Browsing by Author "Henderson CB"

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Kepler K2 Campaign 9 – II. First space-based discovery of an exoplanet using microlensing
(Oxford University Press, 2023-04-01) Specht D; Poleski R; Penny MT; Kerins E; McDonald I; Chung-Uk L; Udalski A; Bond IA; Shvartzvald Y; Zang W; Street RA; Hogg DW; Gaudi BS; Barclay T; Barentsen G; Howell SB; Mullally F; Henderson CB; Bryson ST; Caldwell DA; Haas MR; Van Cleve JE; Larson K; McCalmont K; Peterson C; Putnam D; Ross S; Packard M; Reedy L; Albrow MD; Sun-Ju C; Jung YK; Gould A; Han C; Kyu-Ha H; Yoon-Hyun R; In-Gu S; Yang H; Yee JC; Sang-Mok C; Dong-Jin K; Seung-Lee K; Dong-Joo L; Lee Y; Byeong-Gon P; Pogge RW; Szymański MK; Soszyński I; Ulaczyk K; Pietrukowicz P; Kozłowski SZ; Skowron J; Mróz P; Mao S; Fouqué P; Zhu W; Abe F; Barry R; Bennett DP; Bhattacharya A; Fukui A; Fujii H; Hirao Y; Itow Y; Kirikawa R; Kondo I; Koshimoto N; Matsubara Y; Matsumoto S; Miyazaki S; Muraki Y; Olmschenk G; Ranc C; Okamura A; Rattenbury NJ; Satoh Y; Sumi T; Suzuki D; Silva SI; Toda T; Tristram PJ; Vandorou A; Yama H; Beichman C; Bryden G; Novati SC
We present K2-2016-BLG-0005Lb, a densely sampled, planetary binary caustic-crossing microlensing event found from a blind search of data gathered from Campaign 9 of the Kepler K2 mission (K2C9). K2-2016-BLG-0005Lb is the first bound microlensing exoplanet discovered from space-based data. The event has caustic entry and exit points that are resolved in the K2C9 data, enabling the lens-source relative proper motion to be measured. We have fitted a binary microlens model to the Kepler data and to simultaneous observations from multiple ground-based surveys. Whilst the ground-based data only sparsely sample the binary caustic, they provide a clear detection of parallax that allows us to break completely the microlensing mass-position-velocity degeneracy and measure the planet’s mass directly. We find a host mass of 0.58 ± 0.04 M and a planetary mass of 1.1 ± 0.1 MJ. The system lies at a distance of 5.2 ± 0.2 kpc from Earth towards the Galactic bulge, more than twice the distance of the previous most distant planet found by Kepler. The sky-projected separation of the planet from its host is found to be 4.2 ± 0.3 au which, for circular orbits, deprojects to a host separation a = 4.4+−0149 au and orbital period P = 13+−29 yr. This makes K2-2016-BLG-0005Lb a close Jupiter analogue orbiting a low-mass host star. According to current planet formation models, this system is very close to the host mass threshold below which Jupiters are not expected to form. Upcoming space-based exoplanet microlensing surveys by NASA’s Nancy Grace Roman Space Telescope and, possibly, ESA’s Euclid mission, will provide demanding tests of current planet formation models.
OGLE-2015-BLG-0845L: a low-mass M dwarf from the microlensing parallax and xallarap effects
(Oxford University Press, 2024-09-01) Hu Z; Zhu W; Gould A; Udalski A; Sumi T; Chen P; Calchi Novati S; Yee JC; Beichman CA; Bryden G; Carey S; Fausnaugh M; Scott Gaudi B; Henderson CB; Shvartzvald Y; Wibking B; Mroz P; Skowron J; Poleski R; Szymanski MK; Soszynski I; Pietrukowicz P; Kozłowski S; Ulaczyk K; Rybicki KA; Iwanek P; Wrona M; Gromadzki MG; Abe F; Barry R; Bennett DP; Bhattacharya A; Bond IA; Fujii H; Fukui A; Hamada R; Hirao Y; Silva SI; Itow Y; Kirikawa R; Koshimoto N; Matsubara Y; Miyazaki S; Muraki Y; Olmschenk G; Ranc C; Rattenbury NJ; Satoh Y; Suzuki D; Tomoyoshi M; Tristram PJ; Vandorou A; Yama H; Yamashita K
We present the analysis of the microlensing event OGLE-2015-BLG-0845, which was affected by both the microlensing parallax and xallarap effects. The former was detected via the simultaneous observations from the ground and Spitzer, and the latter was caused by the orbital motion of the source star in a relatively close binary. The combination of these two effects led to a mass measurement of the lens object, revealing a low-mass (0.14 ± 0.05 M) M dwarf at the bulge distance (7.6 ± 1.0 kpc). The source binary consists of a late F-type subgiant and a K-type dwarf of ∼ 1.2 and ∼ 0.9M, respectively, and the orbital period is 70 ± 10 d. OGLE-2015-BLG-0845 is the first single-lens event in which the lens mass is measured via the binarity of the source. Given the abundance of binary systems as potential microlensing sources, the xallarap effect may not be a rare phenomenon. Our work thus highlights the application of the xallarap effect in the mass determination of microlenses, and the same method can be used to identify isolated dark lenses.
Systematic KMTNet planetary anomaly search: V. Complete sample of 2018 prime-field
(EDP Sciences, 2022-08-08) Gould A; Han C; Zang W; Yang H; Hwang K-H; Udalski A; Bond IA; Albrow MD; Chung S-J; Jung YK; Ryu Y-H; Shin I-G; Shvartzvald Y; Yee JC; Cha S-M; Kim D-J; Kim H-W; Kim S-L; Lee C-U; Lee D-J; Lee Y; Park B-G; Pogge RW; Mróz P; Szymanski MK; Skowron J; Poleski R; Soszyński I; Pietrukowicz P; Kozłowski S; Ulaczyk K; Rybicki KA; Iwanek P; Wrona M; Abe F; Barry R; Bennett DP; Bhattacharya A; Fujii H; Fukui A; Hirao Y; Silva SI; Kirikawa R; Kondo I; Koshimoto N; Matsubara Y; Matsumoto S; Miyazaki S; Muraki Y; Okamura A; Olmschenk G; Ranc C; Rattenbury NJ; Satoh Y; Sumi T; Suzuki D; Toda T; Tristram PJ; Vandorou A; Yama H; Beichman C; Bryden G; Novati SC; Gaudi BS; Henderson CB; Penny MT; Jacklin S; Stassun KG
We complete the analysis of all 2018 prime-field microlensing planets identified by the Korea Microlensing Telescope Network (KMTNet) Anomaly Finder. Among the ten previously unpublished events with clear planetary solutions, eight are either unambiguously planetary or are very likely to be planetary in nature: OGLE-2018-BLG-1126, KMT-2018-BLG-2004, OGLE-2018-BLG-1647, OGLE-2018-BLG-1367, OGLE-2018-BLG-1544, OGLE-2018-BLG-0932, OGLE-2018-BLG-1212, and KMT-2018-BLG-2718. Combined with the four previously published new Anomaly Finder events and 12 previously published (or in preparation) planets that were discovered by eye, this makes a total of 24 2018 prime-field planets discovered or recovered by Anomaly Finder. Together with a paper in preparation on 2018 subprime planets, this work lays the basis for the first statistical analysis of the planet mass-ratio function based on planets identified in KMTNet data. By systematically applying the heuristic analysis to each event, we identified the small modification in their formalism that is needed to unify the so-called close-wide and inner-outer degeneracies.