OGLE-2017-BLG-1049: Another giant planet microlensing event

Abstract

We report a giant exoplanet discovery in the microlensing event OGLE-2017-BLG-1049, which is a planet-host star mass ratio of $q=9.53\pm 0.39\times 10^{-3}$ and has a caustic crossing feature in the Korea Microlensing Telescope Network (KMTNet) observations. The caustic crossing feature yields an angular Einstein radius of $\hat{I}{¸}_{\mathrm{E}}=0.52\pm 0.11\mathrm{mas}$. However, the microlens parallax is not measured because of the time scale of the event $t_{\mathrm{E}}\simeq 29\mathrm{days}$, which is not long enough in this case to determine the microlens parallax. Thus, we perform a Bayesian analysis to estimate physical quantities of the lens system. From this, we find that the lens system has a star with mass $M_{\mathrm{h}}=0.55_{-0.29}^{+0.36}{M}_{\odot }$ hosting a giant planet with $M_{\mathrm{p}}=5.53_{-2.87}^{+3.62}{M}_{\mathrm{Jup}}$, at a distance of $D_{\mathrm{L}}=5.67_{-1.52}^{+1.11}\mathrm{kpc}$. The projected star-planet separation in units of the Einstein radius $(\hat{I}{¸}_{\mathrm{E}})$ corresponding to the total mass of the lens system is $a_{\perp }=3.92_{-1.32}^{+1.10}\mathrm{au}$. This means that the planet is located beyond the snow line of the host. The relative lens-source proper motion is $\hat{I}{¼}_{\mathrm{rel}}\sim 7\mathrm{mas}\mathrm{y}{\mathrm{r}}^{-1}$, thus the lens and source will be separated from each other within 10 years. Then the flux of the host star can be measured by a 30m class telescope with high-resolution imaging in the future, and thus its mass can be determined.

7 figures, Published in Journal of the Korean Astronomical Society(JKAS)