Parent stars of extrasolar planets - X. Lithium abundances and<i>v</i>sin <i>i</i>revisited

González, Guillermo; Carlson, M. K.; Tobin, Ryan Wesley

doi:10.1111/j.1365-2966.2009.16195.x

Cited by 99 publications

(111 citation statements)

References 20 publications

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“…Our derived lithium (Li) abundance for HD 219828 is log (Li) = 2.33 ± 0.04, similar to the value found by Gonzalez et al (2010) (log (Li) = 2.17 ± 0.06), and typical of early-G dwarfs. Planet-host stars with a temperature close to solar have been suggested to be Li-poor when compared with single field dwarfs of the same age and metallicity (for a recent paper and debate see Figueira et al 2014, and references therein).…”

Section: Hd 219828: the Starsupporting

confidence: 68%

“…The values are presented in Table 2. The derived effective temperature T eff = 5891 ± 18 K, log g = 4.19 ± 0.05 dex, and [Fe/H] = 0.19 ± 0.02 dex agree well with the spectral type listed in Hipparcos and also with other values from the literature: van Belle & von Braun (2009) derived a temperature of T eff = 5929 ± 90 from SED fitting, and Gonzalez et al (2010) derived T eff = 5861 ± 38 K and log g = 4.21 dex.…”

Section: Hd 219828: the Starsupporting

confidence: 60%

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An extreme planetary system around HD 219828

Santos

Santerne

Faria

et al. 2016

A&A

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Context. With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. This wide diversity provides fundamental clues to the processes of planet formation and evolution. Aims. We present a full investigation of the HD 219828 system, a bright metal-rich star for which a hot Neptune has previously been detected. Methods. We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD 219828. The spectra were used to characterise the star and its chemical abundances, as well as to check for spurious, activity induced signals. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. Results. We announce the discovery of a long period (P = 13.1 yr) massive (m sin i = 15.1 M Jup ) companion (HD 219828 c) in a very eccentric orbit (e = 0.81). The same data confirms the existence of a hot Neptune, HD 219828 b, with a minimum mass of 21 M ⊕ and a period of 3.83 days. The dynamical analysis shows that the system is stable, and that the equilibrium eccentricity of planet b is close to zero. Conclusions. The HD 219828 system is extreme and unique in several aspects. First, ammong all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like HD 219828, with a hot Neptune and a long-period massive companion are more frequent than similar systems with a hot Jupiter instead. This suggests that the formation of hot Neptunes follows a different path than the formation of their hot jovian counterparts. The high mass, long period, and eccentricity of HD 219828 c also make it a good target for Gaia astrometry as well as a potential target for atmospheric characterisation, using direct imaging or high-resolution spectroscopy. Astrometric observations will allow us to derive its real mass and orbital configuration. If a transit of HD 219828 b is detected, we will be able to fully characterise the system, including the relative orbital inclinations. With a clearly known mass, HD 219828 c may become a benchmark object for the range in between giant planets and brown dwarfs.

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Section: Hd 219828: the Starsupporting

confidence: 68%

Section: Hd 219828: the Starsupporting

confidence: 60%

An extreme planetary system around HD 219828

Santos

Santerne

Faria

et al. 2016

A&A

View full text Add to dashboard Cite

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“…Observations indicate that rapidly rotating stars preserve more Li than slow rotators of the same mass, as observed in Pleiades (Soderblom et al 1993;Garcia Lopez et al 1994) or IC 2602 (Randich et al 1997). This is also found in solar-type stars by Takeda et al (2010) and Gonzalez et al (2010). Other invoked mechanisms are internal waves (e.g.…”

Section: Introductionmentioning

confidence: 90%

“…Therefore, we removed from our sample of planet hosts some stars showing activity and/or with very young ages such as HD 81040, which has a disc (Sozzetti et al 2006); HD 70573 (Setiawan et al 2007); or (Arriagada et al 2010), and HD 219828 (Melo et al 2007). Some of these stars have been included by other authors (Gonzalez et al 2010;Ghezzi et al 2010;Ramírez et al 2012) in previous works about Li depletion and planets; however, we prefer to discard them since they are in different evolutionary stages. For instance, a subgiant with solar T eff had a higher temperature when it was on the MS and thus different Li content.…”

Section: Discussionmentioning

confidence: 99%

Li depletion in solar analogues with exoplanets

Delgado-Mena

Israelian

Hernández

et al. 2014

A&A

106

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Aims. We want to study the effects of the formation of planets and planetary systems on the atmospheric Li abundance of planet host stars. Methods. In this work we present new determinations of lithium abundances for 326 main sequence stars with and without planets in the T eff range 5600-5900 K. The 277 stars come from the HARPS sample, the remaining targets were observed with a variety of high-resolution spectrographs. Results. We confirm significant differences in the Li distribution of solar twins (T eff = T ± 80 K, log g = log g ± 0.2 and [Fe/H] = [Fe/H] ± 0.2): the full sample of planet host stars (22) shows Li average values lower than "single" stars with no detected planets (60). If we focus on subsamples with narrower ranges in metallicity and age, we observe indications of a similar result though it is not so clear for some of the subsamples. Furthermore, we compare the observed spectra of several couples of stars with very similar parameters that show differences in Li abundances up to 1.6 dex. Therefore we show that neither age, mass, nor metallicity of a parent star is the only cause for enhanced Li depletion in solar analogues. Conclusions. We conclude that another variable must account for that difference and suggest that this could be the presence of planets that causes additional rotationally induced mixing in the external layers of planet host stars. Moreover, we find indications that the amount of depletion of Li in planet-host solar-type stars is higher when the planets are more massive than Jupiter.

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“…Recent work by Gonzalez (2008), Gonzalez et al (2010), Castro et al (2008), and Israelian et al (2009) suggests a possible log Li -planet dependency, whereas Ryan (2000) and Luck & Heiter (2006) find that stars with planets show the same lithium distribution as the comparison field stars. Takeda et al (2007Takeda et al ( , 2010 describe the stellar angular momentum as the crucial factor that determines the lithium abundance of solar-like stars and find that slow rotators show an enhanced lithium depletion.…”

Section: Introductionmentioning

confidence: 99%

Lithium depletion in solar-like stars: no planet connection

Baumann

Ramírez

Meléndez³

et al. 2010

A&A

167

188

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We have determined precise stellar parameters and lithium abundances in a sample of 117 stars with basic properties very similar to the Sun. This sample selection reduces biasing effects and systematic errors in the analysis. We estimate the ages of our sample stars mainly from isochrone fitting but also from measurements of rotation period and X-ray luminosity and test the connection between lithium abundance, age, and stellar parameters. We find strong evidence for increasing lithium depletion with age. Our sample includes 14 stars that are known to host planets and it does not support recent claims that planet-host stars have experienced more lithium depletion than stars without planets. We find the solar lithium abundance normal for a star of its age, mass, and metallicity. Furthermore, we analyze published data for 82 stars that were reported to support an enhanced lithium depletion in planet hosts. We show that those stars in fact follow an age trend very similar to that found with our sample and that the presence of giant planets is not related to low lithium abundances. Finally, we discuss the systematic biases that led to the incorrect conclusion of an enhanced lithium depletion in planet-host stars.

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Parent stars of extrasolar planets - X. Lithium abundances andvsin irevisited

Cited by 99 publications

References 20 publications

An extreme planetary system around HD 219828

An extreme planetary system around HD 219828

Li depletion in solar analogues with exoplanets

Lithium depletion in solar-like stars: no planet connection

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