A much lower density for the transiting extrasolar planet WASP-7

作者：Southworth J^*; Dominik M; Jorgensen U G; Rahvar S; Snodgrass C; Alsubai K; Bozza V; Browne P; Burgdorf M; Novati S Calchi; Dodds P; Dreizler S; Finet F; Gerner T; Hardis S; Harpsoe K; Hellier C; Hinse T C; Hundertmark M; Kains N; Kerins E; Liebig C; Mancini L; Mathiasen M; Penny M T; Proft S; Ricci D; Sahu K; Scarpetta G; Schaefer S; Schoenebeck F; Surdej J

来源：Astronomy & Astrophysics, 2011, 527: A8.

DOI：10.1051/0004-6361/201016183

• planets and satellites: fundamental parameters
• planetary systems
• stars: individual: WASP-7

We present the first high-precision photometry of the transiting extrasolar planetary system WASP-7, obtained using telescope defocussing techniques and reaching a scatter of 0.68 mmag per point. We find that the transit depth is greater and that the host star is more evolved than previously thought. The planet has a significantly larger radius (1.330 +/- 0.093 R(Jup) versus 0.915(-0.040)(+0.046) R(Jup)) and much lower density (0.41 +/- 0.10 rho(Jup) versus 1.26(-0.21)(+0.25) rho(Jup)) and surface gravity (13.4 +/- 2.6 ms(-2) versus 26.4(-4.0)(+4.4) ms(-2)) than previous measurements showed. Based on the revised properties it is no longer an outlier in planetary mass-radius and period-gravity diagrams. We also obtain a more precise transit ephemeris for the WASP-7 system.

• 出版日期2011-3
• 单位中国地质博物馆