Limits on additional planetary companions to OGLE 2005-BLG-390L

作者：Kubas D^*; Cassan A; Dominik M; Bennett D P; Wambsganss J; Brillant S; Beaulieu J P; Albrow M D; Batista V; Bode M; Bramich D M; Burgdorf M; Caldwell J A R; Calitz H; Cook K H; Coutures Ch; Dieters S; Prester D Dominis; Donatowicz J; Fouque P; Greenhill J; Hill K; Hoffman M; Horne K; Jorgensen U G; Kains N; Kane S; Marquette J B; Martin R; Meintjes P; Menzies J; Pollard K R; Sahu K C; Snodgrass C; Steele I

来源：Astronomy & Astrophysics, 2008, 483(1): 317-324.

DOI：10.1051/0004-6361:20077449

• stars : planetary systems
• gravitational lensing

Aims. We investigate constraints on additional planets orbiting the distant M-dwarf star OGLE 2005-BLG-390L, around which photometric microlensing data has revealed the existence of the sub-Neptune-mass planet OGLE 2005-BLG-390Lb. We specifically aim to study potential Jovian companions and compare our findings with predictions from core-accretion and disc-instability models of planet formation. We also obtain an estimate of the detection probability for sub-Neptune mass planets similar to OGLE 2005-BLG 390Lb using a simplified simulation of a microlensing experiment.
Methods. We compute the efficiency of our photometric data for detecting additional planets around OGLE 2005-BLG-390L, as a function of the microlensing model parameters and convert it into a function of the orbital axis and planet mass by means of an adopted model of the Milky Way.
Results. We find that more than 50% of potential planets with a mass in excess of 1 M(J) between 1.1 and 2.3 AU around OGLE 2005-BLG-390L would have revealed their existence, whereas for gas giants above 3 MJ in orbits between 1.5 and 2.2 AU, the detection efficiency reaches 70%; however, no such companion was observed. Our photometric microlensing data therefore do not contradict the existence of gas giant planets at any separation orbiting OGLE 2005-BLG-390L. Furthermore we find a detection probability for an OGLE 2005-BLG-390Lb-like planet of around 2-5%. In agreement with current planet formation theories, this quantitatively supports the prediction that sub-Neptune mass planets are common around low-mass stars.

• 出版日期2008-5
• 单位中国地震局