Publication Date:
2019-06-26
Description:
We report the discovery of a super-Earth-mass planet in the microlensing event MOA-2012-BLG-505. This event has the second shortest event timescale of t(sub E) = 10 1 days where the observed data show evidence of a planetary companion. Our 15 minute high cadence survey observation schedule revealed the short subtle planetary signature. The system shows the well known close/wide degeneracy. The planet/host-star mass ratio is q = 2.1 10(exp 4) and the projected separation normalized by the Einstein radius is s = 1.1 or 0.9 for the wide and close solutions, respectively. We estimate the physical parameters of the system by using a Bayesian analysis and nd that the lens consists of a super-Earth with a mass of 6.7(sup +10.7)(sub -3.6) M orbiting around a brown dwarf or late-M-dwarf host with a mass of 0.10(sup +0.16)(sub -0.05) M with a projected starplanet separation of 0.9(sup +0.3)(sub -0.2) au. The system is at a distance of 7.2 1.1 kpc, i.e., it is likely to be in the Galactic bulge. The small angular Einstein radius ((sub E) = 0.12 0.02 mas) and short event timescale are typical for a low-mass lens in the Galactic bulge. Such low-mass planetary systems in the Bulge are rare because the detection efciency of planets in short microlensing events is relatively low. This discovery may suggest that such low-mass planetary systems are abundant in the Bulge and currently ongoing high cadence survey programs will detect more such events and may reveal an abundance of such planetary systems.
Keywords:
Astrophysics; Lunar and Planetary Science and Exploration
Type:
GSFC-E-DAA-TN64726
,
Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 154; 1; 35
Format:
text
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