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Wehrsě, R.; Rosenau, Philipp; Survernev, Andrei; Liebert, James; Leinert, Christoph

doi:10.1023/a:1001143727374

Cited by 13 publications

(28 citation statements)

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“…The broadest lines show strongly asymmetric profiles, which were in the case of Mg i 5169/5174/5185 originally identified as due to quasistatic broadening by Wehrse & Liebert (1980) in their study of SDSS1330+3029 (= G165-7). The same conclusion was reached by Kawka et al (2004) for SDSS1535+1247; both of these stars are in our present sample.…”

Section: Line Identification and Broadeningmentioning

confidence: 91%

“…SDSS1535+1247: this is a known white dwarf (WD 1532+129, G137-24), which was classified as DZ by Kawka et al (2004). Because the spectrum is similar to that of G165-7, they adopted the model of Wehrse & Liebert (1980) for that star with T eff = 7500 K and found metal abundances of ≈1/100 solar. They note, however, that a fit to the V JH photometry results in T eff = 6000 ± 400 K. The u − g and g − r colors are similar to SDSS1330+3029, yet the slope of the spectra is quite different.…”

Section: Notes For Individual Objectsmentioning

confidence: 99%

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Cool DZ white dwarfs in the SDSS

Koester

Girven²,

Gänsicke³

et al. 2011

A&A

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Aims. We report the identification of 26 cool DZ white dwarfs that lie across and below the main sequence in the Sloan Digital Sky Survey (SDSS) (u − g) vs. (g − r) two-color diagram; 21 of these stars are new discoveries. Methods. The sample was identified by visual inspection of all spectra of objects that fall below the main sequence in the two-color diagram, as well as by an automated search for characteristic spectral features over a large area in color space that included the main sequence. The spectra and photometry provided by the SDSS project are interpreted with model atmospheres, including all relevant metals. Effective temperatures and element abundances are determined, while the surface gravity has to be assumed and was fixed at the canonical value of logg = 8. Results. These stars represent the extension of the well-known DZ sequence towards cooler temperatures and fill the gap around T eff = 6500 K present in a previous study. The metal abundances are similar to those in the hotter DZ, but the lowest abundances are missing, probably because of our selection procedures. The interpretation is complicated in terms of the accretion/diffusion scenario, because we do not know if accretion is still occurring or has ended long ago. Independent of that uncertainty, the masses of the metals currently present in the convection zones -and thus an absolute lower limit of the total accreted masses -of these stars are similar to the largest asteroids in our solar system.

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Section: Line Identification and Broadeningmentioning

confidence: 91%

Section: Notes For Individual Objectsmentioning

confidence: 99%

Cool DZ white dwarfs in the SDSS

Koester

Girven²,

Gänsicke³

et al. 2011

A&A

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“…b Peculiar DQ with extremely strong C 2 bands (Carollo et al 2002(Carollo et al , 2003. c Heavily blanketed DZ (G 165-7) (Wehrse & Liebert 1980). d Unresolved binary (DC + magnetic DA) modeled by Bergeron et al (1997).…”

Section: Discussionmentioning

confidence: 99%

“…The right panel shows the spectrum of GSC2U J133059.8+302955 (G 165-7) which is a peculiar DZ with an estimated temperature of 7500 K (Wehrse & Liebert 1980). 5 The spectra of the two WDs GSC2U J124212.6+295801 and GSC2U J222233.1+122140 have a reduced wavelength coverage as they were observed at the TNG with a different Grism (LR-R).…”

Section: The Gsc2 Sample Of Wdsmentioning

confidence: 99%

The GSC-II-based survey of ancient cool white dwarfs

Carollo¹,

Bucciarelli²,

Hodgkin

et al. 2006

A&A

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The GSC-II white dwarf survey was designed to identify faint and high proper motion objects, which we used to define a new and independent sample of cool white dwarfs. With this survey we aim to derive new constraints on the halo white dwarf space density. Also, these data can provide information on the age of thick disk and halo through the analysis of the luminosity function. On the basis of astrometric and photometric parameters, we selected candidates with µ > ∼ 0.28 yr −1 and R F > ∼ 16 in an area of 1150 square degrees. Then, we separated white dwarfs from late type dwarfs and subdwarfs by means of the reduced proper motion diagram. Finally, spectroscopic follow-up observations were carried out to confirm the white dwarf nature of the selected candidates. We found 41 white dwarfs of which 24 are new discoveries. Here we present the full sample and for each object provide positions, absolute proper motions, photometry, and spectroscopy.

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“…Both gϪr and especially bϪv are substantially redder than the pure-He models predict. Likewise, LHS 2534 is cooler than the heavily blanketed DZ star G165-7, for which Wehrse & Liebert (1980) estimated 7500 K and the vϪi color (Greenstein 1984) suggests 7100 K. Perhaps the most similar of the well-known DZ stars is van Maanen 2, at gϪr p ϩ0.26 and vϪ . Bergeron, Ruiz, & Leggett (1997) i p ϩ0.13 estimate 6770 K from fitting a multicolor energy distribution of this star.…”

Section: The Lhs 2534 Spectrummentioning

confidence: 93%

Discovery of a Magnetic DZ White Dwarf with Zeeman-Split Lines of Heavy Elements

Reid

Liebert

Schmidt

2001

The Astrophysical Journal

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A spectroscopic survey of unstudied Luyten half-second proper-motion stars has resulted in the discovery of an unusual new magnetic white dwarf. LHS 2534 proves to be the first magnetic DZ, showing Zeeman-split Na i and Mg i components, as well as Ca i and Ca ii lines for which Zeeman components are blended. The Na i splittings result in a mean surface field strength estimate of 1.92 MG. Apart from the magnetic field, LHS 2534 is one of the most heavily blanketed and coolest DZ white dwarfs at K. T ∼ 6000 eff Subject headings: stars: magnetic fields -white dwarfs

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Cited by 13 publications

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Cool DZ white dwarfs in the SDSS

Cool DZ white dwarfs in the SDSS

The GSC-II-based survey of ancient cool white dwarfs

Discovery of a Magnetic DZ White Dwarf with Zeeman-Split Lines of Heavy Elements

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