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Combining Spitzer parallax and Keck II adaptive optics imaging to measure the mass of a solar-like star orbited by a cold gaseous planet discovered by microlensing


Beaulieu, J-P and Batista, V and Bennett, DP and Marquette, J-B and Blackman, JW and Cole, AA and Coutures, C and Danielski, C and Dominis Prester, D and Donatowicz, J and Fukui, A and Koshimoto, N and Loncaric, K and Morales, JC and Sumi, T and Suzuki, D and Henderson, C and Shvartzvald, Y and Beichman, C, Combining Spitzer parallax and Keck II adaptive optics imaging to measure the mass of a solar-like star orbited by a cold gaseous planet discovered by microlensing, Astronomical Journal, 155, (2) Article 78. ISSN 0004-6256 (2018) [Refereed Article]


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© 2018. The American Astronomical Society. All rights reserved.

DOI: doi:10.3847/1538-3881/aaa293


To obtain accurate mass measurements for cold planets discovered by microlensing, it is usually necessary to combine light curve modeling with at least two lens mass–distance relations. The physical parameters of the planetary system OGLE-2014-BLG-0124L have been constrained thanks to accurate parallax effect between ground-based and simultaneous space-based Spitzer observations. Here, we resolved the source+lens star from sub-arcsecond blends in H-band using adaptive optics (AO) observations with NIRC2 mounted on Keck II telescope. We identify additional flux, coincident with the source to within 160 mas. We estimate the potential contributions to this blended light (chance-aligned star, additional companion to the lens or to the source) and find that 85% of the NIR flux is due to the lens star at H L = 16.63 ± 0.06 and K L = 16.44 ± 0.06. We combined the parallax constraint and the AO constraint to derive the physical parameters of the system. The lensing system is composed of a mid-late type G main sequence star of M L = 0.9 ± 0.05 M located at D L = 3.5 ± 0.2 kpc in the Galactic disk. Taking the mass ratio and projected separation from the original study leads to a planet of M p = 0.65 ± 0.044 M Jupiter at 3.48 ± 0.22 au. Excellent parallax measurements from simultaneous ground-space observations have been obtained on the microlensing event OGLE-2014-BLG-0124, but it is only when they are combined with ~30 minutes of Keck II AO observations that the physical parameters of the host star are well measured.

Item Details

Item Type:Refereed Article
Keywords:exoplanets, detection, gravitational microlensing, planetary systems
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, J-P (Dr Jean-Philippe Beaulieu)
UTAS Author:Blackman, JW (Mr Joshua Blackman)
UTAS Author:Cole, AA (Professor Andrew Cole)
ID Code:130036
Year Published:2018
Web of Science® Times Cited:24
Deposited By:Mathematics and Physics
Deposited On:2019-01-08
Last Modified:2019-03-15
Downloads:73 View Download Statistics

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