundances using a differential analysis even when mixing spectra from different instruments. With this technique, we find that the Hyades and Preasepe have the same chemical signature when G dwarfs and K giants are considered. Despite a certain level of inhomogeneity in each cluster, it is still possible to clearly distinguish the chemical signature of the older cluster Ruprecht 147 when compared to the Hyades and Praesepe. Full Tables 2, A.1-A.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz- bin/cat/J/A+A/635/A8 Thanks to observations at Telescope Bernard Lyot and data retrieved from the archives: ESO, TNG, FIES, ELODIE, ESPaDOnS and NARVAL.

ID: 158788
Type: article
Authors: Gaia Collaboration; Helmi, A.; van Leeuwen, F.; McMillan, P. J.; Massari, D.; Antoja, T.; Robin, A. C.; Lindegren, L.; Bastian, U.; Arenou, F.; Babusiaux, C.; Biermann, M.; Breddels, M. A.; Hobbs, D.; Jordi, C.; Pancino, E.; Reylé, C.; Veljanoski, J.; Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; Bailer-Jones, C. A. L.; Evans, D. W.; Eyer, L.; Jansen, F.; Klioner, S. A.; Lammers, U.; Luri, X.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Walton, N. A.; Cropper, M.; Drimmel, R.; Katz, D.; Lattanzi, M. G.; Bakker, J.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Holl, B.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Panuzzo, P.; Portell, J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Teyssier, D.; Altmann, M.; Andrae, R.; Audard, M.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Burgess, P.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Clotet, M.; Creevey, O.; Davidson, M.; De Ridder, J.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Fernández-Hernández, J.; Fouesneau, M.; Frémat, Y.; Galluccio, L.; García-Torres, M.; González-Núñez, J.; González-Vidal, J. J.; Gosset, E.; Guy, L. P.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hernández, J.; Hestroffer, D.; Hodgkin, S. T.; Hutton, A.; Jasniewicz, G.; Jean-Antoine-Piccolo, A.; Jordan, S.; Korn, A. J.; Krone-Martins, A.; Lanzafame, A. C.; Lebzelter, T.; Löffler, W.; Manteiga, M.; Marrese, P. M.; Martín-Fleitas, J. M.; Moitinho, A.; Mora, A.; Muinonen, K.; Osinde, J.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Richards, P. J.; Rimoldini, L.; Sarro, L. M.; Siopis, C.; Smith, M.; Sozzetti, A.; Süveges, M.; Torra, J.; van Reeven, W.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aerts, C.; Altavilla, G.; Álvarez, M. A.; Alvarez, R.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Arcay, B.; Astraatmadja, T. L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Balm, P.; Barache, C.; Barata, C.; Barbato, D.; Barblan, F.; Barklem, P. S.; Barrado, D.; Barros, M.; Barstow, M. A.; Bartholomé Muñoz, S.; Bassilana, J. -L; Becciani, U.; Bellazzini, M.; Berihuete, A.; Bertone, S.; Bianchi, L.; Bienaymé, O.; Blanco-Cuaresma, Sergi; Boch, T.; Boeche, C.; Bombrun, A.; Borrachero, R.; Bossini, D.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Bramante, L.; Bressan, A.; Brouillet, N.; Brüsemeister, T.; Brugaletta, E.; Bucciarelli, B.; Burlacu, A.; Busonero, D.; Butkevich, A. G.; Buzzi, R.; Caffau, E.; Cancelliere, R.; Cannizzaro, G.; Cantat-Gaudin, T.; Carballo, R.; Carlucci, T.; Carrasco, J. M.; Casamiquela, L.; Castellani, M.; Castro-Ginard, A.; Charlot, P.; Chemin, L.; Chiavassa, A.; Cocozza, G.; Costigan, G.; Cowell, S.; Crifo, F.; Crosta, M.; Crowley, C.; Cuypers, J.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; de Laverny, P.; De Luise, F.; De March, R.; De Martino, D.; de Souza, R.; de Torres, A.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Di Matteo, P.; Diakite, S.; Diener, C.; Distefano, E.; Dolding, C.; Drazinos, P.; Durán, J.; Edvardsson, B.; Enke, H.; Eriksson, K.; Esquej, P.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernique, P.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fraile, E.; Fraser, M.; Frézouls, B.; Gai, M.; Galleti, S.; Garabato, D.; García-Sedano, F.; Garofalo, A.; Garralda, N.; Gavel, A.; Gavras, P.; Gerssen, J.; Geyer, R.; Giacobbe, P.; Gilmore, G.; Girona, S.; Giuffrida, G.; Glass, F.; Gomes, M.; Granvik, M.; Gueguen, A.; Guerrier, A.; Guiraud, J.; Gutiérrez-Sánchez, R.; Haigron, R.; Hatzidimitriou, D.; Hauser, M.; Haywood, M.; Heiter, U.; Heu, J.; Hilger, T.; Hofmann, W.; Holland, G.; Huckle, H. E.; Hypki, A.; Icardi, V.; Janßen, K.; Jevardat de Fombelle, G.; Jonker, P. G.; Juhász, Á. L.; Julbe, F.; Karampelas, A.; Kewley, A.; Klar, J.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, M.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Kostrzewa-Rutkowska, Z.; Koubsky, P.; Lambert, S.; Lanza, A. F.; Lasne, Y.; Lavigne, J. -B; Le Fustec, Y.; Le Poncin-Lafitte, C.; Lebreton, Y.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; López, M.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marinoni, S.; Marschalkó, G.; Marshall, D. J.; Martino, M.; Marton, G.; Mary, N.; Matijevic, G.; Mazeh, T.; Messina, S.; Michalik, D.; Millar, N. R.; Molina, D.; Molinaro, R.; Molnár, L.; Montegriffo, P.; Mor, R.; Morbidelli, R.; Morel, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Nelemans, G.; Nicastro, L.; Noval, L.; O'Mullane, W.; Ordénovic, C.; Ordóñez-Blanco, D.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Panahi, A.; Pawlak, M.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poggio, E.; Poujoulet, E.; Prša, A.; Pulone, L.; Racero, E.; Ragaini, S.; Rambaux, N.; Ramos-Lerate, M.; Regibo, S.; Riclet, F.; Ripepi, V.; Riva, A.; Rivard, A.; Rixon, G.; Roegiers, T.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sanna, N.; Santana-Ros, T.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Ségransan, D.; Shih, I. -C; Siltala, L.; Silva, A. F.; Smart, R. L.; Smith, K. W.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Teyssandier, P.; Thuillot, W.; Titarenko, A.; Torra Clotet, F.; Turon, C.; Ulla, A.; Utrilla, E.; Uzzi, S.; Vaillant, M.; Valentini, G.; Valette, V.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Vaschetto, M.; Vecchiato, A.; Viala, Y.; Vicente, D.; Vogt, S.; von Essen, C.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Wertz, O.; Wevers, T.; Wyrzykowski, L.; Yoldas, A.; Žerjal, M.; Ziaeepour, H.; Zorec, J.; Zschocke, S.; Zucker, S.; Zurbach, C.; Zwitter, T.

ID: 156893
Type: article
Authors: Gaia Collaboration; Helmi, A.; van Leeuwen, F.; McMillan, P. J.; Massari, D.; Antoja, T.; Robin, A. C.; Lindegren, L.; Bastian, U.; Arenou, F.; Babusiaux, C.; Biermann, M.; Breddels, M. A.; Hobbs, D.; Jordi, C.; Pancino, E.; Reylé, C.; Veljanoski, J.; Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; Bailer-Jones, C. A. L.; Evans, D. W.; Eyer, L.; Jansen, F.; Klioner, S. A.; Lammers, U.; Luri, X.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Walton, N. A.; Cropper, M.; Drimmel, R.; Katz, D.; Lattanzi, M. G.; Bakker, J.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Holl, B.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Panuzzo, P.; Portell, J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Teyssier, D.; Altmann, M.; Andrae, R.; Audard, M.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Burgess, P.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Clotet, M.; Creevey, O.; Davidson, M.; De Ridder, J.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Fernández-Hernández, J.; Fouesneau, M.; Frémat, Y.; Galluccio, L.; García-Torres, M.; González-Núñez, J.; González-Vidal, J. J.; Gosset, E.; Guy, L. P.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hernández, J.; Hestroffer, D.; Hodgkin, S. T.; Hutton, A.; Jasniewicz, G.; Jean-Antoine-Piccolo, A.; Jordan, S.; Korn, A. J.; Krone-Martins, A.; Lanzafame, A. C.; Lebzelter, T.; Löffler, W.; Manteiga, M.; Marrese, P. M.; Martín-Fleitas, J. M.; Moitinho, A.; Mora, A.; Muinonen, K.; Osinde, J.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Richards, P. J.; Rimoldini, L.; Sarro, L. M.; Siopis, C.; Smith, M.; Sozzetti, A.; Süveges, M.; Torra, J.; van Reeven, W.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aerts, C.; Altavilla, G.; Álvarez, M. A.; Alvarez, R.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Arcay, B.; Astraatmadja, T. L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Balm, P.; Barache, C.; Barata, C.; Barbato, D.; Barblan, F.; Barklem, P. S.; Barrado, D.; Barros, M.; Barstow, M. A.; Bartholomé Muñoz, S.; Bassilana, J. -L; Becciani, U.; Bellazzini, M.; Berihuete, A.; Bertone, S.; Bianchi, L.; Bienaymé, O.; Blanco-Cuaresma, Sergi; Boch, T.; Boeche, C.; Bombrun, A.; Borrachero, R.; Bossini, D.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Bramante, L.; Bressan, A.; Brouillet, N.; Brüsemeister, T.; Brugaletta, E.; Bucciarelli, B.; Burlacu, A.; Busonero, D.; Butkevich, A. G.; Buzzi, R.; Caffau, E.; Cancelliere, R.; Cannizzaro, G.; Cantat-Gaudin, T.; Carballo, R.; Carlucci, T.; Carrasco, J. M.; Casamiquela, L.; Castellani, M.; Castro-Ginard, A.; Charlot, P.; Chemin, L.; Chiavassa, A.; Cocozza, G.; Costigan, G.; Cowell, S.; Crifo, F.; Crosta, M.; Crowley, C.; Cuypers, J.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; de Laverny, P.; De Luise, F.; De March, R.; De Martino, D.; de Souza, R.; de Torres, A.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Di Matteo, P.; Diakite, S.; Diener, C.; Distefano, E.; Dolding, C.; Drazinos, P.; Durán, J.; Edvardsson, B.; Enke, H.; Eriksson, K.; Esquej, P.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernique, P.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fraile, E.; Fraser, M.; Frézouls, B.; Gai, M.; Galleti, S.; Garabato, D.; García-Sedano, F.; Garofalo, A.; Garralda, N.; Gavel, A.; Gavras, P.; Gerssen, J.; Geyer, R.; Giacobbe, P.; Gilmore, G.; Girona, S.; Giuffrida, G.; Glass, F.; Gomes, M.; Granvik, M.; Gueguen, A.; Guerrier, A.; Guiraud, J.; Gutiérrez-Sánchez, R.; Haigron, R.; Hatzidimitriou, D.; Hauser, M.; Haywood, M.; Heiter, U.; Heu, J.; Hilger, T.; Hofmann, W.; Holland, G.; Huckle, H. E.; Hypki, A.; Icardi, V.; Janßen, K.; Jevardat de Fombelle, G.; Jonker, P. G.; Juhász, Á. L.; Julbe, F.; Karampelas, A.; Kewley, A.; Klar, J.; Kochoska, A.; Kohley, R.; Kolenberg, Katrien; Kontizas, M.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Kostrzewa-Rutkowska, Z.; Koubsky, P.; Lambert, S.; Lanza, A. F.; Lasne, Y.; Lavigne, J. -B; Le Fustec, Y.; Le Poncin-Lafitte, C.; Lebreton, Y.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; López, M.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marinoni, S.; Marschalkó, G.; Marshall, D. J.; Martino, M.; Marton, G.; Mary, N.; Matijevič, G.; Mazeh, T.; Messina, S.; Michalik, D.; Millar, N. R.; Molina, D.; Molinaro, R.; Molnár, L.; Montegriffo, P.; Mor, R.; Morbidelli, R.; Morel, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Nelemans, G.; Nicastro, L.; Noval, L.; O'Mullane, W.; Ordénovic, C.; Ordóñez-Blanco, D.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Panahi, A.; Pawlak, M.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poggio, E.; Poujoulet, E.; Prša, A.; Pulone, L.; Racero, E.; Ragaini, S.; Rambaux, N.; Ramos-Lerate, M.; Regibo, S.; Riclet, F.; Ripepi, V.; Riva, A.; Rivard, A.; Rixon, G.; Roegiers, T.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sanna, N.; Santana-Ros, T.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Ségransan, D.; Shih, I. -C; Siltala, L.; Silva, A. F.; Smart, R. L.; Smith, K. W.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Teyssandier, P.; Thuillot, W.; Titarenko, A.; Torra Clotet, F.; Turon, C.; Ulla, A.; Utrilla, E.; Uzzi, S.; Vaillant, M.; Valentini, G.; Valette, V.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Vaschetto, M.; Vecchiato, A.; Viala, Y.; Vicente, D.; Vogt, S.; von Essen, C.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Wertz, O.; Wevems, T.; Wyrzykowski, Ł.; Yoldas, A.; Žerjal, M.; Ziaeepour, H.; Zorec, J.; Zschocke, S.; Zucker, S.; Zurbach, C.; Zwitter, T.

ID: 158239
Type: article
Authors: Sarmento, Pedro; Delgado Mena, Elisa; Rojas-Ayala, Bárbara; Blanco-Cuaresma, Sergi
Abstract: Context. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has observed the H-band spectra of over 200 000 stars with R ∼ 22 000.
Aims: The main motivation for this work is to test an alternative method to the standard APOGEE pipeline (APOGEE Stellar Parameter and Chemical Abundances Pipeline, ASPCAP) to derive parameters in the near-infrared for FGK dwarfs.
Methods: iSpec and Turbospectrum are used to generate synthetic spectra matching APOGEE observations and to determine the parameters through χ² minimization.
Results: We present spectroscopic parameters (T_eff, [M/H], log g, v_mic) for a sample of 3748 main-sequence and subgiant FGK stars, obtained from their APOGEE H-band spectra.
Conclusions: We compare our output parameters with the ones obtained with ASPCAP for the same stellar spectrum, and find that the values agree within the expected uncertainties. A comparison with the optical samples California Planet Survey, High Accuracy Radial Velocity Planet Searcher - Guaranteed Time Observations, and PASTEL is also available, and median differences below 10 K for T_eff and 0.2 dex for [M/H] are found. Reasons for these differences are explored. The full H-band line list, the line selection for the synthesis, and the synthesized spectra are available at the CDS, as are the calculated parameters and their estimated uncertainties.
The line list, line mask, and parameter table are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/636/A85

ID: 155690
Type: article
Authors: Wyrzykowski, Ł.; Mróz, P.; Rybicki, K. A.; Gromadzki, M.; Kołaczkowski, Z.; Zieliński, M.; Zieliński, P.; Britavskiy, N.; Gomboc, A.; Sokolovsky, K.; Hodgkin, S. T.; Abe, L.; Aldi, G. F.; AlMannaei, A.; Altavilla, G.; Al Qasim, A.; Anupama, G. C.; Awiphan, S.; Bachelet, E.; Bakıș, V.; Baker, S.; Bartlett, S.; Bendjoya, P.; Benson, K.; Bikmaev, I. F.; Birenbaum, G.; Blagorodnova, N.; Blanco-Cuaresma, Sergi; Boeva, S.; Bonanos, A. Z.; Bozza, V.; Bramich, D. M.; Bruni, I.; Burenin, R. A.; Burgaz, U.; Butterley, T.; Caines, H. E.; Caton, D. B.; Calchi Novati, S.; Carrasco, J. M.; Cassan, A.; Čepas, V.; Cropper, M.; Chruślińska, M.; Clementini, G.; Clerici, A.; Conti, D.; Conti, M.; Cross, S.; Cusano, F.; Damljanovic, G.; Dapergolas, A.; D'Ago, G.; de Bruijne, J. H. J.; Dennefeld, M.; Dhillon, V. S.; Dominik, M.; Dziedzic, J.; Erece, O.; Eselevich, M. V.; Esenoglu, H.; Eyer, L.; Figuera Jaimes, R.; Fossey, S. J.; Galeev, A. I.; Grebenev, S. A.; Gupta, A. C.; Gutaev, A. G.; Hallakoun, N.; Hamanowicz, A.; Han, C.; Handzlik, B.; Haislip, J. B.; Hanlon, L.; Hardy, L. K.; Harrison, D. L.; van Heerden, H. J.; Hoette, V. L.; Horne, K.; Hudec, R.; Hundertmark, M.; Ihanec, N.; Irtuganov, E. N.; Itoh, R.; Iwanek, P.; Jovanovic, M. D.; Janulis, R.; Jelínek, M.; Jensen, E.; Kaczmarek, Z.; Katz, D.; Khamitov, I. M.; Kilic, Y.; Klencki, J.; Kolb, U.; Kopacki, G.; Kouprianov, V. V.; Kruszyńska, K.; Kurowski, S.; Latev, G.; Lee, C. -H; Leonini, S.; Leto, G.; Lewis, F.; Li, Z.; Liakos, A.; Littlefair, S. P.; Lu, J.; Manser, C. J.; Mao, S.; Maoz, D.; Martin-Carrillo, A.; Marais, J. P.; Maskoliūnas, M.; Maund, J. R.; Meintjes, P. J.; Melnikov, S. S.; Ment, K.; Mikołajczyk, P.; Morrell, M.; Mowlavi, N.; Moździerski, D.; Murphy, D.; Nazarov, S.; Netzel, H.; Nesci, R.; Ngeow, C. -C; Norton, A. J.; Ofek, E. O.; Pakštienė, E.; Palaversa, L.; Pandey, A.; Paraskeva, E.; Pawlak, M.; Penny, M. T.; Penprase, B. E.; Piascik, A.; Prieto, J. L.; Qvam, J. K. T.; Ranc, C.; Rebassa-Mansergas, A.; Reichart, D. E.; Reig, P.; Rhodes, L.; Rivet, J. -P; Rixon, G.; Roberts, D.; Rosi, P.; Russell, D. M.; Zanmar Sanchez, R.; Scarpetta, G.; Seabroke, G.; Shappee, B. J.; Schmidt, R.; Shvartzvald, Y.; Sitek, M.; Skowron, J.; Śniegowska, M.; Snodgrass, C.; Soares, P. S.; van Soelen, B.; Spetsieri, Z. T.; Stankevičiūtė, A.; Steele, I. A.; Street, R. A.; Strobl, J.; Strubble, E.; Szegedi, H.; Tinjaca Ramirez, L. M.; Tomasella, L.; Tsapras, Y.; Vernet, D.; Villanueva, S.; Vince, O.; Wambsganss, J.; van der Westhuizen, I. P.; Wiersema, K.; Wium, D.; Wilson, R. W.; Yoldas, A.; Zhuchkov, R. Ya; Zhukov, D. G.; Zdanavičius, J.; Zoła, S.; Zubareva, A.
Abstract: Gaia16aye was a binary microlensing event discovered in the direction towards the northern Galactic disc and was one of the first microlensing events detected and alerted to by the Gaia space mission. Its light curve exhibited five distinct brightening episodes, reaching up to I = 12 mag, and it was covered in great detail with almost 25 000 data points gathered by a network of telescopes. We present the photometric and spectroscopic follow-up covering 500 days of the event evolution. We employed a full Keplerian binary orbit microlensing model combined with the motion of Earth and Gaia around the Sun to reproduce the complex light curve. The photometric data allowed us to solve the microlensing event entirely and to derive the complete and unique set of orbital parameters of the binary lensing system. We also report on the detection of the first-ever microlensing space-parallax between the Earth and Gaia located at L2. The properties of the binary system were derived from microlensing parameters, and we found that the system is composed of two main-sequence stars with masses 0.57 ± 0.05 M_☉ and 0.36 ± 0.03 M_☉ at 780 pc, with an orbital period of 2.88 years and an eccentricity of 0.30. We also predict the astrometric microlensing signal for this binary lens as it will be seen by Gaia as well as the radial velocity curve for the binary system. Events such as Gaia16aye indicate the potential for the microlensing method of probing the mass function of dark objects, including black holes, in directions other than that of the Galactic bulge. This case also emphasises the importance of long-term time-domain coordinated observations that can be made with a network of heterogeneous telescopes. Full Tables B.1-D.1 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz- bin/cat/J/A+A/633/A98

ID: 154540
Type: article
Authors: Casamiquela, L.; Blanco-Cuaresma, Sergi; Carrera, R.; Balaguer-Núñez, L.; Jordi, C.; Anders, F.; Chiappini, C.; Carbajo-Hijarrubia, J.; Aguado, D. S.; del Pino, A.; Díaz-Pérez, L.; Gallart, C.; Pancino, E.
Abstract: The study of open-cluster chemical abundances provides insights on stellar nucleosynthesis processes and on Galactic chemo-dynamical evolution. In this paper we present an extended abundance analysis of 10 species (Fe, Ni, Cr, V, Sc, Si, Ca, Ti, Mg, O) for red giant stars in 18 OCCASO clusters. This represents a homogeneous sample regarding the instrument features, method, line list and solar abundances from confirmed member stars. We perform an extensive comparison with previous results in the literature, and in particular with the Gaia FGK Benchmark stars Arcturus and μ-Leo. We investigate the dependence of [X/Fe] with metallicity, Galactocentric radius (6.5 kpc _{GC GC} and |z| obtained for clusters and for field stars.

ID: 155417
Type: article
Authors: Gaia Collaboration; Eyer, L.; Rimoldini, L.; Audard, M.; Anderson, R. I.; Nienartowicz, K.; Glass, F.; Marchal, O.; Grenon, M.; Mowlavi, N.; Holl, B.; Clementini, G.; Aerts, C.; Mazeh, T.; Evans, D. W.; Szabados, L.; Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; Babusiaux, C.; Bailer-Jones, C. A. L.; Biermann, M.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; van Leeuwen, F.; Walton, N. A.; Arenou, F.; Bastian, U.; Cropper, M.; Drimmel, R.; Katz, D.; Lattanzi, M. G.; Bakker, J.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Masana, E.; Messineo, R.; Panuzzo, P.; Portell, J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Teyssier, D.; Altmann, M.; Andrae, R.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Burgess, P.; Busso, G.; Carry, B.; Cellino, A.; Clotet, M.; Creevey, O.; Davidson, M.; De Ridder, J.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Fernández-Hernández, J.; Fouesneau, M.; Frémat, Y.; Galluccio, L.; García-Torres, M.; González-Núñez, J.; González-Vidal, J. J.; Gosset, E.; Guy, L. P.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hernández, J.; Hestroffer, D.; Hodgkin, S. T.; Hutton, A.; Jasniewicz, G.; Jean-Antoine-Piccolo, A.; Jordan, S.; Korn, A. J.; Krone-Martins, A.; Lanzafame, A. C.; Lebzelter, T.; Löffler, W.; Manteiga, M.; Marrese, P. M.; Martín-Fleitas, J. M.; Moitinho, A.; Mora, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Richards, P. J.; Robin, A. C.; Sarro, L. M.; Siopis, C.; Smith, M.; Sozzetti, A.; Süveges, M.; Torra, J.; van Reeven, W.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Altavilla, G.; Álvarez, M. A.; Alvarez, R.; Alves, J.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Arcay, B.; Astraatmadja, T. L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Balm, P.; Barache, C.; Barata, C.; Barbato, D.; Barblan, F.; Barklem, P. S.; Barrado, D.; Barros, M.; Barstow, M. A.; Bartholomé Muñoz, S.; Bassilana, J. -L; Becciani, U.; Bellazzini, M.; Berihuete, A.; Bertone, S.; Bianchi, L.; Bienaymé, O.; Blanco-Cuaresma, Sergi; Boch, T.; Boeche, C.; Bombrun, A.; Borrachero, R.; Bossini, D.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Bramante, L.; Breddels, M. A.; Bressan, A.; Brouillet, N.; Brüsemeister, T.; Brugaletta, E.; Bucciarelli, B.; Burlacu, A.; Busonero, D.; Butkevich, A. G.; Buzzi, R.; Caffau, E.; Cancelliere, R.; Cannizzaro, G.; Cantat-Gaudin, T.; Carballo, R.; Carlucci, T.; Carrasco, J. M.; Casamiquela, L.; Castellani, M.; Castro-Ginard, A.; Charlot, P.; Chemin, L.; Chiavassa, A.; Cocozza, G.; Costigan, G.; Cowell, S.; Crifo, F.; Crosta, M.; Crowley, C.; Cuypers, J.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; de Laverny, P.; De Luise, F.; De March, R.; De Martino, D.; de Souza, R.; de Torres, A.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Diakite, S.; Diener, C.; Distefano, E.; Dolding, C.; Drazinos, P.; Durán, J.; Edvardsson, B.; Enke, H.; Eriksson, K.; Esquej, P.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernique, P.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fraile, E.; Fraser, M.; Frézouls, B.; Gai, M.; Galleti, S.; Garabato, D.; García-Sedano, F.; Garofalo, A.; Garralda, N.; Gavel, A.; Gavras, P.; Gerssen, J.; Geyer, R.; Giacobbe, P.; Gilmore, G.; Girona, S.; Giuffrida, G.; Gomes, M.; Granvik, M.; Gueguen, A.; Guerrier, A.; Guiraud, J.; Gutiérrez-Sánchez, R.; Haigron, R.; Hatzidimitriou, D.; Hauser, M.; Haywood, M.; Heiter, U.; Helmi, A.; Heu, J.; Hilger, T.; Hobbs, D.; Hofmann, W.; Holland, G.; Huckle, H. E.; Hypki, A.; Icardi, V.; Janßen, K.; Jevardat de Fombelle, G.; Jonker, P. G.; Juhász, Á. L.; Julbe, F.; Karampelas, A.; Kewley, A.; Klar, J.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, M.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Kostrzewa-Rutkowska, Z.; Koubsky, P.; Lambert, S.; Lanza, A. F.; Lasne, Y.; Lavigne, J. -B; Le Fustec, Y.; Le Poncin-Lafitte, C.; Lebreton, Y.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; López, M.; Lorenz, D.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchant, J. M.; Marconi, M.; Marinoni, S.; Marschalkó, G.; Marshall, D. J.; Martino, M.; Marton, G.; Mary, N.; Massari, D.; Matijevič, G.; McMillan, P. J.; Messina, S.; Michalik, D.; Millar, N. R.; Molina, D.; Molinaro, R.; Molnár, L.; Montegriffo, P.; Mor, R.; Morbidelli, R.; Morel, T.; Morgenthaler, S.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Nelemans, G.; Nicastro, L.; Noval, L.; O'Mullane, W.; Ordénovic, C.; Ordóñez-Blanco, D.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Panahi, A.; Pawlak, M.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poggio, E.; Poujoulet, E.; Prša, A.; Pulone, L.; Racero, E.; Ragaini, S.; Rambaux, N.; Ramos-Lerate, M.; Regibo, S.; Reylé, C.; Riclet, F.; Ripepi, V.; Riva, A.; Rivard, A.; Rixon, G.; Roegiers, T.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sanna, N.; Santana-Ros, T.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Ségransan, D.; Shih, I. -C; Siltala, L.; Silva, A. F.; Smart, R. L.; Smith, K. W.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Surdej, J.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Teyssandier, P.; Thuillot, W.; Titarenko, A.; Torra Clotet, F.; Turon, C.; Ulla, A.; Utrilla, E.; Uzzi, S.; Vaillant, M.; Valentini, G.; Valette, V.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Vaschetto, M.; Vecchiato, A.; Veljanoski, J.; Viala, Y.; Vicente, D.; Vogt, S.; von Essen, C.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Wertz, O.; Wevers, T.; Wyrzykowski, Ł.; Yoldas, A.; Žerjal, M.; Ziaeepour, H.; Zorec, J.; Zschocke, S.; Zucker, S.; Zurbach, C.; Zwitter, T.
Abstract: Context. The ESA Gaia mission provides a unique time-domain survey for more than 1.6 billion sources with G ≲ 21 mag. Aims: We showcase stellar variability in the Galactic colour-absolute magnitude diagram (CaMD). We focus on pulsating, eruptive, and cataclysmic variables, as well as on stars that exhibit variability that is due to rotation and eclipses. Methods: We describe the locations of variable star classes, variable object fractions, and typical variability amplitudes throughout the CaMD and show how variability-related changes in colour and brightness induce "motions". To do this, we use 22 months of calibrated photometric, spectro-photometric, and astrometric Gaia data of stars with a significant parallax. To ensure that a large variety of variable star classes populate the CaMD, we crossmatched Gaia sources with known variable stars. We also used the statistics and variability detection modules of the Gaia variability pipeline. Corrections for interstellar extinction are not implemented in this article. Results: Gaia enables the first investigation of Galactic variable star populations in the CaMD on a similar, if not larger, scale as was previously done in the Magellanic Clouds. Although the observed colours are not corrected for reddening, distinct regions are visible in which variable stars occur. We determine variable star fractions to within the current detection thresholds of Gaia. Finally, we report the most complete description of variability-induced motion within the CaMD to date. Conclusions: Gaia enables novel insights into variability phenomena for an unprecedented number of stars, which will benefit the understanding of stellar astrophysics. The CaMD of Galactic variable stars provides crucial information on physical origins of variability in a way that has previously only been accessible for Galactic star clusters or external galaxies. Future Gaia data releases will enable significant improvements over this preview by providing longer time series, more accurate astrometry, and additional data types (time series BP and RP spectra, RVS spectra, and radial velocities), all for much larger samples of stars. A movie associated to Fig. 11 is available at http: //https://www.aanda.org.Data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz- bin/qcat?J/A+A/623/A110.

ID: 152894
Type: article
Authors: Zhou, Yutao; Yan, Hongliang; Shi, Jianrong; Blanco-Cuaresma, Sergi; Gao, Qi; Pan, K.; Xu, Xiaodong; Zhang, Junbo; Zhao, Gang
Abstract: The discovery of Li-rich giants has introduced a new challenge for standard stellar evolution models. To resolve this issue, the number of this type of object has been rapidly increased through the development of worldwide surveys. Taking advantage of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey, 44 new Li-rich giants are reported, which are confirmed with high-resolution observations. Based on the high-resolution and high signal-to-noise spectra, we derived the atmospheric parameters and elemental abundances with the spectral synthesis method. We performed a detailed analysis of their evolutionary stages, infrared excess, projected rotational velocity (v\sin i), and stellar population. We find that (1) the Li-rich giants concentrate at the evolutionary status of the red giant branch bump, red clump, and asymptotic giant branch; (2) three of them are fast rotators and none exhibit infrared excess. Our results imply that the origins of Li enrichment are most likely to be associated with the extra mixing in the stellar interior, and the external sources might only make a minor contribution. Moreover, various Li-rich episodes take place at different evolutionary stages.

ID: 149010
Type: article
Authors: Gaia Collaboration; Babusiaux, C.; van Leeuwen, F.; Barstow, M. A.; Jordi, C.; Vallenari, A.; Bossini, D.; Bressan, A.; Cantat-Gaudin, T.; van Leeuwen, M.; Brown, A. G. A.; Prusti, T.; de Bruijne, J. H. J.; Bailer-Jones, C. A. L.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Walton, N. A.; Arenou, F.; Bastian, U.; Cropper, M.; Drimmel, R.; Katz, D.; Lattanzi, M. G.; Bakker, J.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Holl, B.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Panuzzo, P.; Portell, J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Teyssier, D.; Altmann, M.; Andrae, R.; Audard, M.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Burgess, P.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Clotet, M.; Creevey, O.; Davidson, M.; De Ridder, J.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Fernández-Hernández, J.; Fouesneau, M.; Frémat, Y.; Galluccio, L.; García-Torres, M.; González-Núñez, J.; González-Vidal, J. J.; Gosset, E.; Guy, L. P.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hernández, J.; Hestroffer, D.; Hodgkin, S. T.; Hutton, A.; Jasniewicz, G.; Jean-Antoine-Piccolo, A.; Jordan, S.; Korn, A. J.; Krone-Martins, A.; Lanzafame, A. C.; Lebzelter, T.; Löffler, W.; Manteiga, M.; Marrese, P. M.; Martín-Fleitas, J. M.; Moitinho, A.; Mora, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Richards, P. J.; Rimoldini, L.; Robin, A. C.; Sarro, L. M.; Siopis, C.; Smith, M.; Sozzetti, A.; Süveges, M.; Torra, J.; van Reeven, W.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aerts, C.; Altavilla, G.; Álvarez, M. A.; Alvarez, R.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Arcay, B.; Astraatmadja, T. L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Balm, P.; Barache, C.; Barata, C.; Barbato, D.; Barblan, F.; Barklem, P. S.; Barrado, D.; Barros, M.; Bartholomé Muñoz, L.; Bassilana, J. -L; Becciani, U.; Bellazzini, M.; Berihuete, A.; Bertone, S.; Bianchi, L.; Bienaymé, O.; Blanco-Cuaresma, Sergi; Boch, T.; Boeche, C.; Bombrun, A.; Borrachero, R.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Bramante, L.; Breddels, M. A.; Brouillet, N.; Brüsemeister, T.; Brugaletta, E.; Bucciarelli, B.; Burlacu, A.; Busonero, D.; Butkevich, A. G.; Buzzi, R.; Caffau, E.; Cancelliere, R.; Cannizzaro, G.; Carballo, R.; Carlucci, T.; Carrasco, J. M.; Casamiquela, L.; Castellani, M.; Castro-Ginard, A.; Charlot, P.; Chemin, L.; Chiavassa, A.; Cocozza, G.; Costigan, G.; Cowell, S.; Crifo, F.; Crosta, M.; Crowley, C.; Cuypers, J.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; de Laverny, P.; De Luise, F.; De March, R.; De Martino, D.; de Souza, R.; de Torres, A.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Diakite, S.; Diener, C.; Distefano, E.; Dolding, C.; Drazinos, P.; Durán, J.; Edvardsson, B.; Enke, H.; Eriksson, K.; Esquej, P.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernique, P.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fraile, E.; Fraser, M.; Frézouls, B.; Gai, M.; Galleti, S.; Garabato, D.; García-Sedano, F.; Garofalo, A.; Garralda, N.; Gavel, A.; Gavras, P.; Gerssen, J.; Geyer, R.; Giacobbe, P.; Gilmore, G.; Girona, S.; Giuffrida, G.; Glass, F.; Gomes, M.; Granvik, M.; Gueguen, A.; Guerrier, A.; Guiraud, J.; Gutié, R.; Haigron, R.; Hatzidimitriou, D.; Hauser, M.; Haywood, M.; Heiter, U.; Helmi, A.; Heu, J.; Hilger, T.; Hobbs, D.; Hofmann, W.; Holland, G.; Huckle, H. E.; Hypki, A.; Icardi, V.; Janßen, K.; Jevardat de Fombelle, G.; Jonker, P. G.; Juhász, Á. L.; Julbe, F.; Karampelas, A.; Kewley, A.; Klar, J.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, M.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Kostrzewa-Rutkowska, Z.; Koubsky, P.; Lambert, S.; Lanza, A. F.; Lasne, Y.; Lavigne, J. -B; Le Fustec, Y.; Le Poncin-Lafitte, C.; Lebreton, Y.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; López, M.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marinoni, S.; Marschalkó, G.; Marshall, D. J.; Martino, M.; Marton, G.; Mary, N.; Massari, D.; Matijevic, G.; Mazeh, T.; McMillan, P. J.; Messina, S.; Michalik, D.; Millar, N. R.; Molina, D.; Molinaro, R.; Molnár, L.; Montegriffo, P.; Mor, R.; Morbidelli, R.; Morel, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Nelemans, G.; Nicastro, L.; Noval, L.; O'Mullane, W.; Ordénovic, C.; Ordóñez-Blanco, D.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Panahi, A.; Pawlak, M.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poggio, E.; Poujoulet, E.; Prsa, A.; Pulone, L.; Racero, E.; Ragaini, S.; Rambaux, N.; Ramos-Lerate, M.; Regibo, S.; Reylé, C.; Riclet, F.; Ripepi, V.; Riva, A.; Rivard, A.; Rixon, G.; Roegiers, T.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sanna, N.; Santana-Ros, T.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Ségransan, D.; Shih, I. -C; Siltala, L.; Silva, A. F.; Smart, R. L.; Smith, K. W.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Teyssandier, P.; Thuillot, W.; Titarenko, A.; Torra Clotet, F.; Turon, C.; Ulla, A.; Utrilla, E.; Uzzi, S.; Vaillant, M.; Valentini, G.; Valette, V.; van Elteren, A.; Van Hemelryck, E.; Vaschetto, M.; Vecchiato, A.; Veljanoski, J.; Viala, Y.; Vicente, D.; Vogt, S.; von Essen, C.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Wertz, O.; Wevers, T.; Wyrzykowski, L.; Yoldas, A.; Zerjal, M.; Ziaeepour, H.; Zorec, J.; Zschocke, S.; Zucker, S.; Zurbach, C.; Zwitter, T.
Abstract: Context. Gaia Data Release 2 provides high-precision astrometry and three-band photometry for about 1.3 billion sources over the full sky. The precision, accuracy, and homogeneity of both astrometry and photometry are unprecedented.
Aims: We highlight the power of the Gaia DR2 in studying many fine structures of the Hertzsprung-Russell diagram (HRD). Gaia allows us to present many different HRDs, depending in particular on stellar population selections. We do not aim here for completeness in terms of types of stars or stellar evolutionary aspects. Instead, we have chosen several illustrative examples.
Methods: We describe some of the selections that can be made in Gaia DR2 to highlight the main structures of the Gaia HRDs. We select both field and cluster (open and globular) stars, compare the observations with previous classifications and with stellar evolutionary tracks, and we present variations of the Gaia HRD with age, metallicity, and kinematics. Late stages of stellar evolution such as hot subdwarfs, post-AGB stars, planetary nebulae, and white dwarfs are also analysed, as well as low-mass brown dwarf objects.
Results: The Gaia HRDs are unprecedented in both precision and coverage of the various Milky Way stellar populations and stellar evolutionary phases. Many fine structures of the HRDs are presented. The clear split of the white dwarf sequence into hydrogen and helium white dwarfs is presented for the first time in an HRD. The relation between kinematics and the HRD is nicely illustrated. Two different populations in a classical kinematic selection of the halo are unambiguously identified in the HRD. Membership and mean parameters for a selected list of open clusters are provided. They allow drawing very detailed cluster sequences, highlighting fine structures, and providing extremely precise empirical isochrones that will lead to more insight in stellar physics.
Conclusions: Gaia DR2 demonstrates the potential of combining precise astrometry and photometry for large samples for studies in stellar evolution and stellar population and opens an entire new area for HRD-based studies. The full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A10

ID: 149011
Type: article
Authors: Gaia Collaboration; Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; Babusiaux, C.; Bailer-Jones, C. A. L.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; van Leeuwen, F.; Walton, N. A.; Arenou, F.; Bastian, U.; Cropper, M.; Drimmel, R.; Katz, D.; Lattanzi, M. G.; Bakker, J.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Holl, B.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Panuzzo, P.; Portell, J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Teyssier, D.; Altmann, M.; Andrae, R.; Audard, M.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Burgess, P.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Clotet, M.; Creevey, O.; Davidson, M.; De Ridder, J.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Fernández-Hernández, J.; Fouesneau, M.; Frémat, Y.; Galluccio, L.; García-Torres, M.; González-Núñez, J.; González-Vidal, J. J.; Gosset, E.; Guy, L. P.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hernández, J.; Hestroffer, D.; Hodgkin, S. T.; Hutton, A.; Jasniewicz, G.; Jean-Antoine-Piccolo, A.; Jordan, S.; Korn, A. J.; Krone-Martins, A.; Lanzafame, A. C.; Lebzelter, T.; Löffler, W.; Manteiga, M.; Marrese, P. M.; Martín-Fleitas, J. M.; Moitinho, A.; Mora, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Richards, P. J.; Rimoldini, L.; Robin, A. C.; Sarro, L. M.; Siopis, C.; Smith, M.; Sozzetti, A.; Süveges, M.; Torra, J.; van Reeven, W.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aerts, C.; Altavilla, G.; Álvarez, M. A.; Alvarez, R.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Arcay, B.; Astraatmadja, T. L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Balm, P.; Barache, C.; Barata, C.; Barbato, D.; Barblan, F.; Barklem, P. S.; Barrado, D.; Barros, M.; Barstow, M. A.; Bartholomé Muñoz, S.; Bassilana, J. -L; Becciani, U.; Bellazzini, M.; Berihuete, A.; Bertone, S.; Bianchi, L.; Bienaymé, O.; Blanco-Cuaresma, Sergi; Boch, T.; Boeche, C.; Bombrun, A.; Borrachero, R.; Bossini, D.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Bramante, L.; Breddels, M. A.; Bressan, A.; Brouillet, N.; Brüsemeister, T.; Brugaletta, E.; Bucciarelli, B.; Burlacu, A.; Busonero, D.; Butkevich, A. G.; Buzzi, R.; Caffau, E.; Cancelliere, R.; Cannizzaro, G.; Cantat-Gaudin, T.; Carballo, R.; Carlucci, T.; Carrasco, J. M.; Casamiquela, L.; Castellani, M.; Castro-Ginard, A.; Charlot, P.; Chemin, L.; Chiavassa, A.; Cocozza, G.; Costigan, G.; Cowell, S.; Crifo, F.; Crosta, M.; Crowley, C.; Cuypers, J.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; de Laverny, P.; De Luise, F.; De March, R.; De Martino, D.; de Souza, R.; de Torres, A.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Di Matteo, P.; Diakite, S.; Diener, C.; Distefano, E.; Dolding, C.; Drazinos, P.; Durán, J.; Edvardsson, B.; Enke, H.; Eriksson, K.; Esquej, P.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernique, P.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fraile, E.; Fraser, M.; Frézouls, B.; Gai, M.; Galleti, S.; Garabato, D.; García-Sedano, F.; Garofalo, A.; Garralda, N.; Gavel, A.; Gavras, P.; Gerssen, J.; Geyer, R.; Giacobbe, P.; Gilmore, G.; Girona, S.; Giuffrida, G.; Glass, F.; Gomes, M.; Granvik, M.; Gueguen, A.; Guerrier, A.; Guiraud, J.; Gutiérrez-Sánchez, R.; Haigron, R.; Hatzidimitriou, D.; Hauser, M.; Haywood, M.; Heiter, U.; Helmi, A.; Heu, J.; Hilger, T.; Hobbs, D.; Hofmann, W.; Holland, G.; Huckle, H. E.; Hypki, A.; Icardi, V.; Janßen, K.; Jevardat de Fombelle, G.; Jonker, P. G.; Juhász, Á. L.; Julbe, F.; Karampelas, A.; Kewley, A.; Klar, J.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, M.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Kostrzewa-Rutkowska, Z.; Koubsky, P.; Lambert, S.; Lanza, A. F.; Lasne, Y.; Lavigne, J. -B; Le Fustec, Y.; Le Poncin-Lafitte, C.; Lebreton, Y.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; López, M.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marinoni, S.; Marschalkó, G.; Marshall, D. J.; Martino, M.; Marton, G.; Mary, N.; Massari, D.; Matijevic, G.; Mazeh, T.; McMillan, P. J.; Messina, S.; Michalik, D.; Millar, N. R.; Molina, D.; Molinaro, R.; Molnár, L.; Montegriffo, P.; Mor, R.; Morbidelli, R.; Morel, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Nelemans, G.; Nicastro, L.; Noval, L.; O'Mullane, W.; Ordénovic, C.; Ordóñez-Blanco, D.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Panahi, A.; Pawlak, M.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poggio, E.; Poujoulet, E.; Prsa, A.; Pulone, L.; Racero, E.; Ragaini, S.; Rambaux, N.; Ramos-Lerate, M.; Regibo, S.; Reylé, C.; Riclet, F.; Ripepi, V.; Riva, A.; Rivard, A.; Rixon, G.; Roegiers, T.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sanna, N.; Santana-Ros, T.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Ségransan, D.; Shih, I. -C; Siltala, L.; Silva, A. F.; Smart, R. L.; Smith, K. W.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Teyssandier, P.; Thuillot, W.; Titarenko, A.; Torra Clotet, F.; Turon, C.; Ulla, A.; Utrilla, E.; Uzzi, S.; Vaillant, M.; Valentini, G.; Valette, V.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Vaschetto, M.; Vecchiato, A.; Veljanoski, J.; Viala, Y.; Vicente, D.; Vogt, S.; von Essen, C.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Wertz, O.; Wevers, T.; Wyrzykowski, L.; Yoldas, A.; Zerjal, M.; Ziaeepour, H.; Zorec, J.; Zschocke, S.; Zucker, S.; Zurbach, C.; Zwitter, T.
Abstract: Context. We present the second Gaia data release, Gaia DR2, consisting of astrometry, photometry, radial velocities, and information on astrophysical parameters and variability, for sources brighter than magnitude 21. In addition epoch astrometry and photometry are provided for a modest sample of minor planets in the solar system.
Aims: A summary of the contents of Gaia DR2 is presented, accompanied by a discussion on the differences with respect to Gaia DR1 and an overview of the main limitations which are still present in the survey. Recommendations are made on the responsible use of Gaia DR2 results.
Methods: The raw data collected with the Gaia instruments during the first 22 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into this second data release, which represents a major advance with respect to Gaia DR1 in terms of completeness, performance, and richness of the data products.
Results: Gaia DR2 contains celestial positions and the apparent brightness in G for approximately 1.7 billion sources. For 1.3 billion of those sources, parallaxes and proper motions are in addition available. The sample of sources for which variability information is provided is expanded to 0.5 million stars. This data release contains four new elements: broad-band colour information in the form of the apparent brightness in the G_BP (330-680 nm) and G_RP (630-1050 nm) bands is available for 1.4 billion sources; median radial velocities for some 7 million sources are presented; for between 77 and 161 million sources estimates are provided of the stellar effective temperature, extinction, reddening, and radius and luminosity; and for a pre-selected list of 14 000 minor planets in the solar system epoch astrometry and photometry are presented. Finally, Gaia DR2 also represents a new materialisation of the celestial reference frame in the optical, the Gaia-CRF2, which is the first optical reference frame based solely on extragalactic sources. There are notable changes in the photometric system and the catalogue source list with respect to Gaia DR1, and we stress the need to consider the two data releases as independent.
Conclusions: Gaia DR2 represents a major achievement for the Gaia mission, delivering on the long standing promise to provide parallaxes and proper motions for over 1 billion stars, and representing a first step in the availability of complementary radial velocity and source astrophysical information for a sample of stars in the Gaia survey which covers a very substantial fraction of the volume of our galaxy.

ID: 149008
Type: article
Authors: Gaia Collaboration; Helmi, A.; van Leeuwen, F.; McMillan, P. J.; Massari, D.; Antoja, T.; Robin, A. C.; Lindegren, L.; Bastian, U.; Arenou, F.; Babusiaux, C.; Biermann, M.; Breddels, M. A.; Hobbs, D.; Jordi, C.; Pancino, E.; Reylé, C.; Veljanoski, J.; Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; Bailer-Jones, C. A. L.; Evans, D. W.; Eyer, L.; Jansen, F.; Klioner, S. A.; Lammers, U.; Luri, X.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Walton, N. A.; Cropper, M.; Drimmel, R.; Katz, D.; Lattanzi, M. G.; Bakker, J.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Holl, B.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Panuzzo, P.; Portell, J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Teyssier, D.; Altmann, M.; Andrae, R.; Audard, M.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Burgess, P.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Clotet, M.; Creevey, O.; Davidson, M.; De Ridder, J.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Fernández-Hernández, J.; Fouesneau, M.; Frémat, Y.; Galluccio, L.; García-Torres, M.; González-Núñez, J.; González-Vidal, J. J.; Gosset, E.; Guy, L. P.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hernández, J.; Hestroffer, D.; Hodgkin, S. T.; Hutton, A.; Jasniewicz, G.; Jean-Antoine-Piccolo, A.; Jordan, S.; Korn, A. J.; Krone-Martins, A.; Lanzafame, A. C.; Lebzelter, T.; Löffler, W.; Manteiga, M.; Marrese, P. M.; Martín-Fleitas, J. M.; Moitinho, A.; Mora, A.; Muinonen, K.; Osinde, J.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Richards, P. J.; Rimoldini, L.; Sarro, L. M.; Siopis, C.; Smith, M.; Sozzetti, A.; Süveges, M.; Torra, J.; van Reeven, W.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aerts, C.; Altavilla, G.; Álvarez, M. A.; Alvarez, R.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Arcay, B.; Astraatmadja, T. L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Balm, P.; Barache, C.; Barata, C.; Barbato, D.; Barblan, F.; Barklem, P. S.; Barrado, D.; Barros, M.; Barstow, M. A.; Bartholomé Muñoz, S.; Bassilana, J. -L; Becciani, U.; Bellazzini, M.; Berihuete, A.; Bertone, S.; Bianchi, L.; Bienaymé, O.; Blanco-Cuaresma, Sergi; Boch, T.; Boeche, C.; Bombrun, A.; Borrachero, R.; Bossini, D.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Bramante, L.; Bressan, A.; Brouillet, N.; Brüsemeister, T.; Brugaletta, E.; Bucciarelli, B.; Burlacu, A.; Busonero, D.; Butkevich, A. G.; Buzzi, R.; Caffau, E.; Cancelliere, R.; Cannizzaro, G.; Cantat-Gaudin, T.; Carballo, R.; Carlucci, T.; Carrasco, J. M.; Casamiquela, L.; Castellani, M.; Castro-Ginard, A.; Charlot, P.; Chemin, L.; Chiavassa, A.; Cocozza, G.; Costigan, G.; Cowell, S.; Crifo, F.; Crosta, M.; Crowley, C.; Cuypers, J.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; de Laverny, P.; De Luise, F.; De March, R.; De Martino, D.; de Souza, R.; de Torres, A.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Di Matteo, P.; Diakite, S.; Diener, C.; Distefano, E.; Dolding, C.; Drazinos, P.; Durán, J.; Edvardsson, B.; Enke, H.; Eriksson, K.; Esquej, P.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernique, P.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fraile, E.; Fraser, M.; Frézouls, B.; Gai, M.; Galleti, S.; Garabato, D.; García-Sedano, F.; Garofalo, A.; Garralda, N.; Gavel, A.; Gavras, P.; Gerssen, J.; Geyer, R.; Giacobbe, P.; Gilmore, G.; Girona, S.; Giuffrida, G.; Glass, F.; Gomes, M.; Granvik, M.; Gueguen, A.; Guerrier, A.; Guiraud, J.; Gutiérrez-Sánchez, R.; Hofmann, W.; Holland, G.; Huckle, H. E.; Hypki, A.; Icardi, V.; Janßen, K.; Jevardat de Fombelle, G.; Jonker, P. G.; Juhász, Á. L.; Julbe, F.; Karampelas, A.; Kewley, A.; Klar, J.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, M.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Kostrzewa-Rutkowska, Z.; Koubsky, P.; Lambert, S.; Lanza, A. F.; Lasne, Y.; Lavigne, J. -B; Le Fustec, Y.; Le Poncin-Lafitte, C.; Lebreton, Y.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; López, M.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marinoni, S.; Marschalkó, G.; Marshall, D. J.; Martino, M.; Marton, G.; Mary, N.; Matijevic, G.; Mazeh, T.; Messina, S.; Michalik, D.; Millar, N. R.; Molina, D.; Molinaro, R.; Molnár, L.; Montegriffo, P.; Mor, R.; Morbidelli, R.; Morel, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Nelemans, G.; Nicastro, L.; Noval, L.; O'Mullane, W.; Ordénovic, C.; Ordóñez-Blanco, D.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Panahi, A.; Pawlak, M.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poggio, E.; Poujoulet, E.; Prsa, A.; Pulone, L.; Racero, E.; Ragaini, S.; Rambaux, N.; Ramos-Lerate, M.; Regibo, S.; Riclet, F.; Ripepi, V.; Riva, A.; Rivard, A.; Rixon, G.; Roegiers, T.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sanna, N.; Santana-Ros, T.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Ségransan, D.; Shih, I. -C; Siltala, L.; Silva, A. F.; Smart, R. L.; Smith, K. W.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Teyssandier, P.; Thuillot, W.; Titarenko, A.; Torra Clotet, F.; Turon, C.; Ulla, A.; Utrilla, E.; Uzzi, S.; Vaillant, M.; Valentini, G.; Valette, V.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Vaschetto, M.; Vecchiato, A.; Viala, Y.; Vicente, D.; Vogt, S.; von Essen, C.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Wertz, O.; Wevems, T.; Wyrzykowski, L.; Yoldas, A.; Zerjal, M.; Ziaeepour, H.; Zorec, J.; Zschocke, S.; Zucker, S.; Zurbach, C.; Zwitter, T.
Abstract: Context.
Aims: The goal of this paper is to demonstrate the outstanding quality of the second data release of the Gaia mission and its power for constraining many different aspects of the dynamics of the satellites of the Milky Way. We focus here on determining the proper motions of 75 Galactic globular clusters, nine dwarf spheroidal galaxies, one ultra-faint system, and the Large and Small Magellanic Clouds.
Methods: Using data extracted from the Gaia archive, we derived the proper motions and parallaxes for these systems, as well as their uncertainties. We demonstrate that the errors, statistical and systematic, are relatively well understood. We integrated the orbits of these objects in three different Galactic potentials, and characterised their properties. We present the derived proper motions, space velocities, and characteristic orbital parameters in various tables to facilitate their use by the astronomical community.
Results: Our limited and straightforward analyses have allowed us for example to (i) determine absolute and very precise proper motions for globular clusters; (ii) detect clear rotation signatures in the proper motions of at least five globular clusters; (iii) show that the satellites of the Milky Way are all on high-inclination orbits, but that they do not share a single plane of motion; (iv) derive a lower limit for the mass of the Milky Way of 9.1_-2.6^+6.2 × 10¹¹ M_&sun; based on the assumption that the Leo I dwarf spheroidal is bound; (v) derive a rotation curve for the Large Magellanic Cloud based solely on proper motions that is competitive with line-of-sight velocity curves, now using many orders of magnitude more sources; and (vi) unveil the dynamical effect of the bar on the motions of stars in the Large Magellanic Cloud.
Conclusions: All these results highlight the incredible power of the Gaia astrometric mission, and in particular of its second data release. Full Table D.3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A12

ID: 149009
Type: article
Authors: Gaia Collaboration; Katz, D.; Antoja, T.; Romero-Gómez, M.; Drimmel, R.; Reylé, C.; Seabroke, G. M.; Soubiran, C.; Babusiaux, C.; Di Matteo, P.; Figueras, F.; Poggio, E.; Robin, A. C.; Evans, D. W.; Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; Bailer-Jones, C. A. L.; Biermann, M.; Eyer, L.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; Mignard, F.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; van Leeuwen, F.; Walton, N. A.; Arenou, F.; Bastian, U.; Cropper, M.; Lattanzi, M. G.; Bakker, J.; Cacciari, C.; Casta n, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Holl, B.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Panuzzo, P.; Portell, J.; Riello, M.; Tanga, P.; Thévenin, F.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Teyssier, D.; Altmann, M.; Andrae, R.; Audard, M.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Burgess, P.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Clotet, M.; Creevey, O.; Davidson, M.; De Ridder, J.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Fernández-Hernández, J.; Fouesneau, M.; Frémat, Y.; Galluccio, L.; García-Torres, M.; González-Núñez, J.; González-Vidal, J. J.; Gosset, E.; Guy, L. P.; Halbwachs, J. -L; Hambly, N. C.; Harrison, D. L.; Hernández, J.; Hestroffer, D.; Hodgkin, S. T.; Hutton, A.; Jasniewicz, G.; Jean-Antoine-Piccolo, A.; Jordan, S.; Korn, A. J.; Krone-Martins, A.; Lanzafame, A. C.; Lebzelter, T.; Löffler, W.; Manteiga, M.; Marrese, P. M.; Martín-Fleitas, J. M.; Moitinho, A.; Mora, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J. -M; Recio-Blanco, A.; Richards, P. J.; Rimoldini, L.; Sarro, L. M.; Siopis, C.; Smith, M.; Sozzetti, A.; Süveges, M.; Torra, J.; van Reeven, W.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aerts, C.; Altavilla, G.; Álvarez, M. A.; Alvarez, R.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Arcay, B.; Astraatmadja, T. L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Balm, P.; Barache, C.; Barata, C.; Barbato, D.; Barblan, F.; Barklem, P. S.; Barrado, D.; Barros, M.; Barstow, M. A.; Bartholomé Muñoz, L.; Bassilana, J. -L; Becciani, U.; Bellazzini, M.; Berihuete, A.; Bertone, S.; Bianchi, L.; Bienaymé, O.; Blanco-Cuaresma, Sergi; Boch, T.; Boeche, C.; Bombrun, A.; Borrachero, R.; Bossini, D.; Bouquillon, S.; Bourda, G.; Bragaglia, A.; Bramante, L.; Breddels, M. A.; Bressan, A.; Brouillet, N.; Brüsemeister, T.; Brugaletta, E.; Bucciarelli, B.; Burlacu, A.; Busonero, D.; Butkevich, A. G.; Buzzi, R.; Caffau, E.; Cancelliere, R.; Cannizzaro, G.; Cantat-Gaudin, T.; Carballo, R.; Carlucci, T.; Carrasco, J. M.; Casamiquela, L.; Castellani, M.; Castro-Ginard, A.; Charlot, P.; Chemin, L.; Chiavassa, A.; Cocozza, G.; Costigan, G.; Cowell, S.; Crifo, F.; Crosta, M.; Crowley, C.; Cuypers, J.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; de Laverny, P.; De Luise, F.; De March, R.; de Souza, R.; de Torres, A.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; Diakite, S.; Diener, C.; Distefano, E.; Dolding, C.; Drazinos, P.; Durán, J.; Edvardsson, B.; Enke, H.; Eriksson, K.; Esquej, P.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falc a, A. J.; Farràs Casas, M.; Federici, L.; Fedorets, G.; Fernique, P.; Filippi, F.; Findeisen, K.; Fonti, A.; Fraile, E.; Fraser, M.; Frézouls, B.; Gai, M.; Galleti, S.; Garabato, D.; García-Sedano, F.; Garofalo, A.; Garralda, N.; Gavel, A.; Gavras, P.; Gerssen, J.; Geyer, R.; Giacobbe, P.; Gilmore, G.; Girona, S.; Giuffrida, G.; Glass, F.; Gomes, M.; Granvik, M.; Gueguen, A.; Guerrier, A.; Guiraud, J.; Gutié, R.; Haigron, R.; Hatzidimitriou, D.; Hauser, M.; Haywood, M.; Heiter, U.; Helmi, A.; Heu, J.; Hilger, T.; Hobbs, D.; Hofmann, W.; Holland, G.; Huckle, H. E.; Hypki, A.; Icardi, V.; Janßen, K.; Jevardat de Fombelle, G.; Jonker, P. G.; Juhász, Á. L.; Julbe, F.; Karampelas, A.; Kewley, A.; Klar, J.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, M.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Kostrzewa-Rutkowska, Z.; Koubsky, P.; Lambert, S.; Lanza, A. F.; Lasne, Y.; Lavigne, J. -B; Le Fustec, Y.; Le Poncin-Lafitte, C.; Lebreton, Y.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; López, M.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marinoni, S.; Marschalkó, G.; Marshall, D. J.; Martino, M.; Marton, G.; Mary, N.; Massari, D.; Matijevic, G.; Mazeh, T.; McMillan, P. J.; Messina, S.; Michalik, D.; Millar, N. R.; Molina, D.; Molinaro, R.; Molnár, L.; Montegriffo, P.; Mor, R.; Morbidelli, R.; Morel, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Nelemans, G.; Nicastro, L.; Noval, L.; O'Mullane, W.; Ordénovic, C.; Ordóñez-Blanco, D.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Panahi, A.; Pawlak, M.; Piersimoni, A. M.; Pineau, F. -X; Plachy, E.; Plum, G.; Poujoulet, E.; Prsa, A.; Pulone, L.; Racero, E.; Ragaini, S.; Rambaux, N.; Ramos-Lerate, M.; Regibo, S.; Riclet, F.; Ripepi, V.; Riva, A.; Rivard, A.; Rixon, G.; Roegiers, T.; Roelens, M.; Rowell, N.; Royer, F.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sanna, N.; Santana-Ros, T.; Sarasso, M.; Savietto, H.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Ségransan, D.; Shih, I. -C; Siltala, L.; Silva, A. F.; Smart, R. L.; Smith, K. W.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Teyssandier, P.; Thuillot, W.; Titarenko, A.; Torra Clotet, F.; Turon, C.; Ulla, A.; Utrilla, E.; Uzzi, S.; Vaillant, M.; Valentini, G.; Valette, V.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Vaschetto, M.; Vecchiato, A.; Veljanoski, J.; Viala, Y.; Vicente, D.; Vogt, S.; von Essen, C.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Wertz, O.; Wevers, T.; Wyrzykowski, L.; Yoldas, A.; Zerjal, M.; Ziaeepour, H.; Zorec, J.; Zschocke, S.; Zucker, S.; Zurbach, C.; Zwitter, T.
Abstract: Context. The second Gaia data release (Gaia DR2) contains high-precision positions, parallaxes, and proper motions for 1.3 billion sources as well as line-of-sight velocities for 7.2 million stars brighter than G_RVS = 12 mag. Both samples provide a full sky coverage.
Aims: To illustrate the potential of Gaia DR2, we provide a first look at the kinematics of the Milky Way disc, within a radius of several kiloparsecs around the Sun.
Methods: We benefit for the first time from a sample of 6.4 million F-G-K stars with full 6D phase-space coordinates, precise parallaxes (sigma_varpi/varpi /varpi ^-1 and 20% of the stars with uncertainties smaller than 1 km s^-1 on all three components). From this sample, we extracted a sub-sample of 3.2 million giant stars to map the velocity field of the Galactic disc from 5 kpc to 13 kpc from the Galactic centre and up to 2 kpc above and below the plane. We also study the distribution of 0.3 million solar neighbourhood stars (r on all three components). From this sample, we extracted a sub-sample of 3.2 million giant stars to map the velocity field of the Galactic disc from 5 kpc to 13 kpc from the Galactic centre and up to 2 kpc above and below the plane. We also study the distribution of 0.3 million solar neighbourhood stars (r ^-1, in velocity space and use the full sample to examine how the over-densities evolve in more distant regions.
Results: Gaia DR2 allows us to draw 3D maps of the Galactocentric median velocities and velocity dispersions with unprecedented accuracy, precision, and spatial resolution. The maps show the complexity and richness of the velocity field of the galactic disc. We observe streaming motions in all the components of the velocities as well as patterns in the velocity dispersions. For example, we confirm the previously reported negative and positive galactocentric radial velocity gradients in the inner and outer disc, respectively. Here, we see them as part of a non-axisymmetric kinematic oscillation, and we map its azimuthal and vertical behaviour. We also witness a new global arrangement of stars in the velocity plane of the solar neighbourhood and in distant regions in which stars are organised in thin substructures with the shape of circular arches that are oriented approximately along the horizontal direction in the U - V plane. Moreover, in distant regions, we see variations in the velocity substructures more clearly than ever before, in particular, variations in the velocity of the Hercules stream.
Conclusions: Gaia DR2 provides the largest existing full 6D phase-space coordinates catalogue. It also vastly increases the number of available distances and transverse velocities with respect to Gaia DR1. Gaia DR2 offers a great wealth of information on the Milky Way and reveals clear non-axisymmetric kinematic signatures within the Galactic disc, for instance. It is now up to the astronomical community to explore its full potential.