A much lower density for the transiting extrasolar planet WASP-7
/ Authors
J. Southworth, Martin Dominik, U. G. Jørgensen, U. G. Jørgensen, S. Rahvar, C. Snodgrass, C. Snodgrass, Khalid Al-Subai, V. Bozza, V. Bozza
and 30 more authors
P. Browne, M. Burgdorf, S. C. Novati, P. Dodds, S. Dreizler, F. Finet, T. Gerner, S. Hardis, S. Hardis, K. Harpsoe, K. Harpsoe, C. Hellier, T. Hinse, T. Hinse, M. Hundertmark, N. Kains, N. Kains, E. Kerins, C. Liebig, L. Mancini, M. Mathiasen, M. Penny, S. Proft, D. Ricci, K. Sahu, G. Scarpetta, G. Scarpetta, S. Schäfer, F. Schönebeck, J. Surdej
/ Abstract
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 ; R Jup ) and much lower density (0.41 � 0.10 ? Jup versus ; ? Jup ) and surface gravity (13.4 � 2.6 m s -2 versus ; m s -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. Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla Observatory.Lightcurves data is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/527/A8
Journal: Astronomy and Astrophysics