A Cold Neptune-Mass Planet OGLE-2007-BLG-368Lb: Cold Neptunes Are Common
Creators: name: Sumi, T.
name: Bennett, D. P.
name: Bond, I. A.
name: Udalski, A.
name: Batista, V.
name: Dominik, M.
name: Fouqué, P.
name: Kubas, D.
name: Gould, A.
name: Macintosh, B.
name: Cook, K.
name: Dong, S.
name: Skuljan, L.
name: Cassan, A.
name: Collaboration, The MOA
name: :
name: Abe, F.
name: Botzler, C. S.
name: Fukui, A.
name: Furusawa, K.
name: Hearnshaw, J. B.
name: Itow, Y.
name: Kamiya, K.
name: Kilmartin, P. M.
name: Korpela, A.
name: Lin, W.
name: Ling, C. H.
name: Masuda, K.
name: Matsubara, Y.
name: Miyake, N.
name: Muraki, Y.
name: Nagaya, M.
name: Nagayama, T.
name: Ohnishi, K.
name: Okumura, T.
name: Perrott, Y. C.
name: Rattenbury, N.
name: Saito, To.
name: Sako, T.
name: Sullivan, D. J.
name: Sweatman, W. L.
name: P.
name: Yock, P. C. M.
name: Collaboration, The PLANET
name: :
name: Beaulieu, J. P.
name: Cole, A.
name: Coutures, Ch.
name: Duran, M. F.
name: Greenhill, J.
name: Jablonski, F.
name: Marboeuf, U.
name: Martioli, E.
name: Pedretti, E.
name: Pejcha, O.
name: Rojo, P.
name: Albrow, M. D.
name: Brillant, S.
name: Bode, M.
name: Bramich, D. M.
name: Burgdorf, M. J.
name: Caldwell, J. A. R.
name: Calitz, H.
name: Corrales, E.
name: Dieters, S.
name: Prester, D. Dominis
name: Donatowicz, J.
name: Hill, K.
name: Hoffman, M.
name: Horne, K.
name: J, U. G.
name: Kains, N.
name: Kane, S.
name: Marquette, J. B.
name: Martin, R.
name: Meintjes, P.
name: Menzies, J.
name: Pollard, K. R.
name: Sahu, K. C.
name: Snodgrass, C.
name: Steele, I.
name: Street, R.
name: Tsapras, Y.
name: Wambsganss, J.
name: Williams, A.
name: Zub, M.
name: Collaboration, The OGLE
name: :
name: Szyma, M. K.
name: Kubiak, M.
name: Pietrzy, G.
name: Soszy, I.
name: Szewczyk, O.
name: Ulaczyk, K.
name: Collaboration, The microFUN
name: :
name: Allen, W.
name: Christie, G. W.
name: DePoy, D. L.
name: Gaudi, B. S.
name: Han, C.
name: Janczak, J.
name: Lee, C. -U.
name: McCormick, J.
name: Mallia, F.
name: Monard, B.
name: Natusch, T.
name: Park, B. -G.
name: Pogge, R. W.
name: Santallo, R.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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 &lt; -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.
description: 39 pages, 10 figures, accepted for publication in ApJ