SIMBAD references

2018AJ....155..263S - Astron. J., 155, 263-263 (2018/June-0)

A likely detection of a two-planet system in a low-magnification microlensing event.

SUZUKI D., BENNETT D.P., UDALSKI A., BOND I.A., SUMI T., HAN C., KIM H.-I., ABE F., ASAKURA Y., BARRY R.K., BHATTACHARYA A., DONACHIE M., FREEMAN M., FUKUI A., HIRAO Y., ITOW Y., KOSHIMOTO N., LI M.C.A., LING C.H., MASUDA K., MATSUBARA Y., MURAKI Y., NAGAKANE M., ONISHI K., OYOKAWA H., RANC C., RATTENBURY N.J., SAITO T., SHARAN A., SULLIVAN D.J., TRISTRAM P.J., YONEHARA A. (The MOA Collaboration), POLESKI R., MROZ P., SKOWRON J., SZYMANSKI M.K., SOSZYNSKI I., KOZLOWSKI S., PIETRUKOWICZ P., WYRZYKOWSKI L., ULACZYK K. (The OGLE Collaboration)

Abstract (from CDS):

We report on the analysis of a microlensing event, OGLE-2014-BLG-1722, that showed two distinct short-term anomalies. The best-fit model to the observed light curves shows that the two anomalies are explained with two planetary mass ratio companions to the primary lens. Although a binary-source model is also able to explain the second anomaly, it is marginally ruled out by 3.1σ. The two-planet model indicates that the first anomaly was caused by planet "b" with a mass ratio of q=(4.5–0.6+0.7)×10–4 and projected separation in units of the Einstein radius, s = 0.753 ± 0.004. The second anomaly reveals planet "c" with a mass ratio of q2=(7.0–1.7+2.3)×10–4 with Δχ2 ∼ 170 compared to the single-planet model. Its separation has two degenerated solutions: the separation of planet c is s2 = 0.84 ± 0.03 and 1.37 ± 0.04 for the close and wide models, respectively. Unfortunately, this event does not show clear finite-source and microlensing parallax effects; thus, we estimated the physical parameters of the lens system from Bayesian analysis. This gives the masses of planets b and c as mb=56–33+51 and mc=85–51+86M, respectively, and they orbit a late-type star with a mass of Mhost=0.40–0.24+0.36M located at DL=6.4–1.8+1.3kpc from us. The projected distances between the host and planets are r_⊥,b_=1.5±0.6au for planet b and r_⊥,c=1.7-0.6_+0.7au and r_⊥,c=2.7-1.0_+1.1au for the close and wide models of planet c. If the two-planet model is true, then this is the third multiple-planet system detected using the microlensing method and the first multiple-planet system detected in low-magnification events, which are dominant in the microlensing survey data. The occurrence rate of multiple cold gas giant systems is estimated using the two such detections and a simple extrapolation of the survey sensitivity of the 6 yr MOA microlensing survey combined with the 4 yr µFUN detection efficiency. It is estimated that 6% ± 2% of stars host two cold giant planets.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

Journal keyword(s): gravitational lensing: micro - planetary systems

Simbad objects: 16

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