A sub-Saturn Mass Planet, MOA-2009-BLG-319Lb
Creators: name: Miyake, N.
name: Sumi, T.
name: Dong, Subo
name: Street, R.
name: Mancini, L.
name: Gould, A.
name: Bennett, D. P.
name: Tsapras, Y.
name: Yee, J. C.
name: Albrow, M. D.
name: Bond, I. A.
name: Fouque, P.
name: Browne, P.
name: Han, C.
name: Snodgrass, C.
name: Finet, F.
name: Furusawa, K.
name: Harpsoe, K.
name: Allen, W.
name: Hundertmark, M.
name: Freeman, M.
name: Suzuki, D.
name: Abe, F.
name: Botzler, C. S.
name: Douchin, D.
name: Fukui, A.
name: Hayashi, F.
name: Hearnshaw, J. B.
name: Hosaka, S.
name: Itow, Y.
name: Kamiya, K.
name: Kilmartin, P. M.
name: Korpela, A.
name: Lin, W.
name: Ling, C. H.
name: Makita, S.
name: Masuda, K.
name: Matsubara, Y.
name: Muraki, Y.
name: Nagayama, T.
name: Nishimoto, K.
name: Ohnishi, K.
name: Perrott, Y. C.
name: Rattenbury, N.
name: Saito, To.
name: Skuljan, L.
name: Sullivan, D. J.
name: Sweatman, W. L.
name: Tristram, P. J.
name: Wada, K.
name: Yock, P. C. M.
name: Collaboration, The MOA
name: Bolt, G.
name: Bos, M.
name: Christie, G. W.
name: DePoy, D. L.
name: Drummond, J.
name: Gal-Yam, A.
name: Gaudi, B. S.
name: Gorbikov, E.
name: Higgins, D.
name: Janczak, K. -H. Hwang J.
name: Kaspi, S.
name: Lee, C. -U.
name: Koo, J. -R.
name: lowski, S. Koz
name: Lee, Y.
name: Mallia, F.
name: Maury, A.
name: Maoz, D.
name: McCormick, J.
name: Monard, L. A. G.
name: Moorhouse, D.
name: Mu~noz, J. A.
name: Natusch, T.
name: Ofek, E. O.
name: Pogge, R. W.
name: Polishook, D.
name: Santallo, R.
name: Shporer, A.
name: Spector, O.
name: Thornley, G.
name: Collaboration, The Micro FUN
name: Allan, A.
name: Bramich, D. M.
name: Horne, K.
name: Kains, N.
name: Steele, I.
name: Collaboration, The RoboNet
name: Bozza, V.
name: Burgdorf, M. J.
name: Novati, S. Calchi
name: Dominik, M.
name: Dreizler, S.
name: Glitrup, M.
name: Hessman, F. V.
name: Hinse, T. C.
name: Jorgensen, U. G.
name: Liebig, C.
name: Maier, G.
name: Mathiasen, M.
name: Rahvar, S.
name: Ricci, D.
name: Scarpetta, G.
name: Skottfelt, J.
name: Southworth, J.
name: Surdej, J.
name: Wambsganss, J.
name: Zimmer, F.
name: Consortium, The MiNDSTEp
name: Batista, V.
name: Beaulieu, J. P.
name: Brillant, S.
name: Cassan, A.
name: Cole, A.
name: Corrales, E.
name: Coutures, Ch.
name: Dieters, S.
name: Greenhill, J.
name: Kubas, D.
name: Menzies, J.
name: Collaboration, The PLANET
Publisher: name: arXiv
Year: 2010
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K or M-dwarf star in the inner Galactic disk or Galactic bulge. The high cadence observations of the MOA-II survey discovered this microlensing event and enabled its identification as a high magnification event approximately 24 hours prior to peak magnification. As a result, the planetary signal at the peak of this light curve was observed by 20 different telescopes, which is the largest number of telescopes to contribute to a planetary discovery to date. The microlensing model for this event indicates a planet-star mass ratio of q = (3.95 +/- 0.02) x 10^{-4} and a separation of d = 0.97537 +/- 0.00007 in units of the Einstein radius. A Bayesian analysis based on the measured Einstein radius crossing time, t_E, and angular Einstein radius, θ_E, along with a standard Galactic model indicates a host star mass of M_L = 0.38^{+0.34}_{-0.18} M_{Sun} and a planet mass of M_p = 50^{+44}_{-24} M_{Earth}, which is half the mass of Saturn. This analysis also yields a planet-star three-dimensional separation of a = 2.4^{+1.2}_{-0.6} AU and a distance to the planetary system of D_L = 6.1^{+1.1}_{-1.2} kpc. This separation is ~ 2 times the distance of the snow line, a separation similar to most of the other planets discovered by microlensing.
description: accepted to ApJ, 28 pages, 6 figures, 3 tables