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

D. Kubas , A. Cassan (1) , M. Dominik , D. P. Bennett , J. Wambsganss , S. Brillant , J. P. Beaulieu (2) , M. D. Albrow , V. Batista , M. Bode , D. M. Bramich , M. Burgdorf , J. A. R. Caldwell , H. Calitz , K. H. Cook , Ch. Coutures (2) , S. Dieters , D. Dominis Prester , J. Donatowicz , P. Fouqué (3) , J. Greenhill , K. Hill , M. Hoffman , K. Horne , U. G. Jørgensen , N. Kains , S. Kane , J. B. Marquette (2) , Roland Martin , P. Meintjes , J. Menzies , K. R. Pollard , K. C. Sahu , C. Snodgrass , I. Steele , Y. Tsapras , C. Vinter , A. Williams , K. Woller , M. Zub , The Planet/robonet Collaboration

1 ARI - Astronomische Rechen-Institut [Heidelberg]
2 IAP - Institut d'Astrophysique de Paris
3 LATT - Laboratoire Astrophysique de Toulouse-Tarbes

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 MJ 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.

Mots clés: stars: planetary systems; gravitational lensing

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

D. Kubas, A. Cassan, M. Dominik, D. P. Bennett, J. Wambsganss, et al.. Limits on additional planetary companions to OGLE 2005-BLG-390L. Astronomy and Astrophysics - A&A, 2008, 483, pp.317-324. ⟨10.1051/0004-6361:20077449⟩. ⟨hal-00277372⟩