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MOA-2007-BLG-400 A super-Jupiter-mass planet orbiting a galactic bulge K-dwarf revealed by Keck adaptive optics imaging


Bhattacharya, A and Bennett, DP and Beaulieu, JP and Bond, IA and Koshimoto, N and Lu, JR and Blackman, JW and Vandorou, A and Terry, SK and Batista, V and Marquette, JB and Cole, AA and Fukui, A and Henderson, CB and Ranc, C, MOA-2007-BLG-400 A super-Jupiter-mass planet orbiting a galactic bulge K-dwarf revealed by Keck adaptive optics imaging, The Astronomical Journal, 162, (2) Article 60. ISSN 1538-3881 (2021) [Refereed Article]

Copyright Statement

© 2021. The American Astronomical Society.

DOI: doi:10.3847/1538-3881/abfec5


We present Keck/NIRC2 adaptive optics imaging of planetary microlensing event MOA-2007-BLG-400 that resolves the lens star system from the source. We find that the MOA-2007-BLG-400L planetary system consists of a 1.71 ± 0.27MJup planet orbiting a 0.69 ± 0.04M K-dwarf host star at a distance of 6.89 ± 0.77 kpc from the Sun. So, this planetary system probably resides in the Galactic bulge. The planet–host star projected separation is only weakly constrained due to the close-wide light-curve degeneracy; the 2σ projected separation ranges are 0.6–1.0 au and 4.7–7.7 au for close and wide solutions, respectively. This host mass is at the top end of the range of masses predicted by a standard Bayesian analysis. Our Keck follow-up program has now measured lens-source separations for six planetary microlensing events, and five of these six events have host star masses above the median prediction under the assumption that assumes that all stars have an equal chance of hosting planets detectable by microlensing. This suggests that more massive stars may be more likely to host planets of a fixed mass ratio that orbit near or beyond the snow line. These results also indicate the importance of host star mass measurements for exoplanets found by microlensing. The microlensing survey imaging data from NASA's Nancy Grace Roman Space Telescope (formerly WFIRST) mission will be doing mass measurements like this for a huge number of planetary events.

Item Details

Item Type:Refereed Article
Keywords:exoplanets, high-resolution microlensing event imaging, gravitational microlensing
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Stellar astronomy and planetary systems
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Beaulieu, JP (Dr Jean-Philippe Beaulieu)
UTAS Author:Blackman, JW (Mr Joshua Blackman)
UTAS Author:Vandorou, A ( Aikaterini Vandorou)
UTAS Author:Cole, AA (Professor Andrew Cole)
ID Code:145532
Year Published:2021
Funding Support:Australian Research Council (DP200101909)
Web of Science® Times Cited:6
Deposited By:Physics
Deposited On:2021-07-26
Last Modified:2021-09-02

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