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Showing 1-20 of about 67 results.
KMT-2017-BLG-2820 and the Nature of the Free-floating Planet PopulationRyu, Yoon-HyunMróz, PrzemekGould, AndrewHwang, Kyu-HaKim, Hyoun-WooYee, Jennifer C.Albrow, Michael D.Chung, Sun-JuJung, Youn KilShin, In-GuShvartzvald, YossiZang, WeichengCha, Sang-MokKim, Dong-JinKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonHan, CheonghoPogge, Richard W.KMTNet CollaborationUdalski, AndrzejPoleski, RadekSkowron, JanSzymański, Michał K.Soszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykOGLE CollaborationDOI: info:10.3847/1538-3881/abd55fv. 161126
Ryu, Yoon-Hyun, Mróz, Przemek, Gould, Andrew, Hwang, Kyu-Ha, Kim, Hyoun-Woo, Yee, Jennifer C., Albrow, Michael D., Chung, Sun-Ju, Jung, Youn Kil, Shin, In-Gu, Shvartzvald, Yossi, Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Han, Cheongho, Pogge, Richard W., KMTNet Collaboration, Udalski, Andrzej, Poleski, Radek, Skowron, Jan et al. 2021. "KMT-2017-BLG-2820 and the Nature of the Free-floating Planet Population." The Astronomical Journal 161:126. https://doi.org/10.3847/1538-3881/abd55f
ID: 159330
Type: article
Authors: Ryu, Yoon-Hyun; Mróz, Przemek; Gould, Andrew; Hwang, Kyu-Ha; Kim, Hyoun-Woo; Yee, Jennifer C.; Albrow, Michael D.; Chung, Sun-Ju; Jung, Youn Kil; Shin, In-Gu; Shvartzvald, Yossi; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Han, Cheongho; Pogge, Richard W.; KMTNet Collaboration; Udalski, Andrzej; Poleski, Radek; Skowron, Jan; Szymański, Michał K.; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; OGLE Collaboration
Abstract: We report a new free-floating planet (FFP) candidate, KMT-2017-BLG-2820, with Einstein radius θE ≃ 6 μas, lens-source relative proper motion μrel ≃ 8 mas yr-1, and Einstein timescale tE = 6.5 hr. It is the third FFP candidate found in an ongoing study of giant-source finite-source point-lens (FSPL) events in the KMTNet database and the sixth FSPL FFP candidate overall. We find no significant evidence for a host. Based on their timescale distributions and detection rates, we argue that five of these six FSPL FFP candidates are drawn from the same population as the six point-source point-lens (PSPL) FFP candidates found by Mróz et al. in the OGLE-IV database. The θE distribution of the FSPL FFPs implies that they are either sub-Jovian planets in the bulge or super-Earths in the disk. However, the apparent "Einstein desert" (10 ≲ θE/μas ≲ 30) would argue for the latter. Whether each of the 12 (six FSPL and six PSPL) FFP candidates is truly an FFP or simply a very wide-separation planet can be determined at first adaptive optics (AO) light on 30 m telescopes, and earlier for some. If the latter, a second epoch of AO observations could measure the projected planet-host separation with a precision of ${ \mathcal O }(10\,\mathrm{au})$ . At the present time, the balance of evidence favors the unbound-planet hypothesis.
KMT-2018-BLG-0029Lb: A Very Low Mass-Ratio Spitzer Microlens PlanetGould, AndrewRyu, Yoon-HyunCalchi Novati, SebastianoZang, WeichengAlbrow, Michael D.Chung, Sun-JuHan, CheonghoHwang, Kyu-HaJung, Youn KilShin, In-GuShvartzvald, YossiYee, Jennifer C.Cha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.Beichman, CharlesBryden, GeoffCarey, SeanGaudi, B. ScottHenderson, Calen B.Zhu, WeiFouque, PascalPenny, Matthew T.Petric, AndreeaBurdullis, ToddMao, ShudeDOI: info:10.5303/JKAS.2020.53.1.9v. 539–26
Gould, Andrew, Ryu, Yoon-Hyun, Calchi Novati, Sebastiano, Zang, Weicheng, Albrow, Michael D., Chung, Sun-Ju, Han, Cheongho, Hwang, Kyu-Ha, Jung, Youn Kil, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Beichman, Charles, Bryden, Geoff, Carey, Sean, Gaudi, B. Scott et al. 2020. "KMT-2018-BLG-0029Lb: A Very Low Mass-Ratio Spitzer Microlens Planet." Journal of Korean Astronomical Society 53:9– 26. https://doi.org/10.5303/JKAS.2020.53.1.9
ID: 158017
Type: article
Authors: Gould, Andrew; Ryu, Yoon-Hyun; Calchi Novati, Sebastiano; Zang, Weicheng; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Beichman, Charles; Bryden, Geoff; Carey, Sean; Gaudi, B. Scott; Henderson, Calen B.; Zhu, Wei; Fouque, Pascal; Penny, Matthew T.; Petric, Andreea; Burdullis, Todd; Mao, Shude
Abstract: At q = (1.81+/-0.20)*10^-5, KMT-2018-BLG-0029Lb has the lowest planet-host mass ratio q of any microlensing planet to date by more than a factor of two. Hence, it is the first planet that probes below the apparent "pile-up" at q = 5-10*10^-5. The event was observed by Spitzer, yielding a microlens-parallax pi_E measurement. Combined with a measurement of the Einstein radius theta_E from finite-source effects during the caustic crossings, these measurements imply masses of the host M_host = 1.14 (+0.10, -0.12) M_sun and planet M_planet = 7.59 (+0.75, -0.69) M_Earth, system distance D_L = 3.38 (+0.22, -0.26) kpc and projected separation a_perp = 4.27 (+0.21, -0.23) au. The blended light, which is substantially brighter than the microlensed source, is plausibly due to the lens and could be observed at high resolution immediately.
One Planet or Two Planets? The Ultra-sensitive Extreme-magnification Microlensing Event KMT-2019-BLG-1953Han, CheonghoKim, DoeonJung, Youn KilGould, AndrewBond, Ian A.Albrow, Michael D.Chung, Sun-JuHwang, Kyu-HaLee, Chung-UkRyu, Yoon-HyunShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.Kim, Woong-TaeKMTNet CollaborationAbe, FumioBarry, RichardBennett, David P.Bhattacharya, AparnaDonachie, MartinFujii, HirosaneFukui, AkihikoItow, YoshitakaHirao, YukiKirikawa, RintaroKondo, IonaKoshimoto, NaokiLi, Man Cheung AlexMatsubara, YutakaMuraki, YasushiMiyazaki, ShotaNagakane, MasayukiRanc, ClémentRattenbury, Nicholas J.Satoh, YukiShoji, HikaruSuematsu, HarunoSumi, TakahiroSuzuki, DaisukeTanaka, YuzuruTristram, Paul J.Yamawaki, TsubasaYonehara, AtsunoriMOA CollaborationDOI: info:10.3847/1538-3881/ab91acv. 16017
Han, Cheongho, Kim, Doeon, Jung, Youn Kil, Gould, Andrew, Bond, Ian A., Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Lee, Chung-Uk, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Kim, Woong-Tae, KMTNet Collaboration, Abe, Fumio et al. 2020. "One Planet or Two Planets? The Ultra-sensitive Extreme-magnification Microlensing Event KMT-2019-BLG-1953." The Astronomical Journal 160:17. https://doi.org/10.3847/1538-3881/ab91ac
ID: 158878
Type: article
Authors: Han, Cheongho; Kim, Doeon; Jung, Youn Kil; Gould, Andrew; Bond, Ian A.; Albrow, Michael D.; Chung, Sun-Ju; Hwang, Kyu-Ha; Lee, Chung-Uk; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Kim, Woong-Tae; KMTNet Collaboration; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Donachie, Martin; Fujii, Hirosane; Fukui, Akihiko; Itow, Yoshitaka; Hirao, Yuki; Kirikawa, Rintaro; Kondo, Iona; Koshimoto, Naoki; Li, Man Cheung Alex; Matsubara, Yutaka; Muraki, Yasushi; Miyazaki, Shota; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Satoh, Yuki; Shoji, Hikaru; Suematsu, Haruno; Sumi, Takahiro; Suzuki, Daisuke; Tanaka, Yuzuru; Tristram, Paul J.; Yamawaki, Tsubasa; Yonehara, Atsunori; MOA Collaboration
Abstract: We present the analysis of a very high-magnification (A ˜ 900) microlensing event KMT-2019-BLG-1953. A single-lens single-source (1L1S) model appears to approximately delineate the observed light curve, but the residuals from the model exhibit small but obvious deviations in the peak region. A binary-lens (2L1S) model with a mass ratio of q ˜ 2 × 10-3 improves the fits by ??2 = 181.8, indicating that the lens possesses a planetary companion. From additional modeling by introducing an extra planetary lens component (3L1S model) and an extra source companion (2L2S model), it is found that the residuals from the 2L1S model further diminish, but claiming these interpretations is difficult due to the weak signals with ??2 = 16.0 and 13.5 for the 3L1S and 2L2L models, respectively. From a Bayesian analysis, we estimate that the host of the planets has a mass of ${M}_{\mathrm{host}}={0.31}_{-0.17}^{+0.37}\,{M}_{\odot }$ and that the planetary system is located at a distance of ${D}_{{\rm{L}}}={7.04}_{-1.33}^{+1.10}\,\mathrm{kpc}$ toward the Galactic center. The mass of the securely detected planet is ${M}_{{\rm{p}}}={0.64}_{-0.35}^{+0.76}\,{M}_{{\rm{J}}}$ . The signal of the potential second planet could have been confirmed if the peak of the light curve had been more densely observed by follow-up observations, and thus the event illustrates the need for intensive follow-up observations for very high-magnification events even in the current generation of high-cadence surveys.
KMT-2019-BLG-1339L: An M Dwarf with a Giant Planet or a Companion near the Planet/Brown Dwarf BoundaryHan, CheonghoKim, DoeonUdalski, AndrzejGould, AndrewAlbrow, Michael D.Chung, Sun-JuHwang, Kyu-HaJung, Youn KilLee, Chung-UkRyu, Yoon-HyunShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.KMTNet CollaborationMróz, PrzemekSzymański, Michał K.Skowron, JanPoleski, RadosławSoszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykWrona, MarcinGromadzki, MariuszOGLE CollaborationDOI: info:10.3847/1538-3881/ab9a3ev. 16064
Han, Cheongho, Kim, Doeon, Udalski, Andrzej, Gould, Andrew, Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Jung, Youn Kil, Lee, Chung-Uk, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., KMTNet Collaboration, Mróz, Przemek, Szymański, Michał K. et al. 2020. "KMT-2019-BLG-1339L: An M Dwarf with a Giant Planet or a Companion near the Planet/Brown Dwarf Boundary." The Astronomical Journal 160:64. https://doi.org/10.3847/1538-3881/ab9a3e
ID: 158015
Type: article
Authors: Han, Cheongho; Kim, Doeon; Udalski, Andrzej; Gould, Andrew; Albrow, Michael D.; Chung, Sun-Ju; Hwang, Kyu-Ha; Jung, Youn Kil; Lee, Chung-Uk; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; KMTNet Collaboration; Mróz, Przemek; Szymański, Michał K.; Skowron, Jan; Poleski, Radosław; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; Wrona, Marcin; Gromadzki, Mariusz; OGLE Collaboration
Abstract: We analyze KMT-2019-BLG-1339, a microlensing event with an obvious but incompletely resolved brief anomaly feature around the peak of the light curve. Although the origin of the anomaly is identified to be a companion to the lens with a low mass ratio q, the interpretation is subject to two different degeneracy types. The first type is the ambiguity in ρ, representing the angular source radius scaled to the angular radius of the Einstein ring, θE, and the other is the s ↔ s-1 degeneracy. The former type, "finite-source degeneracy," causes ambiguities in both s and q, while the latter induces an ambiguity only in s. Here, s denotes the separation (in units of θE) in projection between the lens components. We estimate that the lens components have masses $({M}_{1},{M}_{2})\sim ({0.27}_{-0.15}^{+0.36}\,{M}_{\odot },{11}_{-7}^{+16}\,{M}_{{\rm{J}}})$ and $\sim ({0.48}_{-0.28}^{+0.40}\,{M}_{\odot },{1.3}_{-0.7}^{+1.1}\,{M}_{{\rm{J}}})$ according to the two solutions subject to the finite-source degeneracy, indicating that the lens comprises an M dwarf and a companion with a mass around the planet/brown dwarf boundary or a Jovian-mass planet. It is possible to lift the finite-source degeneracy by conducting future observations utilizing a high-resolution instrument because the relative lens-source proper motion predicted by the solutions is widely different.
OGLE-2018-BLG-1700L: Microlensing Planet in Binary Stellar SystemHan, CheonghoLee, Chung-UkUdalski, AndrzejGould, AndrewBond, Ian A.Albrow, Michael D.Chung, Sun-JuHwang, Kyu-HaJung, Youn KilRyu, Yoon-HyunShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.Jee, M. JamesKim, DoeonMróz, PrzemekSzymański, Michał K.Skowron, JanPoleski, RadekSoszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykWrona, MarcinAbe, FumioBarry, RichardBennett, David P.Bhattacharya, AparnaDonachie, MartinFujii, HirosaneFukui, AkihikoItow, YoshitakaHirao, YukiKamei, YuheiKondo, IonaKoshimoto, NaokiLi, Man Cheung AlexMatsubara, YutakaMuraki, YasushiMiyazaki, ShotaNagakane, MasayukiRanc, ClémentRattenbury, Nicholas J.Suematsu, HarunoSullivan, Denis J.Sumi, TakahiroSuzuki, DaisukeTristram, Paul J.Yamakawa, TakeharuYonehara, AtsunoriDOI: info:10.3847/1538-3881/ab5db9v. 15948
Han, Cheongho, Lee, Chung-Uk, Udalski, Andrzej, Gould, Andrew, Bond, Ian A., Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Jung, Youn Kil, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Jee, M. James, Kim, Doeon, Mróz, Przemek et al. 2020. "OGLE-2018-BLG-1700L: Microlensing Planet in Binary Stellar System." The Astronomical Journal 159:48. https://doi.org/10.3847/1538-3881/ab5db9
ID: 155838
Type: article
Authors: Han, Cheongho; Lee, Chung-Uk; Udalski, Andrzej; Gould, Andrew; Bond, Ian A.; Albrow, Michael D.; Chung, Sun-Ju; Hwang, Kyu-Ha; Jung, Youn Kil; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Jee, M. James; Kim, Doeon; Mróz, Przemek; Szymański, Michał K.; Skowron, Jan; Poleski, Radek; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; Wrona, Marcin; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Donachie, Martin; Fujii, Hirosane; Fukui, Akihiko; Itow, Yoshitaka; Hirao, Yuki; Kamei, Yuhei; Kondo, Iona; Koshimoto, Naoki; Li, Man Cheung Alex; Matsubara, Yutaka; Muraki, Yasushi; Miyazaki, Shota; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Suematsu, Haruno; Sullivan, Denis J.; Sumi, Takahiro; Suzuki, Daisuke; Tristram, Paul J.; Yamakawa, Takeharu; Yonehara, Atsunori
Abstract: We report a planet in a binary that was discovered from the analysis of the microlensing event OGLE-2018-BLG-1700. We identify the triple nature of the lens from the fact that the anomaly pattern can be decomposed into two parts produced by two binary-lens events, in which one binary pair has a mass ratio of ∼0.01 between the lens components and the other pair has a mass ratio of ∼0.3. We find two sets of degenerate solutions, in which one solution has a projected separation between the primary and its stellar companion less than the angular Einstein radius {θ }{{E}} (close solution), while the other solution has a separation greater than {θ}{{E}} (wide solution). From the Bayesian analysis with the constraints of the event timescale and angular Einstein radius, we find that the planet has a mass of {4.4}-2.0+3.0 {M}{{J}} and the stellar binary components have masses of {0.42}-0.19+0.29 {M}ȯ and {0.12}-0.05+0.08 {M}ȯ , respectively, and the distance to the lens is {D}{{L}}={7.6}-0.9+1.2 {kpc}. The planet is a circumstellar planet according to the wide solution, while it is a circumbinary planet according to the close solution.
Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein RadiiHan, CheonghoLee, Chung-UkUdalski, AndrzejGould, AndrewBond, Ian A.Bozza, ValerioAlbrow, Michael D.Chung, Sun-JuHwang, Kyu-HaJung, Youn KilRyu, Yoon-HyunShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.Jee, M. JamesKim, DoeonKMTNet CollaborationMróz, PrzemekSzymański, Michał K.Skowron, JanPoleski, RadekSoszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykWrona, MarcinOGLE CollaborationAbe, FumioBarry, RichardBennett, David P.Bhattacharya, AparnaDonachie, MartinFujii, HirosaneFukui, AkihikoItow, YoshitakaHirao, YukiKamei, YuheiKondo, IonaKoshimoto, NaokiLi, Man Cheung AlexMatsubara, YutakaMuraki, YasushiMiyazaki, ShotaNagakane, MasayukiRanc, ClémentRattenbury, Nicholas J.Satoh, YukiShoji, HikaruSuematsu, HarunoSullivan, Denis J.Sumi, TakahiroSuzuki, DaisukeTristram, Paul J.Yamakawa, TakeharuYamawaki, TsubasaYonehara, AtsunoriMOA CollaborationDOI: info:10.3847/1538-3881/ab6f66v. 159134
Han, Cheongho, Lee, Chung-Uk, Udalski, Andrzej, Gould, Andrew, Bond, Ian A., Bozza, Valerio, Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Jung, Youn Kil, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Jee, M. James, Kim, Doeon et al. 2020. "Candidate Brown-dwarf Microlensing Events with Very Short Timescales and Small Angular Einstein Radii." The Astronomical Journal 159:134. https://doi.org/10.3847/1538-3881/ab6f66
ID: 156327
Type: article
Authors: Han, Cheongho; Lee, Chung-Uk; Udalski, Andrzej; Gould, Andrew; Bond, Ian A.; Bozza, Valerio; Albrow, Michael D.; Chung, Sun-Ju; Hwang, Kyu-Ha; Jung, Youn Kil; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Jee, M. James; Kim, Doeon; KMTNet Collaboration; Mróz, Przemek; Szymański, Michał K.; Skowron, Jan; Poleski, Radek; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; Wrona, Marcin; OGLE Collaboration; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Donachie, Martin; Fujii, Hirosane; Fukui, Akihiko; Itow, Yoshitaka; Hirao, Yuki; Kamei, Yuhei; Kondo, Iona; Koshimoto, Naoki; Li, Man Cheung Alex; Matsubara, Yutaka; Muraki, Yasushi; Miyazaki, Shota; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Satoh, Yuki; Shoji, Hikaru; Suematsu, Haruno; Sullivan, Denis J.; Sumi, Takahiro; Suzuki, Daisuke; Tristram, Paul J.; Yamakawa, Takeharu; Yamawaki, Tsubasa; Yonehara, Atsunori; MOA Collaboration
Abstract: Short-timescale microlensing events are likely to be produced by substellar brown dwarfs (BDs), but it is difficult to securely identify BD lenses based on only event timescales ${t}_{{\rm{E}}} because short- timescale events can also be produced by stellar lenses with high relative lens-source proper motions. In this paper, we report three strong candidate BD-lens events found from the search for lensing events not only with short timescales ( ${t}_{{\rm{E}}}\lesssim 6\,\mathrm{days} ) but also with very small angular Einstein radii ( ${\theta }_{{\rm{E}}}\lesssim 0.05\,\mathrm{mas} ) among the events that have been found in the 2016-2019 observing seasons. These events include MOA-2017-BLG-147, MOA-2017-BLG-241, and MOA-2019-BLG-256, in which the first two events are produced by single lenses and the last event is produced by a binary lens. From the Monte Carlo simulations of Galactic events conducted with the combined ${t}_{{\rm{E}}} and ${\theta }_{{\rm{E}}} constraint, it is estimated that the lens masses of the individual events are ${0.051}_{-0.027}^{+0.100}\,{M}_{\odot }, ${0.044}_{-0.023}^{+0.090}\,{M}_{\odot }, and ${0.046}_{-0.023}^{+0.067}\,{M}_{\odot }/{0.038}_{-0.019}^{+0.056}\,{M}_{\odot } and the probability of the lens mass smaller than the lower limit of stars is ∼80% for all events. We point out that routine lens mass measurements of short-timescale lensing events require survey-mode space-based observations.
KMT-2018-BLG-0748Lb: sub-Saturn microlensing planet orbiting an ultracool hostHan, CheonghoShin, In-GuJung, Youn KilKim, DoeonYee, Jennifer C.Albrow, Michael D.Chung, Sun-JuGould, AndrewHwang, Kyu-HaLee, Chung-UkRyu, Yoon-HyunShvartzvald, YossiZang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.DOI: info:10.1051/0004-6361/202038173v. 641A105
Han, Cheongho, Shin, In-Gu, Jung, Youn Kil, Kim, Doeon, Yee, Jennifer C., Albrow, Michael D., Chung, Sun-Ju, Gould, Andrew, Hwang, Kyu-Ha, Lee, Chung-Uk, Ryu, Yoon-Hyun, Shvartzvald, Yossi, Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, and Pogge, Richard W. 2020. "KMT-2018-BLG-0748Lb: sub-Saturn microlensing planet orbiting an ultracool host." Astronomy and Astrophysics 641:A105. https://doi.org/10.1051/0004-6361/202038173
ID: 158793
Type: article
Authors: Han, Cheongho; Shin, In-Gu; Jung, Youn Kil; Kim, Doeon; Yee, Jennifer C.; Albrow, Michael D.; Chung, Sun-Ju; Gould, Andrew; Hwang, Kyu-Ha; Lee, Chung-Uk; Ryu, Yoon-Hyun; Shvartzvald, Yossi; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.
Abstract:
Aims: We announce the discovery of a microlensing planetary system, in which a sub-Saturn planet is orbiting an ultracool dwarf host.
Methods: We detected the planetary system by analyzing the short-timescale (tE ~ 4.4 days) lensing event KMT-2018-BLG-0748. The central part of the light curve exhibits asymmetry due to negative deviations in the rising side and positive deviations in the falling side.
Results: We find that the deviations are explained by a binary-lens model with a mass ratio between the lens components of q ~ 2 × 10-3. The short event timescale, together with the small angular Einstein radius, ?E ~ 0.11 mas, indicate that the mass of the planet host is very small. The Bayesian analysis conducted under the assumption that the planet frequency is independent of the host mass indicates that the mass of the planet is Mp = 0.18-0.10+0.29 MJ, and the mass of the host, Mh = 0.087-0.047+0.138 M?, is near the star-brown dwarf boundary, but the estimated host mass is sensitive to this assumption about the planet hosting probability. High-resolution follow-up observations would lead to revealing the nature of the planet host.
OGLE-2016-BLG-1227L: A Wide-separation Planet from a Very Short-timescale Microlensing EventHan, CheonghoUdalsk, AndrzejGould, AndrewAlbrow, Michael D.Chung, Sun-JuHwang, Kyu-HaJung, Youn KilLee, Chung-UkRyu, Yoon-HyunShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.Jee, M. JamesKim, DoeonKim, Chun-HweyKim, Woong-TaeMróz, PrzemekSzymański, Michał K.Skowron, JanPoleski, RadekSoszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofDOI: info:10.3847/1538-3881/ab6a9fv. 15991
Han, Cheongho, Udalsk, Andrzej, Gould, Andrew, Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Jung, Youn Kil, Lee, Chung-Uk, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Jee, M. James, Kim, Doeon, Kim, Chun-Hwey, Kim, Woong-Tae et al. 2020. "OGLE-2016-BLG-1227L: A Wide-separation Planet from a Very Short-timescale Microlensing Event." The Astronomical Journal 159:91. https://doi.org/10.3847/1538-3881/ab6a9f
ID: 156462
Type: article
Authors: Han, Cheongho; Udalsk, Andrzej; Gould, Andrew; Albrow, Michael D.; Chung, Sun-Ju; Hwang, Kyu-Ha; Jung, Youn Kil; Lee, Chung-Uk; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Jee, M. James; Kim, Doeon; Kim, Chun-Hwey; Kim, Woong-Tae; Mróz, Przemek; Szymański, Michał K.; Skowron, Jan; Poleski, Radek; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof
Abstract: We present the analysis of the microlensing event OGLE-2016-BLG-1227. The light curve of this short-duration event appears to be a single-lens event affected by severe finite-source effects. Analysis of the light curve based on a single-lens single-source (1L1S) model yields very small values of the event timescale, ${t}_{{\rm{E}}}\sim 3.5$ days, and the angular Einstein radius, ${\theta }_{{\rm{E}}}\sim 0.009$ mas, making the lens a candidate of a free-floating planet. Close inspection reveals that the 1L1S solution leaves small residuals with an amplitude of ∆I ≲ 0.03 mag. We find that the residuals are explained by the existence of an additional widely separated heavier lens component, indicating that the lens is a wide-separation planetary system rather than a free-floating planet. From Bayesian analysis, it is estimated that the planet has a mass of ${M}_{{\rm{p}}}={0.79}_{-0.39}^{+1.30}\,{M}_{{\rm{J}}}$ and it is orbiting a low-mass host star with a mass of ${M}_{\mathrm{host}}={0.10}_{-0.05}^{+0.17}\,{M}_{\odot }$ located with a projected separation of ${a}_{\perp }={3.4}_{-1.0}^{+2.1}$ au. The planetary system is located in the Galactic bulge with a line-of-sight separation from the source star of ${D}_{\mathrm{LS}}={1.21}_{-0.63}^{+0.96}$ kpc. The event shows that there is a range of deviations in the signatures of host stars for apparently isolated planetary lensing events and that it is possible to identify a host even when a deviation is subtle.
Four microlensing planets with faint-source stars identified in the 2016 and 2017 season dataHan, CheonghoUdalski, AndrzejKim, DoeonJung, Youn KilRyu, Yoon-HyunKMTNet CollaborationAlbrow, Michael D.Chung, Sun-JuGould, AndrewHwang, Kyu-HaLee, Chung-UkShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.Kim, Chun-HweyKim, Woong-TaeOGLE CollaborationMróz, PrzemekSzymanski, Michal K.Skowron, JanPoleski, RadekSoszynski, IgorPietrukowicz, PawelKozlowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykWrona, MarcinDOI: info:10.1051/0004-6361/202039066v. 642A110
Han, Cheongho, Udalski, Andrzej, Kim, Doeon, Jung, Youn Kil, Ryu, Yoon-Hyun, KMTNet Collaboration, Albrow, Michael D., Chung, Sun-Ju, Gould, Andrew, Hwang, Kyu-Ha, Lee, Chung-Uk, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Kim, Chun-Hwey, Kim, Woong-Tae et al. 2020. "Four microlensing planets with faint-source stars identified in the 2016 and 2017 season data." Astronomy and Astrophysics 642:A110. https://doi.org/10.1051/0004-6361/202039066
ID: 158786
Type: article
Authors: Han, Cheongho; Udalski, Andrzej; Kim, Doeon; Jung, Youn Kil; Ryu, Yoon-Hyun; KMTNet Collaboration; Albrow, Michael D.; Chung, Sun-Ju; Gould, Andrew; Hwang, Kyu-Ha; Lee, Chung-Uk; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Kim, Chun-Hwey; Kim, Woong-Tae; OGLE Collaboration; Mróz, Przemek; Szymanski, Michal K.; Skowron, Jan; Poleski, Radek; Soszynski, Igor; Pietrukowicz, Pawel; Kozlowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; Wrona, Marcin
Abstract:
Aims: Microlensing planets occurring on faint-source stars can escape detection due to their weak signals. Occasionally, detections of such planets are not reported due to the difficulty of extracting high-profile scientific issues on the detected planets.
Methods: For the solid demographic census of microlensing planetary systems based on a complete sample, we investigate the microlensing data obtained in the 2016 and 2017 seasons to search for planetary signals in faint-source lensing events. From this investigation, we find four unpublished microlensing planets: KMT-2016-BLG-2364Lb, KMT-2016-BLG-2397Lb, OGLE-2017-BLG-0604Lb, and OGLE-2017-BLG-1375Lb.
Results: We analyze the observed lensing light curves and determine their lensing parameters. From Bayesian analyses conducted with the constraints from the measured parameters, it is found that the masses of the hosts and planets are in the ranges 0.50 ? Mhost/M?? 0.85 and 0.5 ? Mp/MJ ? 13.2, respectively, indicating that all planets are giant planets around host stars with subsolar masses. The lenses are located in the distance range of 3.8 ? DL/kpc ? 6.4. It is found that the lenses of OGLE-2017-BLG-0604 and OGLE-2017-BLG-1375 are likely to be in the Galactic disk.
OGLE-2018-BLG-0677Lb: A Super-Earth Near the Galactic BulgeHerrera-Martín, AntonioAlbrow, M. D.Udalski, A.Gould, A.Ryu, Y. -HYee, Jennifer C.Chung, S. -JHan, C.Hwang, K. -HJung, Youn KilLee, C. -UShin, In-GuShvartzvald, Y.Zang, W.Cha, S. -MKim, D. -JKim, H. -WKim, S. -LLee, D. -JLee, Y.Park, B. -GPogge, R. W.KMTNet CollaborationSzymański, M. K.Mróz, P.Skowron, J.Poleski, R.Soszyński, I.Kozłowski, S.Pietrukowicz, P.Ulaczyk, K.Rybicki, K.Iwanek, P.Wrona, M.OGLE CollaborationDOI: info:10.3847/1538-3881/ab893ev. 159256
Herrera-Martín, Antonio, Albrow, M. D., Udalski, A., Gould, A., Ryu, Y. -H, Yee, Jennifer C., Chung, S. -J, Han, C., Hwang, K. -H, Jung, Youn Kil, Lee, C. -U, Shin, In-Gu, Shvartzvald, Y., Zang, W., Cha, S. -M, Kim, D. -J, Kim, H. -W, Kim, S. -L, Lee, D. -J, Lee, Y., Park, B. -G, Pogge, R. W., KMTNet Collaboration, Szymański, M. K., Mróz, P. et al. 2020. "OGLE-2018-BLG-0677Lb: A Super-Earth Near the Galactic Bulge." The Astronomical Journal 159:256. https://doi.org/10.3847/1538-3881/ab893e
ID: 156821
Type: article
Authors: Herrera-Martín, Antonio; Albrow, M. D.; Udalski, A.; Gould, A.; Ryu, Y. -H; Yee, Jennifer C.; Chung, S. -J; Han, C.; Hwang, K. -H; Jung, Youn Kil; Lee, C. -U; Shin, In-Gu; Shvartzvald, Y.; Zang, W.; Cha, S. -M; Kim, D. -J; Kim, H. -W; Kim, S. -L; Lee, D. -J; Lee, Y.; Park, B. -G; Pogge, R. W.; KMTNet Collaboration; Szymański, M. K.; Mróz, P.; Skowron, J.; Poleski, R.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Rybicki, K.; Iwanek, P.; Wrona, M.; OGLE Collaboration
Abstract: We report the analysis of the microlensing event OGLE-2018-BLG-0677. A small feature in the light curve of the event leads to the discovery that the lens is a star-planet system. Although there are two degenerate solutions that could not be distinguished for this event, both lead to a similar planet-host mass ratio. We perform a Bayesian analysis based on a Galactic model to obtain the properties of the system and find that the planet corresponds to a super-Earth/sub-Neptune with a mass of ${M}_{\mathrm{planet}}={3.96}_{-2.66}^{+5.88}{M}_{\oplus }$ . The host star has a mass of ${M}_{\mathrm{host}}={0.12}_{-0.08}^{+0.14}\,{M}_{\odot }$ . The projected separation for the inner and outer solutions are ${0.63}_{-0.17}^{+0.20}$ au and ${0.72}_{-0.19}^{+0.23}$ au respectively. At ${\rm{\Delta }}{\chi }^{2}={\chi }^{2}(1{\rm{L}}1{\rm{S}})-{\chi }^{2}(2{\rm{L}}1{\rm{S}})=46$ , this is by far the lowest ∆χ2 for any securely detected microlensing planet to date, a feature that is closely connected to the fact that it is detected primarily via a "dip" rather than a "bump."
OGLE-2017-BLG-0406: Spitzer Microlens Parallax Reveals Saturn-mass Planet Orbiting M-dwarf Host in the Inner Galactic DiskHirao, YukiBennett, David P.Ryu, Yoon-HyunKoshimoto, NaokiUdalski, AndrzejYee, Jennifer C.Sumi, TakahiroBond, Ian A.Shvartzvald, YossiAbe, FumioBarry, Richard K.Bhattacharya, AparnaDonachie, MartinFukui, AkihikoItow, YoshitakaKondo, IonaLi, Man Cheung AlexMatsubara, YutakaMatsuo, TaroMiyazaki, ShotaMuraki, YasushiNagakane, MasayukiRanc, ClémentRattenbury, Nicholas J.Suematsu, HarunoShibai, HiroshiSuzuki, DaisukeTristram, Paul J.Yonehara, AtsunoriMOA CollaborationSkowron, J.Poleski, R.Mróz, P.Szymański, M. K.Soszyński, I.Kozłowski, S.Pietrukowicz, P.Ulaczyk, K.Rybicki, K.Iwanek, P.OGLE CollaborationAlbrow, Michael D.Chung, Sun-JuGould, AndrewHan, CheonghoHwang, Kyu-HaJung, Youn KilShin, In-GuZang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.KMTNet CollaborationBeichman, Charles A.Bryden, GeofferyNovati, Sebastiano CalchiCarey, SeanGaudi, B. ScottHenderson, Calen B.Zhu, WeiSpitzer teamBachelet, EtienneBolt, GregChristie, GrantHundertmark, MarkusNatusch, TimMaoz, DanMcCormick, JennieStreet, Rachel A.Tan, Thiam-GuanTsapras, YiannisLCO and μFUN Follow-up TeamsJørgensen, U. G.Dominik, M.Bozza, V.Skottfelt, J.Snodgrass, C.Ciceri, S.Jaimes, R. FigueraEvans, D. F.Peixinho, N.Hinse, T. C.Burgdorf, M. J.Southworth, J.Rahvar, S.Sajadian, S.Rabus, M.von Essen, C.Fujii, Y. I.Campbell-White, J.Lowry, S.Helling, C.Mancini, L.Haikala, L.MiNDSTEp CollaborationKandori, RyoIRSF TeamDOI: info:10.3847/1538-3881/ab9ac3v. 16074
Hirao, Yuki, Bennett, David P., Ryu, Yoon-Hyun, Koshimoto, Naoki, Udalski, Andrzej, Yee, Jennifer C., Sumi, Takahiro, Bond, Ian A., Shvartzvald, Yossi, Abe, Fumio, Barry, Richard K., Bhattacharya, Aparna, Donachie, Martin, Fukui, Akihiko, Itow, Yoshitaka, Kondo, Iona, Li, Man Cheung Alex, Matsubara, Yutaka, Matsuo, Taro, Miyazaki, Shota, Muraki, Yasushi, Nagakane, Masayuki, Ranc, Clément, Rattenbury, Nicholas J., Suematsu, Haruno et al. 2020. "OGLE-2017-BLG-0406: Spitzer Microlens Parallax Reveals Saturn-mass Planet Orbiting M-dwarf Host in the Inner Galactic Disk." The Astronomical Journal 160:74. https://doi.org/10.3847/1538-3881/ab9ac3
ID: 158016
Type: article
Authors: Hirao, Yuki; Bennett, David P.; Ryu, Yoon-Hyun; Koshimoto, Naoki; Udalski, Andrzej; Yee, Jennifer C.; Sumi, Takahiro; Bond, Ian A.; Shvartzvald, Yossi; Abe, Fumio; Barry, Richard K.; Bhattacharya, Aparna; Donachie, Martin; Fukui, Akihiko; Itow, Yoshitaka; Kondo, Iona; Li, Man Cheung Alex; Matsubara, Yutaka; Matsuo, Taro; Miyazaki, Shota; Muraki, Yasushi; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Suematsu, Haruno; Shibai, Hiroshi; Suzuki, Daisuke; Tristram, Paul J.; Yonehara, Atsunori; MOA Collaboration; Skowron, J.; Poleski, R.; Mróz, P.; Szymański, M. K.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Rybicki, K.; Iwanek, P.; OGLE Collaboration; Albrow, Michael D.; Chung, Sun-Ju; Gould, Andrew; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Shin, In-Gu; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; KMTNet Collaboration; Beichman, Charles A.; Bryden, Geoffery; Novati, Sebastiano Calchi; Carey, Sean; Gaudi, B. Scott; Henderson, Calen B.; Zhu, Wei; Spitzer team; Bachelet, Etienne; Bolt, Greg; Christie, Grant; Hundertmark, Markus; Natusch, Tim; Maoz, Dan; McCormick, Jennie; Street, Rachel A.; Tan, Thiam-Guan; Tsapras, Yiannis; LCO and μFUN Follow-up Teams; Jørgensen, U. G.; Dominik, M.; Bozza, V.; Skottfelt, J.; Snodgrass, C.; Ciceri, S.; Jaimes, R. Figuera; Evans, D. F.; Peixinho, N.; Hinse, T. C.; Burgdorf, M. J.; Southworth, J.; Rahvar, S.; Sajadian, S.; Rabus, M.; von Essen, C.; Fujii, Y. I.; Campbell-White, J.; Lowry, S.; Helling, C.; Mancini, L.; Haikala, L.; MiNDSTEp Collaboration; Kandori, Ryo; IRSF Team
Abstract: We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the Spitzer satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of $q=7.0\times {10}^{-4}$ from the light-curve modeling. The ground-only and Spitzer-"only" data each provide very strong one-dimensional (1D) constraints on the 2D microlens parallax vector ${{\boldsymbol{\pi }}}_{{\rm{E}}}$ . When combined, these yield a precise measurement of ${{\boldsymbol{\pi }}}_{{\rm{E}}}$ and of the masses of the host ${M}_{\mathrm{host}}=0.56\pm 0.07\,{M}_{\odot }$ and planet Mplanet = 0.41 ± 0.05 MJup. The system lies at a distance DL = 5.2 ± 0.5 kpc from the Sun toward the Galactic bulge, and the host is more likely to be a disk population star according to the kinematics of the lens. The projected separation of the planet from the host is ${a}_{\perp }=3.5\pm 0.3\,\mathrm{au}$ (i.e., just over twice the snow line). The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the Gaia proper-motion measurement of the source suffers from a catastrophic 10σ error.
OGLE-2018-BLG-1269Lb: A Jovian Planet with a Bright I = 16 HostJung, Youn KilGould, AndrewUdalski, AndrzejSumi, TakahiroYee, Jennifer C.Han, CheonghoAlbrow, Michael D.Chung, Sun-JuHwang, Kyu-HaRyu, Yoon-HyunShin, In-GuShvartzvald, YossiZhu, WeiZang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.KMTNet CollaborationMróz, PrzemekSzymanski, Michal K.Skowron, JanPoleski, RadekSoszynski, IgorPietrukowicz, PawelKozlowski, SzymonUlaczyk, KrzystofRybicki, Krzysztof A.Iwanek, PatrykWrona, MarcinOGLE CollaborationAbe, FumioBarry, RichardBennett, David P.Bond, Ian A.Bhattacharya, AparnaDonachie, MartinFukui, AkihikoHirao, YukiItow, YoshitakaKondo, IonaKoshimoto, NaokiLi, Man Cheung AlexMatsubara, YutakaMiyazaki, ShotaMuraki, YasushiNagakane, MasayukiRanc, ClémentRattenbury, Nicholas J.Suematsu, HarunoSullivan, Denis J.Suzuki, DaisukeTristram, Paul J.Yonehara, AtsunoriMOA CollaborationDOI: info:10.3847/1538-3881/abacc8v. 160148
Jung, Youn Kil, Gould, Andrew, Udalski, Andrzej, Sumi, Takahiro, Yee, Jennifer C., Han, Cheongho, Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Zhu, Wei, Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., KMTNet Collaboration, Mróz, Przemek et al. 2020. "OGLE-2018-BLG-1269Lb: A Jovian Planet with a Bright I = 16 Host." The Astronomical Journal 160:148. https://doi.org/10.3847/1538-3881/abacc8
ID: 158877
Type: article
Authors: Jung, Youn Kil; Gould, Andrew; Udalski, Andrzej; Sumi, Takahiro; Yee, Jennifer C.; Han, Cheongho; Albrow, Michael D.; Chung, Sun-Ju; Hwang, Kyu-Ha; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Zhu, Wei; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; KMTNet Collaboration; Mróz, Przemek; Szymanski, Michal K.; Skowron, Jan; Poleski, Radek; Soszynski, Igor; Pietrukowicz, Pawel; Kozlowski, Szymon; Ulaczyk, Krzystof; Rybicki, Krzysztof A.; Iwanek, Patryk; Wrona, Marcin; OGLE Collaboration; Abe, Fumio; Barry, Richard; Bennett, David P.; Bond, Ian A.; Bhattacharya, Aparna; Donachie, Martin; Fukui, Akihiko; Hirao, Yuki; Itow, Yoshitaka; Kondo, Iona; Koshimoto, Naoki; Li, Man Cheung Alex; Matsubara, Yutaka; Miyazaki, Shota; Muraki, Yasushi; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Suematsu, Haruno; Sullivan, Denis J.; Suzuki, Daisuke; Tristram, Paul J.; Yonehara, Atsunori; MOA Collaboration
Abstract: We report the discovery of a planet in the microlensing event OGLE-2018-BLG-1269 with a planet-host mass ratio q ˜ 6 × 10-4, i.e., 0.6 times smaller than the Jupiter/Sun mass ratio. Combined with the Gaia parallax and proper motion, a strong one-dimensional constraint on the microlens parallax vector allows us to significantly reduce the uncertainties of lens physical parameters. A Bayesian analysis that ignores any information about light from the host yields that the planet is a cold giant $({M}_{2}={0.69}_{-0.22}^{+0.44}\,{M}_{{\rm{J}}})$ orbiting a Sun-like star $({M}_{1}={1.13}_{-0.35}^{+0.72}\,{M}_{\odot })$ at a distance of ${D}_{{\rm{L}}}={2.56}_{-0.62}^{+0.92}\,\mathrm{kpc}$ . The projected planet-host separation is ${a}_{\perp }={4.61}_{-1.17}^{+1.70}\,\mathrm{au}$ . Using Gaia astrometry, we show that the blended light lies $\lesssim 12\,\mathrm{mas}$ from the host and therefore must be either the host star or a stellar companion to the host. An isochrone analysis favors the former possibility at >99.6%. The host is therefore a subgiant. For host metallicities in the range of $0.0\leqslant [\mathrm{Fe}/{\rm{H}}]\leqslant +0.3$ , the host and planet masses are then in the range of $1.16\leqslant {M}_{1}/{M}_{\odot }\leqslant 1.38$ and $0.74\leqslant {M}_{2}/{M}_{{\rm{J}}}\leqslant 0.89$ , respectively. Low host metallicities are excluded. The brightness and proximity of the lens make the event a strong candidate for spectroscopic follow-up both to test the microlensing solution and to further characterize the system.
KMT-2019-BLG-0842Lb: A Cold Planet below the Uranus/Sun Mass RatioJung, Youn KilUdalski, AndrzejZang, WeichengBond, Ian A.Yee, Jennifer C.Han, CheonghoAlbrow, Michael D.Chung, Sun-JuGould, AndrewHwang, Kyu-HaRyu, Yoon-HyunShin, In-GuShvartzvald, YossiCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.KMTNet CollaborationMróz, PrzemekSzymanski, Michal K.Skowron, JanPoleski, RadekSoszynski, IgorPietrukowicz, PawelKozlowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykWrona, MarcinOGLE CollaborationAbe, FumioBarry, RichardBennett, David P.Bhattacharya, AparnaDonachie, MartinFujii, HirosameFukui, AkihikoHirao, YukiItow, YoshitakaKamei, YukeiKondo, IonaKoshimoto, NaokiLi, Man Cheung AlexMatsubara, YutakaMiyazaki, ShotaMuraki, YasushiNagakane, MasayukiRanc, ClémentRattenbury, Nicholas J.Satoh, YukiShoji, HikaruSuematsu, HarunoSullivan, Denis J.Sumi, TakahiroSuzuki, DaisukeTristram, Paul J.Yamakawa, TakeharuYamamwaki, TsubasaYonehara, AtsunoriMOA CollaborationDOI: info:10.3847/1538-3881/abbe93v. 160255
Jung, Youn Kil, Udalski, Andrzej, Zang, Weicheng, Bond, Ian A., Yee, Jennifer C., Han, Cheongho, Albrow, Michael D., Chung, Sun-Ju, Gould, Andrew, Hwang, Kyu-Ha, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., KMTNet Collaboration, Mróz, Przemek, Szymanski, Michal K. et al. 2020. "KMT-2019-BLG-0842Lb: A Cold Planet below the Uranus/Sun Mass Ratio." The Astronomical Journal 160:255. https://doi.org/10.3847/1538-3881/abbe93
ID: 158649
Type: article
Authors: Jung, Youn Kil; Udalski, Andrzej; Zang, Weicheng; Bond, Ian A.; Yee, Jennifer C.; Han, Cheongho; Albrow, Michael D.; Chung, Sun-Ju; Gould, Andrew; Hwang, Kyu-Ha; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; KMTNet Collaboration; Mróz, Przemek; Szymanski, Michal K.; Skowron, Jan; Poleski, Radek; Soszynski, Igor; Pietrukowicz, Pawel; Kozlowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; Wrona, Marcin; OGLE Collaboration; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Donachie, Martin; Fujii, Hirosame; Fukui, Akihiko; Hirao, Yuki; Itow, Yoshitaka; Kamei, Yukei; Kondo, Iona; Koshimoto, Naoki; Li, Man Cheung Alex; Matsubara, Yutaka; Miyazaki, Shota; Muraki, Yasushi; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Satoh, Yuki; Shoji, Hikaru; Suematsu, Haruno; Sullivan, Denis J.; Sumi, Takahiro; Suzuki, Daisuke; Tristram, Paul J.; Yamakawa, Takeharu; Yamamwaki, Tsubasa; Yonehara, Atsunori; MOA Collaboration
Abstract: We report the discovery of a cold planet with a very low planet/host mass ratio of q = (4.09 ± 0.27) × 10-5, which is similar to the ratio of Uranus/Sun (q = 4.37 × 10-5) in the solar system. The Bayesian estimates for the host mass, planet mass, system distance, and planet-host projected separation are Mhost = 0.76 ± 0.40M?, Mplanet = 10.3 ± 5.5M?, DL = 3.3 ± 1.3 kpc, and a? = 3.3 ± 1.4 au, respectively. The consistency of the color and brightness expected from the estimated lens mass and distance with those of the blend suggests the possibility that the most blended light comes from the planet host, and this hypothesis can be established if high-resolution images are taken during the next (2020) bulge season. We discuss the importance of conducting optimized photometry and aggressive follow-up observations for moderately or very high magnification events to maximize the detection rate of planets with very low mass ratios.
A Terrestrial-mass Rogue Planet Candidate Detected in the Shortest-timescale Microlensing EventMróz, PrzemekPoleski, RadoslawGould, AndrewUdalski, AndrzejSumi, TakahiroandSzymanski, Michal K.Soszynski, IgorPietrukowicz, PawelKozlowski, SzymonSkowron, JanUlaczyk, KrzysztofOGLE CollaborationAlbrow, Michael D.Chung, Sun-JuHan, CheonghoHwang, Kyu-HaJung, Youn KilKim, Hyoun-WooRyu, Yoon-HyunShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.KMT CollaborationDOI: info:10.3847/2041-8213/abbfadv. 903L11
Mróz, Przemek, Poleski, Radoslaw, Gould, Andrew, Udalski, Andrzej, Sumi, Takahiro, and, Szymanski, Michal K., Soszynski, Igor, Pietrukowicz, Pawel, Kozlowski, Szymon, Skowron, Jan, Ulaczyk, Krzysztof, OGLE Collaboration, Albrow, Michael D., Chung, Sun-Ju, Han, Cheongho, Hwang, Kyu-Ha, Jung, Youn Kil, Kim, Hyoun-Woo, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok et al. 2020. "A Terrestrial-mass Rogue Planet Candidate Detected in the Shortest-timescale Microlensing Event." The Astrophysical Journal 903:L11. https://doi.org/10.3847/2041-8213/abbfad
ID: 158836
Type: article
Authors: Mróz, Przemek; Poleski, Radoslaw; Gould, Andrew; Udalski, Andrzej; Sumi, Takahiro; and; Szymanski, Michal K.; Soszynski, Igor; Pietrukowicz, Pawel; Kozlowski, Szymon; Skowron, Jan; Ulaczyk, Krzysztof; OGLE Collaboration; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Kim, Hyoun-Woo; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; KMT Collaboration
Abstract: Some low-mass planets are expected to be ejected from their parent planetary systems during early stages of planetary system formation. According to planet formation theories, such as the core accretion theory, typical masses of ejected planets should be between 0.3 and 1.0 M?. Although in practice such objects do not emit any light, they may be detected using gravitational microlensing via their light-bending gravity. Microlensing events due to terrestrial-mass rogue planets are expected to have extremely small angular Einstein radii (?1 µas) and extremely short timescales (?0.1 day). Here, we present the discovery of the shortest-timescale microlensing event, OGLE-2016-BLG-1928, identified to date ( ${t}_{{\rm{E}}}\approx 0.0288\,\mathrm{day}=41.5\,\mathrm{minutes}$ ). Thanks to the detection of finite-source effects in the light curve of the event, we were able to measure the angular Einstein radius of the lens ${\theta }_{{\rm{E}}}=0.842\pm 0.064$ µas, making the event the most extreme short-timescale microlens discovered to date. Depending on its unknown distance, the lens may be a Mars- to Earth-mass object, with the former possibility favored by the Gaia proper motion measurement of the source. The planet may be orbiting a star but we rule out the presence of stellar companions up to the projected distance of ˜8.0 au from the planet. Our discovery demonstrates that terrestrial-mass free-floating planets can be detected and characterized using microlensing.
A Free-floating or Wide-orbit Planet in the Microlensing Event OGLE-2019-BLG-0551Mróz, PrzemekPoleski, RadosławHan, CheonghoUdalski, AndrzejGould, AndrewSzymański, Michał K.Soszyński, IgorPietrukowicz, PawełKozłowski, SzymonSkowron, JanUlaczyk, KrzysztofGromadzki, MariuszRybicki, KrzysztofIwanek, PatrykWrona, MarcinOGLE CollaborationAlbrow, Michael D.Chung, Sun-JuHwang, Kyu-HaRyu, Yoon-HyunJung, Youn KilShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.KMT CollaborationDOI: info:10.3847/1538-3881/ab8aebv. 159262
Mróz, Przemek, Poleski, Radosław, Han, Cheongho, Udalski, Andrzej, Gould, Andrew, Szymański, Michał K., Soszyński, Igor, Pietrukowicz, Paweł, Kozłowski, Szymon, Skowron, Jan, Ulaczyk, Krzysztof, Gromadzki, Mariusz, Rybicki, Krzysztof, Iwanek, Patryk, Wrona, Marcin, OGLE Collaboration, Albrow, Michael D., Chung, Sun-Ju, Hwang, Kyu-Ha, Ryu, Yoon-Hyun, Jung, Youn Kil, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng et al. 2020. "A Free-floating or Wide-orbit Planet in the Microlensing Event OGLE-2019-BLG-0551." The Astronomical Journal 159:262. https://doi.org/10.3847/1538-3881/ab8aeb
ID: 156816
Type: article
Authors: Mróz, Przemek; Poleski, Radosław; Han, Cheongho; Udalski, Andrzej; Gould, Andrew; Szymański, Michał K.; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Skowron, Jan; Ulaczyk, Krzysztof; Gromadzki, Mariusz; Rybicki, Krzysztof; Iwanek, Patryk; Wrona, Marcin; OGLE Collaboration; Albrow, Michael D.; Chung, Sun-Ju; Hwang, Kyu-Ha; Ryu, Yoon-Hyun; Jung, Youn Kil; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; KMT Collaboration
Abstract: High-cadence observations of the Galactic bulge by the microlensing surveys led to the discovery of a handful of extremely short-timescale microlensing events that can be attributed to free-floating or wide- orbit planets. Here, we report the discovery of another strong free- floating planet candidate, which was found from the analysis of the gravitational microlensing event OGLE-2019-BLG-0551. The light curve of the event is characterized by a very short duration (≲3 days) and a very small amplitude (≲0.1 mag). From modeling of the light curve, we find that the Einstein timescale, ${t}_{{\rm{E}}}=0.381\pm 0.017$ day, is much shorter, and the angular Einstein radius, ${\theta }_{{\rm{E}}}=4.35\pm 0.34$ μas, is much smaller than those of typical lensing events produced by stellar-mass lenses ( ${t}_{{\rm{E}}}\sim 20$ days, ${\theta }_{{\rm{E}}}\sim 0.3$ mas), indicating that the lens is very likely to be a planetary-mass object. We conduct an extensive search for possible signatures of a companion star in the light curve of the event, finding no significant evidence for the putative host star. For the first time, we also demonstrate that the angular Einstein radius of the lens does not depend on blending in the low-magnification events with strong finite source effects.
KMT-2018-BLG-1292: A Super-Jovian Microlens Planet in the Galactic PlaneRyu, Yoon-HyunNavarro, Maria GabrielaGould, AndrewAlbrow, Michael D.Chung, Sun-JuHan, CheonghoHwang, Kyu-HaJung, Youn KilShin, In-GuShvartzvald, YossiYee, Jennifer C.Zang, WeichengCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.Minniti, DanteSaito, Roberto K.Alonso-García, JavierPenny, Matthew T.DOI: info:10.3847/1538-3881/ab5e7ev. 15958
Ryu, Yoon-Hyun, Navarro, Maria Gabriela, Gould, Andrew, Albrow, Michael D., Chung, Sun-Ju, Han, Cheongho, Hwang, Kyu-Ha, Jung, Youn Kil, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zang, Weicheng, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., Minniti, Dante, Saito, Roberto K., Alonso-García, Javier, and Penny, Matthew T. 2020. "KMT-2018-BLG-1292: A Super-Jovian Microlens Planet in the Galactic Plane." The Astronomical Journal 159:58. https://doi.org/10.3847/1538-3881/ab5e7e
ID: 156219
Type: article
Authors: Ryu, Yoon-Hyun; Navarro, Maria Gabriela; Gould, Andrew; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; Minniti, Dante; Saito, Roberto K.; Alonso-García, Javier; Penny, Matthew T.
Abstract: We report the discovery of KMT-2018-BLG-1292Lb, a super-Jovian Mplanet = 5.0 ± 1.2 MJ planet orbiting an F or G dwarf Mhost = 1.2 ± 0.3 M, which lies physically within ${ \mathcal O }(10\,\mathrm{pc})$ of the Galactic plane. The source star is a heavily extincted AI ∼ 5.2 luminous giant that has the lowest Galactic latitude, b = −0°28, of any planetary microlensing event. The relatively blue blended light is almost certainly either the host or its binary companion, with the first explanation being substantially more likely. This blend dominates the light at the I band and completely dominates at the R and V bands. Hence, the lens system can be probed by follow-up observations immediately, i.e., long before the lens system and the source separate due to their relative proper motion. The system is well characterized despite the low cadence, Γ = 0.15─0.20 hr−1, of observations and short viewing windows near the end of the bulge season. This suggests that optical microlensing planet searches can be extended to the Galactic plane at relatively modest cost.
OGLE-2018-BLG-0532Lb: Cold Neptune with Possible Jovian SiblingRyu, Yoon-HyunUdalski, AndrzejYee, Jennifer C.Penny, Matthew T.Zang, WeichengAlbrow, Michael D.Chung, Sun-JuGould, AndrewHan, CheonghoHwang, Kyu-HaJung, Youn KilShin, In-GuShvartzvald, YossiCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.KMTNet CollaborationMróz, PrzemekSzymański, Michał K.Skowron, JanPoleski, RadekSoszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykWrona, MarcinOGLE CollaborationMao, ShudeFouque, PascalZhu, WeiWang, TianshuCFHT Microlensing CollaborationDOI: info:10.3847/1538-3881/abaa3fv. 160183
Ryu, Yoon-Hyun, Udalski, Andrzej, Yee, Jennifer C., Penny, Matthew T., Zang, Weicheng, Albrow, Michael D., Chung, Sun-Ju, Gould, Andrew, Han, Cheongho, Hwang, Kyu-Ha, Jung, Youn Kil, Shin, In-Gu, Shvartzvald, Yossi, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok, Park, Byeong-Gon, Pogge, Richard W., KMTNet Collaboration, Mróz, Przemek, Szymański, Michał K. et al. 2020. "OGLE-2018-BLG-0532Lb: Cold Neptune with Possible Jovian Sibling." The Astronomical Journal 160:183. https://doi.org/10.3847/1538-3881/abaa3f
ID: 158014
Type: article
Authors: Ryu, Yoon-Hyun; Udalski, Andrzej; Yee, Jennifer C.; Penny, Matthew T.; Zang, Weicheng; Albrow, Michael D.; Chung, Sun-Ju; Gould, Andrew; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Shin, In-Gu; Shvartzvald, Yossi; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.; KMTNet Collaboration; Mróz, Przemek; Szymański, Michał K.; Skowron, Jan; Poleski, Radek; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; Wrona, Marcin; OGLE Collaboration; Mao, Shude; Fouque, Pascal; Zhu, Wei; Wang, Tianshu; CFHT Microlensing Collaboration
Abstract: We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious signatures in the light curve that lead to an estimate of the planet-host mass ratio $q={M}_{\mathrm{planet}}/{M}_{\mathrm{host}}\simeq 1\times {10}^{-4}$ . Although there are no obvious systematic residuals to this double-lens/single-source (2L1S) fit, we find that χ2 can be significantly improved by adding either a third lens (3L1S, ∆χ2 = 81) or second source (2L2S, ∆χ2 = 77) to the lens-source geometry. After thorough investigation, we conclude that we cannot decisively distinguish between these two scenarios and therefore focus on the robustly detected planet. However, given the possible presence of a second planet, we investigate to what degree and with what probability such additional planets may affect seemingly single-planet light curves. Our best estimates for the properties of the lens star and the secure planet are a host mass M ∼ 0.25 M, system distance DL ∼ 1 kpc, and planet mass ${m}_{p,1}=8\,{M}_{\oplus }$ with projected separation ${a}_{1,\perp }=1.4\,\mathrm{au}$ . However, there is a relatively bright I = 18.6 (and also relatively blue) star projected within $\lt 50\,\mathrm{mas}$ of the lens, and if future high-resolution images show that this is coincident with the lens, then it is possible that it is the lens, in which case, the lens would be both more massive and more distant than the best-estimated values above.
KMT-2016-BLG-1836Lb: A Super-Jovian Planet from a High-cadence Microlensing FieldYang, HongjingZhang, XiangyuHwang, Kyu-HaZang, WeichengGould, AndrewWang, TianshuMao, ShudeAlbrow, Michael D.Chung, Sun-JuHan, CheonghoJung, Youn KilRyu, Yoon-HyunShin, In-GuShvartzvald, YossiYee, Jennifer C.Zhu, WeiPenny, Matthew T.Fouqué, PascalCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.DOI: info:10.3847/1538-3881/ab660ev. 15998
Yang, Hongjing, Zhang, Xiangyu, Hwang, Kyu-Ha, Zang, Weicheng, Gould, Andrew, Wang, Tianshu, Mao, Shude, Albrow, Michael D., Chung, Sun-Ju, Han, Cheongho, Jung, Youn Kil, Ryu, Yoon-Hyun, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zhu, Wei, Penny, Matthew T., Fouqué, Pascal, Cha, Sang-Mok, Kim, Dong-Jin, Kim, Hyoun-Woo, Kim, Seung-Lee, Lee, Chung-Uk, Lee, Dong-Joo, Lee, Yongseok et al. 2020. "KMT-2016-BLG-1836Lb: A Super-Jovian Planet from a High-cadence Microlensing Field." The Astronomical Journal 159:98. https://doi.org/10.3847/1538-3881/ab660e
ID: 156468
Type: article
Authors: Yang, Hongjing; Zhang, Xiangyu; Hwang, Kyu-Ha; Zang, Weicheng; Gould, Andrew; Wang, Tianshu; Mao, Shude; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Jung, Youn Kil; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zhu, Wei; Penny, Matthew T.; Fouqué, Pascal; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.
Abstract: We report the discovery of a super-Jovian planet in the microlensing event KMT-2016-BLG-1836, which was found by the Korea Microlensing Telescope Network (KMTNet) high-cadence observations ( ${\rm{\Gamma }}\sim 4\,{\mathrm{hr}}^{-1}$ ). The planet─host mass ratio q ∼ 0.004. A Bayesian analysis indicates that the planetary system is composed of a super-Jovian ${M}_{\mathrm{planet}}={2.2}_{-1.1}^{+1.9}{M}_{{\rm{J}}}$ planet orbiting an M or K dwarf, ${M}_{\mathrm{host}}={0.49}_{-0.25}^{+0.38}{M}_{\odot }$ , at a distance of ${D}_{{\rm{L}}}={7.1}_{-2.4}^{+0.8}$ kpc. The projected planet─host separation is ${3.5}_{-0.9}^{+1.1}$ au, implying that the planet is located beyond the snow line of the host star. Future high-resolution images can potentially strongly constrain the lens brightness and thus the mass and distance of the planetary system. Without considering detailed detection efficiency, selection, or publication biases, we find a potential mass-ratio desert at −3.7 ≲ log q ≲ −3.0 for the 31 published KMTNet planets.
Spitzer Microlensing Parallax Reveals Two Isolated Stars in the Galactic BulgeZang, WeichengShvartzvald, YossiWang, TianshuUdalski, AndrzejLee, Chung-UkSumi, TakahiroSkottfelt, JesperLi, Shun-ShengMao, ShudeZhu, WeiYee, Jennifer C.Calchi Novati, SebastianoBeichman, Charles A.Bryden, GeofferyCarey, SeanGaudi, B. ScottHenderson, Calen B.Spitzer teamMróz, PrzemekSkowron, JanPoleski, RadoslawSzymański, Michał K.Soszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofRybicki, Krzysztof A.Iwanek, PatrykOGLE CollaborationBachelet, EtienneChristie, GrantGreen, JonathanHennerley, SteveMaoz, DanNatusch, TimPogge, Richard W.Street, Rachel A.Tsapras, YiannisLCO Follow-Up TeamμFUN Follow-Up TeamAlbrow, Michael D.Chung, Sun-JuGould, AndrewHan, CheonghoHwang, Kyu-HaJung, Youn KilRyu, Yoon-HyunShin, In-GuCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Dong-JooLee, YongseokPark, Byeong-GonKMTNet CollaborationBond, Ian A.Abe, FumioBarry, RichardBennett, David P.Bhattacharya, AparnaDonachie, MartinFukui, AkihikoHirao, YukiItow, YoshitakaKondo, IonaKoshimoto, NaokiAlex Li, Man CheungMatsubara, YutakaMuraki, YasushiMiyazaki, ShotaNagakane, MasayukiRanc, ClémentRattenbury, Nicholas J.Suematsu, HarunoSullivan, Denis J.Suzuki, DaisukeTristram, Paul J.Yonehara, AtsunoriMOA CollaborationDominik, MartinHundertmark, MarkusJørgensen, Uffe G.Rahvar, SohrabSajadian, SedigheSnodgrass, ColinBozza, ValerioBurgdorf, Martin J.Evans, Daniel F.Figuera Jaimes, R.Fujii, Yuri I.Mancini, LuigiLonga-Peña, PenelopeHelling, ChristianePeixinho, NunoRabus, MarkusSouthworth, JohnUnda-Sanzana, EduardoVon Essen, CarolinaMiNDSTEp CollaborationDOI: info:10.3847/1538-4357/ab6ff8v. 8913
Zang, Weicheng, Shvartzvald, Yossi, Wang, Tianshu, Udalski, Andrzej, Lee, Chung-Uk, Sumi, Takahiro, Skottfelt, Jesper, Li, Shun-Sheng, Mao, Shude, Zhu, Wei, Yee, Jennifer C., Calchi Novati, Sebastiano, Beichman, Charles A., Bryden, Geoffery, Carey, Sean, Gaudi, B. Scott, Henderson, Calen B., Spitzer team, Mróz, Przemek, Skowron, Jan, Poleski, Radoslaw, Szymański, Michał K., Soszyński, Igor, Pietrukowicz, Paweł, Kozłowski, Szymon et al. 2020. "Spitzer Microlensing Parallax Reveals Two Isolated Stars in the Galactic Bulge." The Astrophysical Journal 891:3. https://doi.org/10.3847/1538-4357/ab6ff8
ID: 156385
Type: article
Authors: Zang, Weicheng; Shvartzvald, Yossi; Wang, Tianshu; Udalski, Andrzej; Lee, Chung-Uk; Sumi, Takahiro; Skottfelt, Jesper; Li, Shun-Sheng; Mao, Shude; Zhu, Wei; Yee, Jennifer C.; Calchi Novati, Sebastiano; Beichman, Charles A.; Bryden, Geoffery; Carey, Sean; Gaudi, B. Scott; Henderson, Calen B.; Spitzer team; Mróz, Przemek; Skowron, Jan; Poleski, Radoslaw; Szymański, Michał K.; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof; Rybicki, Krzysztof A.; Iwanek, Patryk; OGLE Collaboration; Bachelet, Etienne; Christie, Grant; Green, Jonathan; Hennerley, Steve; Maoz, Dan; Natusch, Tim; Pogge, Richard W.; Street, Rachel A.; Tsapras, Yiannis; LCO Follow-Up Team; μFUN Follow-Up Team; Albrow, Michael D.; Chung, Sun-Ju; Gould, Andrew; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Ryu, Yoon-Hyun; Shin, In-Gu; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; KMTNet Collaboration; Bond, Ian A.; Abe, Fumio; Barry, Richard; Bennett, David P.; Bhattacharya, Aparna; Donachie, Martin; Fukui, Akihiko; Hirao, Yuki; Itow, Yoshitaka; Kondo, Iona; Koshimoto, Naoki; Alex Li, Man Cheung; Matsubara, Yutaka; Muraki, Yasushi; Miyazaki, Shota; Nagakane, Masayuki; Ranc, Clément; Rattenbury, Nicholas J.; Suematsu, Haruno; Sullivan, Denis J.; Suzuki, Daisuke; Tristram, Paul J.; Yonehara, Atsunori; MOA Collaboration; Dominik, Martin; Hundertmark, Markus; Jørgensen, Uffe G.; Rahvar, Sohrab; Sajadian, Sedighe; Snodgrass, Colin; Bozza, Valerio; Burgdorf, Martin J.; Evans, Daniel F.; Figuera Jaimes, R.; Fujii, Yuri I.; Mancini, Luigi; Longa-Peña, Penelope; Helling, Christiane; Peixinho, Nuno; Rabus, Markus; Southworth, John; Unda-Sanzana, Eduardo; Von Essen, Carolina; MiNDSTEp Collaboration
Abstract: We report the mass and distance measurements of two single-lens events from the 2017 Spitzer microlensing campaign. The ground-based observations yield the detection of finite-source effects, and the microlens parallaxes are derived from the joint analysis of ground-based observations and Spitzer observations. We find that the lens of OGLE-2017-BLG-1254 is a 0.60 ± 0.03 M star with DLS = 0.53 ± 0.11 kpc, where DLS is the distance between the lens and the source. The second event, OGLE-2017-BLG-1161, is subject to the known satellite parallax degeneracy, and thus is either a 0.51-0.10+0.12 M_{☉} star with DLS = 0.40 ± 0.12 kpc or a 0.38-0.12+0.13 M_{☉} star with DLS = 0.53 ± 0.19 kpc. Both of the lenses are therefore isolated stars in the Galactic bulge. By comparing the mass and distance distributions of the eight published Spitzer finite-source events with the expectations from a Galactic model, we find that the Spitzer sample is in agreement with the probability of finite-source effects occurring in single-lens events.
OGLE-2015-BLG-1771Lb: A Microlens Planet Orbiting an Ultracool Dwarf?Zhang, XiangyuZang, WeichengUdalski, AndrzejGould, AndrewRyu, Yoon-HyunWang, TianshuYang, HongjingMao, ShudeMróz, PrzemekSkowron, JanPoleski, RadoslawSzymański, Michał K.Soszyński, IgorPietrukowicz, PawełKozłowski, SzymonUlaczyk, KrzysztofAlbrow, Michael D.Chung, Sun-JuHan, CheonghoHwang, Kyu-HaJung, Youn KilShin, In-GuShvartzvald, YossiYee, Jennifer C.Zhu, WeiCha, Sang-MokKim, Dong-JinKim, Hyoun-WooKim, Seung-LeeLee, Chung-UkLee, Dong-JooLee, YongseokPark, Byeong-GonPogge, Richard W.DOI: info:10.3847/1538-3881/ab6f6dv. 159116
Zhang, Xiangyu, Zang, Weicheng, Udalski, Andrzej, Gould, Andrew, Ryu, Yoon-Hyun, Wang, Tianshu, Yang, Hongjing, Mao, Shude, Mróz, Przemek, Skowron, Jan, Poleski, Radoslaw, Szymański, Michał K., Soszyński, Igor, Pietrukowicz, Paweł, Kozłowski, Szymon, Ulaczyk, Krzysztof, Albrow, Michael D., Chung, Sun-Ju, Han, Cheongho, Hwang, Kyu-Ha, Jung, Youn Kil, Shin, In-Gu, Shvartzvald, Yossi, Yee, Jennifer C., Zhu, Wei et al. 2020. "OGLE-2015-BLG-1771Lb: A Microlens Planet Orbiting an Ultracool Dwarf?." The Astronomical Journal 159:116. https://doi.org/10.3847/1538-3881/ab6f6d
ID: 156461
Type: article
Authors: Zhang, Xiangyu; Zang, Weicheng; Udalski, Andrzej; Gould, Andrew; Ryu, Yoon-Hyun; Wang, Tianshu; Yang, Hongjing; Mao, Shude; Mróz, Przemek; Skowron, Jan; Poleski, Radoslaw; Szymański, Michał K.; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Ulaczyk, Krzysztof; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zhu, Wei; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Hyoun-Woo; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W.
Abstract: We report the discovery and the analysis of the short ( ${t}_{{\rm{E}}}\lt 5$ days) planetary microlensing event, OGLE-2015-BLG-1771. The event was discovered by the Optical Gravitational Lensing Experiment, and the planetary anomaly (at I ∼ 19) was captured by The Korea Microlensing Telescope Network. The event has three surviving planetary models that explain the observed light curves, with planet-host mass ratio q ∼ 5.4 × 10−3, 4.5 × 10−3 and 4.5 × 10−2, respectively. The first model is the best-fit model, while the second model is disfavored by ∆χ2 ∼ 3. The last model is strongly disfavored by ∆χ2 ∼ 15 but not ruled out. A Bayesian analysis using a Galactic model indicates that the first two models are probably composed of a Saturn-mass planet orbiting a late M dwarf, while the third one could consist of a super-Jovian planet and a mid-mass brown dwarf. The source-lens relative proper motion is μrel ∼ 9 mas yr−1, so the source and lens could be resolved by current adaptive-optics instruments in 2020 if the lens is luminous.