Dwarfs in the Local Region

Luck, R. E.; Heiter, U.

doi:10.1086/504080

Cited by 137 publications

(195 citation statements)

References 32 publications

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“…τ Boo was noted as a metal-rich star according to the criterion [Fe/H] > 0.2. Subsequently, the high metallicity of our target was confirmed by several accurate abundance analyses, the most recent performed by Ecuvillon et al (2004b), Valenti & Fischer (2005), Takeda & Honda (2005), Gilli et al (2006), Luck &Heiter (2006), andTakeda (2007).…”

Section: Photospheric Abundancesmentioning

confidence: 57%

Photospheric and coronal abundances in solar-type stars: the peculiar case ofτ Bootis

Maggio

Sanz-Forcada

2011

A&A

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Aims. Chemical abundances in solar-type stars are still a much debated topic in many respects. In particular, planet-hosting stars are known to be metal-rich, but whether or not this peculiarity applies also to the chemical composition of the outer stellar atmospheres is still to be clarified. More in general, coronal and photospheric abundances in late-type stars appear to be different in many cases, but understanding how chemical stratification effects work in stellar atmospheres requires an observational base larger than currently available. Methods. We obtained XMM-Newton high-resolution X-ray spectra of τ Bootis, a well known nearby star with a Jovian-mass close-in planet. We analyzed these data with the aim to perform a detailed line-based emission measure analysis and derive the abundances of individual elements in the corona with two different methods applied independently. We compared the coronal abundances of τ Bootis with published photospheric abundances based on high-resolution optical spectra and with those of other late-type stars with different magnetic activity levels, including the Sun. Results. We find that the two methods provide consistent results within the statistical uncertainties for both the emission measure distribution of the hot plasma and for the coronal abundances, with discrepancies at the 2σ level limited to the amount of plasma at temperatures of 3-4 MK and to the O and Ni abundances. In both cases, the elements for which both coronal and photospheric measurements are available (C, N, O, Si, Fe, and Ni) result systematically less abundant in the corona by a factor 3 or more, with the exception of the coronal Ni abundance which is similar to the photospheric value. Comparison with other late-type stars of similar activity level shows that these coronal/photospheric abundance ratios are peculiar to τ Bootis and possibly related to the characteristic over-metallicity of this planet-hosting star.

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Section: Photospheric Abundancesmentioning

confidence: 57%

Photospheric and coronal abundances in solar-type stars: the peculiar case ofτ Bootis

Maggio

Sanz-Forcada

2011

A&A

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“…Luck & Heiter's (2007) abundance results for field giants are generally confirmed by Takeda et al (2008) for other large sample of field giants. Indeed, Luck & Heiter's (2007) [Mn/Fe] abundance ratios for red giants are 0.1 dex lower than their sample of field dwarfs (Luck & Heiter 2006). Both Luck & Heiter's (2007) and Takeda et al (2008) have employed similar abundance analysis based on the EW measurement of a large set of lines.…”

Section: Resultsmentioning

confidence: 99%

Comprehensive abundance analysis of red giants in the open clusters NGC 1342, 1662, 1912, 2354 and 2447

Reddy

Giridhar

Lambert

2015

Monthly Notices of the Royal Astronomical Society

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We have analyzed high-resolution echelle spectra of red giant members for seven open clusters in the Galactic anticentre direction to explore their chemical compositions. Cluster membership has been confirmed by radial velocity. The spread in temperatures and gravities being very small among the red giants, nearly the same stellar lines were employed for all stars thereby reducing the abundance errors: the errors of the average abundance for a cluster were generally in the 0.02 to 0.05 dex range. Our present sample covers Galactocentric distances of 8.3 to 11.3 kpc and an age range of 0.2 to 4.3 Gyr. A careful comparison of our results for the cluster NGC 2682 (M 67) to other high-resolution abundance studies in the literature shows general good agreement for almost all elements in common.

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“…M06 is Meléndez et al (2006), V05 is Valenti & Fischer (2005), S08 is Sousa et al (2008), B07 Barnes (2007), LH06 Luck & Heiter (2006), PM08 Porto de Mello et al (2008), T07 and T09 are Takeda et al (2007 and Takeda & Tajitsu (2009), respectively, G00 is Gaidos et al (2000) and MR07 is Meléndez & Ramírez (2007). S05 is Saffe et al (2005), G09 is Guinan &Engle (2009), andM08 Mamajek &Hillenbrand (2008).…”

Section: Discussionmentioning

confidence: 98%

“…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: 97%

Lithium depletion in solar-like stars: no planet connection

Baumann

Ramírez

Meléndez³

et al. 2010

A&A

165

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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Dwarfs in the Local Region

Cited by 137 publications

References 32 publications

Photospheric and coronal abundances in solar-type stars: the peculiar case ofτ Bootis

Photospheric and coronal abundances in solar-type stars: the peculiar case ofτ Bootis

Comprehensive abundance analysis of red giants in the open clusters NGC 1342, 1662, 1912, 2354 and 2447

Lithium depletion in solar-like stars: no planet connection

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