Light element non-LTE abundances of<i>λ</i>Bootis stars

Kamp, I.; Iliev, I. Kh.; Paunzen, E.; Pintado, O. I.; Solano, E.; Barzova, I. S.

doi:10.1051/0004-6361:20010886

Cited by 33 publications

(61 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Kamp et al (2001) find nitrogen quite variable among λ Boo stars, and subject to NLTE. For example, the LTE abundance excess of N for HD 75654 was +0.65 dex.…”

Section: Nitrogenmentioning

confidence: 81%

Abundances in the Herbig Ae star HD 101412

Cowley

Hubrig

González

et al. 2010

A&A

View full text Add to dashboard Cite

Context. Recent attention has been directed to abundance variations among very young stars. Aims. We perform a detailed abundance study of the Herbig Ae star HD 101412, taking advantage of its unusually sharp spectral lines. Methods. High-resolution spectra are measured for accurate wavelengths and equivalent widths. Balmer-line fits and ionization equlibria give a relation between T eff , and log(g). Abundance anomalies and uncertain reddening preclude the use of spectral type or photometry to fix T eff . Excitation temperatures are used to break the degeneracy between T eff and log(g). Results. Strong lines are subject to an anomalous saturation that cannot be removed by assuming a low microturbulence. By restricting the analysis to weak (≤20 mÅ) lines, we find consistent results for neutral and ionized species, based on a model with T eff = 8300 K, and log(g) = 3.8. The photosphere is depleted in the most refractory elements, while volatiles are normal or, in the case of nitrogen, overabundant with respect to the sun. The anomalies are unlike those of Ap or Am stars. Conclusions. We suggest the anomalous saturation of strong lines arises from heating of the upper atmospheric layers by infalling material from a disk. The overall abundance pattern may be related to those found for the λ Boo stars, though the depletions of the refractory elements are milder, more like those of Vega. However, the intermediate volatile zinc is depleted, precluding a straightforward interpretation of the abundance pattern in terms of gas-grain separation.

show abstract

“…Kamp et al (2001) find nitrogen quite variable among λ Boo stars, and subject to NLTE. For example, the LTE abundance excess of N for HD 75654 was +0.65 dex.…”

Section: Nitrogenmentioning

confidence: 81%

Abundances in the Herbig Ae star HD 101412

Cowley

Hubrig

González

et al. 2010

A&A

View full text Add to dashboard Cite

show abstract

“…Asterisks mark cases where AW and the present work agree on possibly significant departures from solar abundances. NLTE effects could also be responsible for some non-solar abundances (Kamp et al 2001). …”

Section: Abundancesmentioning

confidence: 99%

The absorption and emission spectrum of the magnetic Herbig Ae star HD 190073

Cowley¹,

Hubrig²

2012

Astron Nachr

View full text Add to dashboard Cite

We determine abundances from the absorption spectrum of the magnetic Herbig Ae star HD 190073 (V1295 Aql). The observations are primarily from HARPS spectra obtained at a single epoch. We accept arguments that the presence of numerous emission lines does not vitiate a classical abundance analysis, though it likely reduces the achievable accuracy. Most abundances are closely solar, but several elements show departures of a factor of two to three, as an earlier study has also shown. We present quantitative measurements of more than 60 emission lines, peak intensities, equivalent widths, and FWHM's. The latter range from over 200 km s −1 (Hα, He D3) down to 10-20 km s −1 (forbidden lines

show abstract

“…In spite of this duplicity detection, the abundances of O, N, and S have been determined by these authors and by Kamp et al (2001) in LTE and NLTE treating the star as single.…”

Section: Hd 149303: Wrong Binary Detection?mentioning

confidence: 99%

$\mathsf{\lambda}$ Bootis stars with composite spectra

Faraggiana

Bonifacio

Caffau

et al. 2004

A&A

View full text Add to dashboard Cite

Abstract.We examine the large sample of λ Boo candidates collected in Table 1 of Gerbaldi et al. (2003) to see how many of them show composite spectra. Of the 132 λ Boo candidates we identify 22 which definitely show composite spectra and 15 more for which there are good reasons to suspect a composite spectrum. The percentage of λ Boo candidates with composite spectra is therefore >17% and possibly considerably higher. For such stars the λ Boo classification should be reconsidered taking into account the fact that their spectra are composite. We argue that some of the underabundances reported in the literature may simply be the result of the failure to consider the composite nature of the spectra. This leads to the legitimate suspicion that some, if not all, the λ Boo candidates are not chemically peculiar at all. A thorough analysis of even a single one of the λ Boo candidates with composite spectra, in which the composite nature of the spectrum is duly considered, which would demonstrate that the chemical peculiarities persist, would clear the doubt we presently have that the stars with composite spectra may not be λ Boo stars at all.

show abstract

Light element non-LTE abundances ofλBootis stars

Cited by 33 publications

References 20 publications

Abundances in the Herbig Ae star HD 101412

Abundances in the Herbig Ae star HD 101412

The absorption and emission spectrum of the magnetic Herbig Ae star HD 190073

$\mathsf{\lambda}$ Bootis stars with composite spectra

Contact Info

Product

Resources

About