1205.5835 (I. Boisse et al.)

The SOPHIE search for northern extrasolar planets. V. Follow-up of ELODIE candidates: Jupiter-analogues around Sun-like stars    [PDF]

I. Boisse, F. Pepe, C. Perrier, D. Queloz, X. Bonfils, F. Bouchy, N. C. Santos, L. Arnold, J. -L. Beuzit, R. F. Dìaz, X. Delfosse, A. Eggenberger, D. Ehrenreich, T. Forveille, G. Hébrard, A. -M. Lagrange, C. Lovis, M. Mayor, C. Moutou, D. Naef, A. Santerne, D. Ségransan, J. -P. Sivan, S. Udry

We present radial-velocity measurements obtained in a program to search for extrasolar planets with the spectrograph SOPHIE at the 1.93-m telescope of the Haute-Provence Observatory. Targets were selected from catalogs observed with ELODIE, mounted previously at the telescope, in order to detect long-period planets with an extended database close to 15 years. Two new Jupiter-analogue candidates are reported to orbit the bright stars HD150706 and HD222155 in 16.1 and 10.9 yr at 6.7 (+4.0,-1.4) and 5.1(+0.6,-0.7) AU. They respectively have minimum masses of 2.71 (+1.44,-0.66) and 1.90 (+0.67,-0.53) M_Jup. Using the measurements from ELODIE and SOPHIE, we refine the parameters of the long-period planets HD154345b and HD89307b, and publish the first reliable orbit for HD24040b. This last companion has a minimum mass of 4.01 +/- 0.49 M_Jup orbiting its star in 10.0 yr at 4.92 +/- 0.38 AU. Moreover, the data present evidence for a third bound object in the HD24040 system. With a surrounding dust debris disk, HD150706 is an active G0 dwarf for which we partially corrected the effect of the stellar spot on the SOPHIE radial-velocities. By contrast, HD222155 is an inactive G2V. In the SOPHIE measurements an instrumental effect could be characterized and partly corrected. Considering the work of Lovis et al. (2011b) and that we did not find significant correlation with the activity index in the SOPHIE data, the radial-velocity variations are not expected to come from stellar magnetic cycles. Finally, we discuss the main properties of this new population of long-period Jupiter-mass planets, for the moment, builds up of less than 20 candidates. These stars are preferential targets for direct-imaging or astrometry follow-up to constrain the system parameters and for higher precision radial-velocity to search for lower mass planets, aiming to find a Solar System twin.

View original: http://arxiv.org/abs/1205.5835