J/AcA/74/43 Nearby B-type stars phosphorus abundances (Takeda, 2024)
Phosphorus Abundances of B-Type Stars in the Solar Neighborhood.
Takeda Y.
<Acta Astron. 74, 43 (2024)>
=2024AcA....74...43T 2024AcA....74...43T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Abundances ; Optical
Keywords: solar neighborhood - stars: abundances - stars: chemically peculiar -
stars: early-type
Abstract:
Phosphorus abundances of ∼80 apparently bright sharp-lined
early-to-late B-type stars on the upper main sequence are determined
by applying the non-LTE analysis to the PII line at 6043.084Å, with
the aim of getting information on the P abundance of the galactic gas
(from which these young stars were formed) in comparison to the
reference solar abundance (A☉∼5.45). These sample stars turned
out to be divided into two distinct groups with respect to their P
abundances. Chemically peculiar late B-type stars of HgMn group show
considerable overabundances of P (supersolar by ∼0.5-1.5dex), the
extent of which progressively increases with Teff. In contrast, the P
abundances of normal B-type stars are comparatively homogeneous,
though a notable difference is observed between the LTE and non-LTE
cases. Although their LTE abundances are near-solar, a slight gradual
trend with Teff is observed. However, after applying the negative
non-LTE corrections (amounting ∼0.1-0.5dex), this Teff -dependence is
successfully removed, but the resulting non-LTE abundances (their mean
is ∼5.20 ) are appreciably underabundant relative to the Sun by
∼0.2-0.3dex. The cause of this systematic discrepancy, contradicting
the galactic chemical evolution, is yet to be investigated.
Description:
The observational materials used in this study are the high-dispersion
(R∼70000) and high-S/N (∼200-700) spectra obtained by HIgh Dispersion
Echelle Spectrograph (HIDES) placed at the coude focus of the 188cm
reflector at Okayama Astrophysical Observatory,
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 79 85 Program stars and the results of the analysis
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Samp [AB] Sample (1)
3- 8 I6 --- HD HD number
10- 13 I4 --- HR HR number
15- 26 A12 --- OName Star name
28- 39 A12 --- SpType Spectral type
41- 45 I5 K Teff Effective temperature (2)
47- 50 F4.2 [cm/s2] logg Surface gravity (2)
52- 53 I2 km/s vesini Projected rotational velocity (3)
55- 59 F5.1 0.1pm W6043 ?=- Equivalent width of PII 6043 line
61- 64 F4.2 --- AL ?=- P abundance in LTE
66- 70 F5.2 --- DELTA ?=- Non-LTE correction
72- 75 F4.2 --- AN ?=- P abundance in non-LTE
77- 79 I3 --- S/N Signal-to-noise ratio (4)
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Note (1): Samples as follows:
A = 2006 October observations (early-to-late B-type stars)
B = 2012 May observations (late B-type stars)
Note (2): Determined from color indices of Stroemgren uvbyβ photometry
(cf. Section 3).
Note (3): Determined from the fitting analysis around ∼6150-6160Å region
(cf. y Takeda et al. (2010PASJ...62.1239T 2010PASJ...62.1239T, Paper I) and
Takeda et al. (2014PASJ...66...23T 2014PASJ...66...23T, Paper II).
Note (4): Mean of the results measured from five segments in the neighborhood
of the PII 6043 line.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 27-Aug-2025