CORALIE Survey Research Articles

Precise dynamical masses of new directly imaged companions from combining relative astrometry, radial velocities, and HIPPARCOS-Gaia eDR3 accelerations

Aims. With an observing time span of more than 20 yr, the CORALIE radial-velocity survey is able to detect long-term trends in data corresponding to companions with masses and separations accessible to direct imaging. Combining exoplanet detection techniques, such as radial velocities from the CORALIE survey, astrometric accelerations from HIPPARCOS and Gaia eDR3, and relative astrometry from direct imaging, removes the degeneracy of unknown orbital parameters. This allows precise model-independent masses of detected companions to be derived, which provides a powerful tool to test models of stellar and substellar mass-luminosity relations. Methods. Long-term precise Doppler measurements with the CORALIE spectrograph reveal radial-velocity signatures of companions on long-period orbits. The long baseline of radial-velocity data allows the detectability of the companion candidates to be assessed with direct imaging. We combine long-period radial-velocity data with absolute astrometry from HIPPARCOS and Gaia eDR3 and relative astrometry derived from new direct imaging detections with VLT/SPHERE to fit orbital parameters and derive precise dynamical masses of these companions. Results. In this paper we report the discovery of new companions orbiting HD 142234, HD 143616, and HIP 22059, as well as the first direct detection of HD 92987 B, and update the dynamical masses of two previously directly imaged companions: HD 157338 B and HD 195010 B. The companions span a period range of 32–279 yr and are all very low-mass stellar companions, ranging from 218 to 487 MJup. We compare the derived dynamical masses to mass-luminosity relations of very low-mass stars (<0.5 M⊙), and discuss the importance of using precursor radial-velocity and astrometric information to inform the future of high-contrast imaging of exoplanets and brown dwarfs.

The CORALIE survey for southern extrasolar planets

Context. Since 1998, a planet-search around main sequence stars within 50 pc in the southern hemisphere has been underway with the CORALIE spectrograph at La Silla Observatory. Aims. With an observing time span of more than 20 yr, the CORALIE survey is able to detect long-term trends in data with masses and separations large enough to select ideal targets for direct imaging. Detecting these giant companion candidates will allow us to start bridging the gap between radial-velocity-detected exoplanets and directly imaged planets and brown dwarfs. Methods. Long-term precise Doppler measurements with the CORALIE spectrograph reveal radial-velocity signatures of massive planetary companions and brown dwarfs on long-period orbits. Results. In this paper, we report the discovery of new companions orbiting HD 181234, HD 13724, HD 25015, HD 92987 and HD 50499. We also report updated orbital parameters for HD 50499b, HD 92788b and HD 98649b. In addition, we confirm the recent detection of HD 92788c. The newly reported companions span a period range of 15.6–40.4 yr and a mass domain of 2.93–26.77 MJup, the latter of which straddles the nominal boundary between planets and brown dwarfs. Conclusions. We report the detection of five new companions and updated parameters of four known extrasolar planets. We identify at least some of these companions to be promising candidates for imaging and further characterisation.

The CORALIE survey for southern extrasolar planets

Since 1998, a planet-search program around main sequence stars within 50 pc in the southern hemisphere, is carried out with the CORALIE echelle spectrograph at La Silla Observatory. With an observing time span of more than 14 years, the CORALIE survey is now able to unveil Jovian planets on Jupiter's period domain. This growing period-interval coverage is important regarding to formation and migration models since observational constraints are still weak for periods beyond the ice line. Long-term precise Doppler measurements with the CORALIE echelle spectrograph, together with a few additional observations made with the HARPS spectrograph on the ESO 3.6m telescope, reveal radial velocity signatures of massive planetary companions in long period orbits. In this paper we present seven new planets orbiting HD27631, HD98649, HD106515A, HD166724, HD196067, HD219077, and HD220689 together with the CORALIE orbital parameters for three already known planets around HD10647, HD30562, and HD86226. The period range of the new planetary companions goes from 2200 to 5500 days and covers a mass domain between 1 and 10.5 MJup. Surprisingly, five of them present quite high eccentricities above e>0.57. A pumping scenario by Kozai mechanism may be invoked for HD106515Ab and HD196067b which are both orbiting stars in multiple systems. As the presence of a third massive body can't be inferred from the data of HD98649b, HD166724b, and HD219077b, the origin of the eccentricity of these systems remains unknown. Except for HD10647b, no constraint on the upper mass of the planets is provided by Hipparcos astrometric data. Finally it is interesting to note that the hosts of these long period planets show no metallicity excess.

LOW-MASS COMPANIONS FOR FIVE SOLAR-TYPE STARS FROM THE MAGELLAN PLANET SEARCH PROGRAM

We report low mass companions orbiting five Solar-type stars that have emerged from the Magellan precision Doppler velocity survey, with minimum (Msini) masses ranging from 1.2 to 25 Mjup. These nearby target stars range from mildly metal-poor to metal-rich, and appear to have low chromospheric activity. The companions to the brightest two of these stars have previously been reported from the CORALIE survey. Four of these companions (HD 48265-b, HD 143361-b, HD 28185-b, HD 111232-b) are low-mass Jupiter-like planets in eccentric intermediate and long-period orbits. On the other hand, the companion to HD 43848 appears to be a long period brown dwarf in a very eccentric orbit.

The CORALIE survey for southern extra-solar planets

The CORALIE survey for southern extra-solar planets