Planetary companions around the K giant stars 11 Ursae Minoris and HD 32518

Döllinger, M. P.; Hatzes, A. P.; Pasquini, L.; Guenther, E. W.; Hartmann, Michael

doi:10.1051/0004-6361/200911702

Cited by 55 publications

(64 citation statements)

References 39 publications

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“…As for other planets around giant stars, HD 1690 b is a massive gaseous planet, similar to the recently discovered HD 32518 b (Döllinger et al 2009). There are now about 20 known planetary systems to giant stars, all with semi-major axes exceeding 0.59 AU and minimum masses larger than 1.5 M Jup .…”

Section: Resultssupporting

confidence: 74%

“…3 to 5 of Sousa et al (2008). The stellar luminosity was calculated based on Hipparcos photometry (ESA 1997) and revised Hipparcos parallaxes (van Leeuwen 2007), including the bolometric correction as calibrated in Flower (1996). Theoretical evolutionary tracks are compared with the measured values to estimate the mass, radius and age of the stars with a Bayesian analysis 1 (da Silva et al 2006).…”

Section: Characteristics Of the Host Starsmentioning

confidence: 99%

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The HARPS search for southern extra-solar planets

Moutou

Mayor

Curto³

et al. 2011

A&A

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We are conducting a planet search survey with HARPS since seven years. The volume-limited stellar sample includes all F2 to M0 main-sequence stars within 57.5 pc, where extrasolar planetary signatures are systematically searched for with the radial-velocity technics. In this paper, we report the discovery of new substellar companions of seven main-sequence stars and one giant star, detected through multiple Doppler measurements with the instrument HARPS installed on the ESO 3.6 m telescope, La Silla, Chile. These extrasolar planets orbit the stars HD 1690, HD 25171, HD 33473A, HD 89839, HD 113538, HD 167677, and HD 217786. The alreadypublished giant planet around HD 72659 is also analysed here, and its elements are better determined by the addition of HARPS and Keck data. The other discoveries are giant planets in distant orbits, ranging from 0.3 to 29 M Jup in mass and between 0.7 and 10 years in orbital period. The low metallicity of most of these new planet-hosting stars reinforces the current trend for long-distance planets around metal-poor stars. Long-term radial-velocity surveys allow probing the outskirts of extrasolar planetary systems, although confidence in the solution may be low until more than one orbital period is fully covered by the observations. For many systems discussed in this paper, longer baselines are necessary to refine the radial-velocity fit and derive planetary parameters. The radial-velocity time series of stars BD -114672 and HIP 21934 are also analysed and their behaviour interpreted in terms of the activity cycle of the star, rather than long-period planetary companions.

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Section: Resultssupporting

confidence: 74%

Section: Characteristics Of the Host Starsmentioning

confidence: 99%

The HARPS search for southern extra-solar planets

Moutou

Mayor

Curto³

et al. 2011

A&A

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“…However, some recent programs have been monitoring also more massive stars, such as evolved subgiants and giants (e.g., Hatzes et al 2006;Döllinger et al 2009;Niedzielski et al 2009;Johnson et al 2011;Sato et al 2013) as well as A-F-type mainsequence stars (e.g., Galland et al 2005;Guenther et al 2009;Hartmann et al 2010;Borgniet et al 2014). One of our targets was the roAp star HD 42659.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

A radial-velocity survey of Ap stars with HARPS

Hartmann

Hatzes

2015

A&A

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Context. Chemically peculiar Ap stars are main-sequence stars of spectral type B8-F3 which show large overabundances of some chemical elements (e.g., Si, Sr, Cr), especially of rare-earth elements, compared to normal A-type stars. Furthermore, they have strong, global magnetic fields and low rotational velocities. Some Ap stars exhibit high-overtone, low-degree, non-radial p-mode pulsations with periods of 6-24 min and are called rapidly oscillating Ap (roAp) stars. Interestingly, no roAp star is known to be a spectroscopic binary (SB), while many non-oscillating Ap (noAp) stars are found in SB systems. Aims. The goal of this survey was to carry out a systematic search for sub-stellar and stellar companions around Ap stars. Methods. Between 2004 and 2009, we observed 65 chemically peculiar stars with the HARPS spectrograph at the 3.6-m telescope at the European Southern Observatory (La Silla, Chile). The radial-velocity (RV) measurements were obtained using a new software called HARPS-TERRA which is based on a least-squares matching of each individual spectrum to a high signal-to-noise ratio template for each star. Results. We find significant variability with a period of 93.2 days and a semi-amplitude of 11.85 km s −1 in the RVs of HD 42659, a star of our sample that belongs to the group of roAp stars. This variability is caused by a stellar companion with a minimum mass of 0.47 M in a slightly eccentric (e = 0.146) orbit at a separation of 0.55 AU.Conclusions. This detection makes HD 42659 the first confirmed SB around a roAp star in a relatively close orbit. It shows that tidal interactions in binaries do not necessarily inhibit pulsations in Ap stars.

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“…In particular, their A&A 566, A113 (2014) occurrence rate is higher and they are on average more massive (Döllinger et al 2009). This observational result is supported by theoretical studies that predict an increase in the frequency of giant planets with the mass of the host star (e.g., Kennedy & Kenyon 2008).…”

Section: Introductionmentioning

confidence: 99%

The properties of planets around giant stars

Jones

Jenkins

Bluhm

et al. 2014

A&A

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Context. More than 50 exoplanets have been found around giant stars, revealing different properties when compared to planets orbiting solar-type stars. In particular, they are super-Jupiters and are not found orbiting interior to ∼0.5 AU. Aims. We are conducting a radial velocity study of a sample of 166 giant stars aimed at studying the population of close-in planets orbiting giant stars and how their orbital and physical properties are influenced by the post-MS evolution of the host star. Methods. We have collected multiepoch spectra for all of the targets in our sample. We have computed precision radial velocities from FECH/CHIRON and FEROS spectra, using the I 2 cell technique and the simultaneous calibration method, respectively. Results. We present the discovery of a massive planet around the giant star HIP 105854. The best Keplerian fit to the data leads to an orbital distance of 0.81 ± 0.03 AU, an eccentricity of 0.02 ± 0.03 and a projected mass of 8.2 ± 0.2 M J . With the addition of this new planet discovery, we performed a detailed analysis of the orbital properties and mass distribution of the planets orbiting giant stars. We show that there is an overabundance of planets around giant stars with a ∼ 0.5−0.9 AU, which might be attributed to tidal decay. Additionally, these planets are significantly more massive than those around MS and subgiant stars, suggesting that they grow via accretion either from the stellar wind or by mass transfer from the host star. Finally, we show that planets around evolved stars have lower orbital eccentricities than those orbiting solar-type stars, which suggests that they are either formed in different conditions or that their orbits are efficiently circularized by interactions with the host star.

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Planetary companions around the K giant stars 11 Ursae Minoris and HD 32518

Cited by 55 publications

References 39 publications

The HARPS search for southern extra-solar planets

The HARPS search for southern extra-solar planets

A radial-velocity survey of Ap stars with HARPS

The properties of planets around giant stars

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