Ultraviolet and X-ray detection of the 56 Pegasi system /K0 IIp + WD/ - Evidence for accretion of a cool stellar wind onto a white dwarf

Schindler, M.; Linsky, Jeffrey L.; Helfand, D. J.; Stencel, R. E.; Basri, Gibor

doi:10.1086/160501

Cited by 22 publications

(13 citation statements)

References 7 publications

(10 reference statements)

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“…References. (1) Fekel et al (1993); (2) Landsman et al (1993); (3) Vennes et al (1998) (4) Burleigh et al (1997); (5) Merle et al (2014); (6) Jorissen et al (1996); (7) ; (8) Stefanik et al (2011); (9) Dominy & Lambert (1983); (10) Griffin & Keenan (1992); (11) Schindler et al (1982); (12) Griffin (2006); (13) Frankowski & Jorissen (2006); (14) Böhm-Vitense (1980); (15) Jorissen et al (1998); (16) Jorissen et al (1995); (17) Fekel & Simon (1985).…”

Section: Introductionmentioning

confidence: 99%

To Ba or not to Ba: Enrichment ins-process elements in binary systems with WD companions of various masses

Merle

Jorissen

Eck

et al. 2016

A&A

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Context. The enrichment in s-process elements of barium stars is known to be due to pollution by mass transfer from a companion formerly on the thermally pulsing asymptotic giant branch (AGB), now a carbon-oxygen white-dwarf (WD). Aims. We are investigating the relationship between the s-process enrichment in the barium star and the mass of its WD companion. It is expected that helium WDs, which have masses lower than about 0.5 M and never reached the AGB phase, should not pollute their giant companion with s-process elements. Therefore the companion should never turn into a barium star. Methods. Spectra with a resolution of R ∼ 86 000 were obtained with the HERMES spectrograph on the 1.2 m Mercator telescope for a sample of 11 binary systems involving WD companions of various masses. We used standard 1D local thermodynamical equilibrium MARCS model atmospheres coupled with the Turbospectrum radiative-transfer code that is embedded in the BACCHUS pipeline to derive the atmospheric parameters through equivalent widths of Fe i and Fe ii lines. Least-squares minimization between the observed and synthetic line shape was used to derive the detailed chemical abundances of CNO and s-process elements.Results. The abundances of s-process elements for the entire sample of 11 binary stars were derived homogeneously. The sample encompasses all levels of overabundances: from solar [s/Fe] = 0 to 1.5 dex in the two binary systems with S-star primaries (for which dedicated MARCS model atmospheres were used). The primary components of binary systems with a WD more massive than 0.5 M are enriched in s-process elements. We also found a trend of increasing [s/Fe] with [C/Fe] or [(C+N)/Fe]. Conclusions. Our results confirm the expectation that binary systems with WD companions less massive than 0.5 M do not host barium stars.

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Section: Introductionmentioning

confidence: 99%

To Ba or not to Ba: Enrichment ins-process elements in binary systems with WD companions of various masses

Merle

Jorissen

Eck

et al. 2016

A&A

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“…For example, the white dwarf companion to HD27483 (Böhm-Vitense 1993) was discovered as part of an IUE study of Hyades F stars by Böhm-Vitense (1995). Others detected in a similar fashion include ζ Cap (Böhm-Vitense 1980), 56 Peg (Schindler et al 1982) and 4 o 1 Ori (Johnson & Ake 1986).…”

Section: Introductionmentioning

confidence: 99%

A search for hidden white dwarfs in the ROSAT extreme ultraviolet survey

Burleigh¹,

Barstow²,

Fleming³

1997

Monthly Notices of the Royal Astronomical Society

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The ROSAT WFC survey has provided us with evidence for the existence of a previously unidentified sample of hot white dwarfs (WD) in non-interacting binary systems, through the detection of EUV and soft X-ray emission. These stars are hidden at optical wavelengths due to their close proximity to much more luminous main sequence (MS) companions (spectral type K or earlier). However, for companions of spectral type ∼A5 or later the white dwarfs are easily visible at far-UV wavelengths, and can be identified in spectra taken by IUE. Eleven white dwarf binary systems have previously been found in this way from ROSAT, EUVE and IUE observations (e.g. Barstow et al. 1994). In this paper we report the discovery of three more such systems through our programmes in recent episodes of IUE. The new binaries are HD2133, RE J0357+283 (whose existence was predicted by Jeffries, Burleigh and Robb 1996), and BD+27 • 1888. In addition, we have independently identified a fourth new WD+MS binary, RE J1027+322, which has also been reported in the literature by Genova et al. (1995), bringing the total number of such systems discovered as a result of the EUV surveys to fifteen. We also discuss here six stars which were observed as part of the programme, but where no white dwarf companion was found. Four of these are coronally active. Finally, we present an analysis of the WD+K0IV binary HD18131 (Vennes et al. 1995), which includes the ROSAT PSPC X-ray data.

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“…(2) Wilson-Bappu magnitudes derived from Ca K and Mg k disagree strongly, by some 4 mag; (3) the spectrum contains "hot" lines due to C iv and N v, despite its location far above the Linsky-Haisch temperature boundary. This peculiar object is discussed in detail by Schindler et al (1981).…”

Section: Variations In the Spectramentioning

confidence: 91%

Magnesium emission variability among late-type giant stars

Mullan¹,

Stencel²

1982

ApJ

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We have investigated the variability of the emission cores in the h and k Unes of Mg n in a sample of 21 late-type giants. We have used high resolution line profiles obtained by IUE \o determine not only the total emission intensity, but also the ratio of the intensities of the shortward and longward components of the doubly-reversed emission. We argue that variations in the total emission intensity are indicative of variations in chromospheric heating, while variations in the ratio can be interpreted in terms of variations in structures in the corona and outer atmosphere.

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Ultraviolet and X-ray detection of the 56 Pegasi system /K0 IIp + WD/ - Evidence for accretion of a cool stellar wind onto a white dwarf

Cited by 22 publications

References 7 publications

To Ba or not to Ba: Enrichment ins-process elements in binary systems with WD companions of various masses

To Ba or not to Ba: Enrichment ins-process elements in binary systems with WD companions of various masses

A search for hidden white dwarfs in the ROSAT extreme ultraviolet survey

Magnesium emission variability among late-type giant stars

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