Article

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

Astronomy and Astrophysics (Impact Factor: 5.08). 05/2012; DOI: 10.1051/0004-6361/201118419
Source: arXiv

ABSTRACT We present radial-velocity measurements obtained in a programs underway 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-analog 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 and to
have minimum masses of 2.71 (+1.44,-0.66) and 1.90 (+0.67,-0.53) M_Jup,
respectively. 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 provide evidence of 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. HD222155 is an inactive G2V star. On the basis of the
previous findings of Lovis and collaborators and since no significant
correlation between the radial-velocity variations and the activity index are
found in the SOPHIE data, these variations are not expected to be only due to
stellar magnetic cycles. Finally, we discuss the main properties of this new
population of long-period Jupiter-mass planets, which for the moment, consists
of fewer than 20 candidates. These stars are preferential targets either 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.

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