The discovery of Ni v in the photospheres of the hot DA white dwarfs RE 2214-492 and G191-B2B

J. B. Holberg, Ivan - Hubeny, M. A. Barstow, T. Lanz, E. M. Sion, R. W. Tweedy

Research output: Contribution to journalArticle

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Abstract

We have co-added six recently obtained IUE echelle spectra of the hot DA white dwarf RE 2214-492 and 10 existing archive spectra of the well-known hot DA, G191-B2B. We find that both stars contain numerous weak features due to Ni V. Nickel is thus the second iron-group element to be found in the spectra of the very hottest DA white dwarfs. In addition to Ni V, we also observe Al III in both stars and present evidence for the possible presence of Ni IV and Fe IV in RE 2214-492. The presence of Ni and Al, together with previously reported elements, will contribute significantly to both the EUV opacity and to the apparent complexity of the UV spectra of these stars. Using NLTE model atmospheres we estimate the Ni abundances in RE 2214-492 and G191-B2B to be log [Ni/H] = -5.5 ± 0.3 and -6.0 ± 0.3, respectively.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume425
Issue number2 PART 2
StatePublished - Apr 20 1994
Externally publishedYes

Fingerprint

photosphere
stars
IUE
opacity
nickel
iron
atmospheres
atmosphere
estimates

Keywords

  • 492, G191-B2B
  • Stars: abundances
  • Stars: individual: RE 2214
  • Ultraviolet: stars
  • White dwarfs

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Holberg, J. B., Hubeny, I. ., Barstow, M. A., Lanz, T., Sion, E. M., & Tweedy, R. W. (1994). The discovery of Ni v in the photospheres of the hot DA white dwarfs RE 2214-492 and G191-B2B. Astrophysical Journal, 425(2 PART 2).

The discovery of Ni v in the photospheres of the hot DA white dwarfs RE 2214-492 and G191-B2B. / Holberg, J. B.; Hubeny, Ivan -; Barstow, M. A.; Lanz, T.; Sion, E. M.; Tweedy, R. W.

In: Astrophysical Journal, Vol. 425, No. 2 PART 2, 20.04.1994.

Research output: Contribution to journalArticle

Holberg, JB, Hubeny, I, Barstow, MA, Lanz, T, Sion, EM & Tweedy, RW 1994, 'The discovery of Ni v in the photospheres of the hot DA white dwarfs RE 2214-492 and G191-B2B', Astrophysical Journal, vol. 425, no. 2 PART 2.
Holberg, J. B. ; Hubeny, Ivan - ; Barstow, M. A. ; Lanz, T. ; Sion, E. M. ; Tweedy, R. W. / The discovery of Ni v in the photospheres of the hot DA white dwarfs RE 2214-492 and G191-B2B. In: Astrophysical Journal. 1994 ; Vol. 425, No. 2 PART 2.
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AU - Holberg, J. B.

AU - Hubeny, Ivan -

AU - Barstow, M. A.

AU - Lanz, T.

AU - Sion, E. M.

AU - Tweedy, R. W.

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N2 - We have co-added six recently obtained IUE echelle spectra of the hot DA white dwarf RE 2214-492 and 10 existing archive spectra of the well-known hot DA, G191-B2B. We find that both stars contain numerous weak features due to Ni V. Nickel is thus the second iron-group element to be found in the spectra of the very hottest DA white dwarfs. In addition to Ni V, we also observe Al III in both stars and present evidence for the possible presence of Ni IV and Fe IV in RE 2214-492. The presence of Ni and Al, together with previously reported elements, will contribute significantly to both the EUV opacity and to the apparent complexity of the UV spectra of these stars. Using NLTE model atmospheres we estimate the Ni abundances in RE 2214-492 and G191-B2B to be log [Ni/H] = -5.5 ± 0.3 and -6.0 ± 0.3, respectively.

AB - We have co-added six recently obtained IUE echelle spectra of the hot DA white dwarf RE 2214-492 and 10 existing archive spectra of the well-known hot DA, G191-B2B. We find that both stars contain numerous weak features due to Ni V. Nickel is thus the second iron-group element to be found in the spectra of the very hottest DA white dwarfs. In addition to Ni V, we also observe Al III in both stars and present evidence for the possible presence of Ni IV and Fe IV in RE 2214-492. The presence of Ni and Al, together with previously reported elements, will contribute significantly to both the EUV opacity and to the apparent complexity of the UV spectra of these stars. Using NLTE model atmospheres we estimate the Ni abundances in RE 2214-492 and G191-B2B to be log [Ni/H] = -5.5 ± 0.3 and -6.0 ± 0.3, respectively.

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