A Cold Neptune-Mass Planet OGLE-2007-BLG-368Lb: Cold Neptunes Are Common
Abstract
We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with a planet-star mass ratio of q=[9.5 +/- 2.1] x 10^{-5} via gravitational microlensing. The planetary deviation was detected in real-time thanks to the high cadence of the MOA survey, real-time light curve monitoring and intensive follow-up observations. A Bayesian analysis returns the stellar mass and distance at M_l = 0.64_{-0.26}^{+0.21} M_\sun and D_l = 5.9_{-1.4}^{+0.9} kpc, respectively, so the mass and separation of the planet are M_p = 20_{-8}^{+7} M_\oplus and a = 3.3_{-0.8}^{+1.4} AU, respectively. This discovery adds another cold Neptune-mass planet to the planetary sample discovered by microlensing, which now comprise four cold Neptune/Super-Earths, five gas giant planets, and another sub-Saturn mass planet whose nature is unclear. The discovery of these ten cold exoplanets by the microlensing method implies that the mass ratio function of cold exoplanets scales as dN_{\rm pl}/d\log q \propto q^{-0.7 +/- 0.2} with a 95% confidence level upper limit of n < -0.35 (where dN_{\rm pl}/d\log q \propto q^n). As microlensing is most sensitive to planets beyond the snow-line, this implies that Neptune-mass planets are at least three times more common than Jupiters in this region at the 95% confidence level.
Keywords
Cite
@article{arxiv.0912.1171,
title = {A Cold Neptune-Mass Planet OGLE-2007-BLG-368Lb: Cold Neptunes Are Common},
author = {T. Sumi and D. P. Bennett and I. A. Bond and A. Udalski and V. Batista and M. Dominik and P. Fouqué and D. Kubas and A. Gould and B. Macintosh and K. Cook and S. Dong and L. Skuljan and A. Cassan and The MOA Collaboration and : and F. Abe and C. S. Botzler and A. Fukui and K. Furusawa and J. B. Hearnshaw and Y. Itow and K. Kamiya and P. M. Kilmartin and A. Korpela and W. Lin and C. H. Ling and K. Masuda and Y. Matsubara and N. Miyake and Y. Muraki and M. Nagaya and T. Nagayama and K. Ohnishi and T. Okumura and Y. C. Perrott and N. Rattenbury and To. Saito and T. Sako and D. J. Sullivan and W. L. Sweatman and P. and P. C. M. Yock and The PLANET Collaboration and : and J. P. Beaulieu and A. Cole and Ch. Coutures and M. F. Duran and J. Greenhill and F. Jablonski and U. Marboeuf and E. Martioli and E. Pedretti and O. Pejcha and P. Rojo and M. D. Albrow and S. Brillant and M. Bode and D. M. Bramich and M. J. Burgdorf and J. A. R. Caldwell and H. Calitz and E. Corrales and S. Dieters and D. Dominis Prester and J. Donatowicz and K. Hill and M. Hoffman and K. Horne and U. G. J and N. Kains and S. Kane and J. B. Marquette and R. Martin and P. Meintjes and J. Menzies and K. R. Pollard and K. C. Sahu and C. Snodgrass and I. Steele and R. Street and Y. Tsapras and J. Wambsganss and A. Williams and M. Zub and The OGLE Collaboration and : and M. K. Szyma and M. Kubiak and G. Pietrzy and I. Soszy and O. Szewczyk and K. Ulaczyk and The microFUN Collaboration and : and W. Allen and G. W. Christie and D. L. DePoy and B. S. Gaudi and C. Han and J. Janczak and C. -U. Lee and J. McCormick and F. Mallia and B. Monard and T. Natusch and B. -G. Park and R. W. Pogge and R. Santallo},
journal= {arXiv preprint arXiv:0912.1171},
year = {2012}
}
Comments
39 pages, 10 figures, accepted for publication in ApJ