J/ApJ/899/166 ASTRAL: abundance analysis of HR 465 (Nielsen+, 2020)
The Advanced Spectral Library (ASTRAL): Abundance Analysis of the Chemically
Peculiar Star HR 465.
Nielsen K.E., Carpenter K.G., Kober G.V., Wahlgren G.M.
<Astrophys. J., 899, 166 (2020)>
=2020ApJ...899..166N 2020ApJ...899..166N
ADC_Keywords: Stars, Bp; Spectra, ultraviolet; Abundances
Keywords: Chemically peculiar stars ; Stellar abundances ; Bp stars ;
High resolution spectroscopy ; Astronomy data modeling
Abstract:
This paper presents the results of the spectrum analysis of the B-type
magnetic chemically peculiar star HR465. HR465 shows unusual abundance
patterns that vary with a period of 21.5yr. Our observations are
recorded at ph=0.45, 0.68, and 0.85 of the spectroscopic period, where
ph=0 represents the phase of maximum flux in the photometric y-band.
Synthetic spectra, computed using an LTE atmosphere model, are fit to
high-resolution ultraviolet Hubble Space Telescope (ph=0.45) spectra
obtained as part of the Advanced Spectral Library Project: Hot Stars
program. The ultraviolet data are supplemented by high-resolution
optical spectra (ph=0.68 and 0.85) recorded at the Nordic Optical
Telescope with the SOFIN spectrograph. The optical data are used as a
complement to the high line-density ultraviolet spectrum to derive
accurate abundances for elements without spectral lines in the
ultraviolet and to improve the abundance phase coverage for many
atoms/ions. This analysis presents abundance results for more than 70
atoms/ions and confirms parts of the abundance characteristics
previously reported where elements with high mass numbers show
significant abundance enhancements compared with solar values while
some of the lighter elements show abundance deficiencies. In addition,
our measured abundances are consistent with the periodic variability
for chromium and rare-earth elements. Our results are compared with
earlier investigations of this peculiar object to constrain stellar
abundance and diffusion.
Description:
The ASTRAL: Hot Stars Treasury Program was designed to achieve the
ultimate combination of high spectral resolution and signal-to-noise
over the far- and near-ultraviolet spectrum. The spectrum of HR465
covers the wavelength interval between 1150 and 3047Å and is
composed of 21 coadded and merged individual recordings. The spectral
resolution shortward of 2334Å is R∼30000; however, for wavelengths
below 1600Å the spectrum is modeled with a lower value (R∼25000) to
achieve a better match to the observation. For wavelengths above
2350Å the spectral resolution is ∼117000.
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------
01 38 31.82 +45 23 59.0 HR 465 = V* GY And
---------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 48 631 Lines used in the HR465 abundance analysis
refs.dat 111 73 References used for table2
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See also:
J/ApJS/99/135 : Rotation and Spectral Peculiarities (Abt+ 1995)
J/A+AS/123/353 : Mean magnetic field modulus of Ap stars (Mathys, 1997)
J/A+A/394/151 : Multiplicity among chemically peculiar starsII (Carrier+,2002)
J/A+A/385/716 : N-like and O-like Breit-Pauli energy levels (Tachiev+, 2002)
J/A+A/601/A14 : Radial velocities of magnetic Ap stars (Mathys, 2017)
J/ApJ/869/157 : ASTRAL, reference spectra evolved M stars (Carpenter+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Species Species studied
8- 15 F8.3 0.1nm Wave [27.9/6678] Laboratory wavelength in Angstroms
17- 22 I6 /cm Elow [0/134041] Energy for the transition's lower level
24- 27 A4 [-] (X/H) Abundance (X/H)=log(NX)-log(NH)+12.0
29- 33 F5.2 [-] loggf [-4.37/1.13] Log oscillator strength*statistical
weight
35- 48 A14 --- Ref References on loggf
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Ref Reference code
16- 39 A24 --- Autor Main autor
41- 59 A19 --- BIB BIBcode
61- 74 A14 --- Cat. Catalog reference in Vizier
76-111 A36 --- Link Link for reference
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 25-Oct-2021