Discovery of a dwarf carbon star with a white dwarf companion and of a highly magnetic degenerate star

Liebert, James; Schmidt, Gary D.; Lesser, Michael P.; Stepanian, J. A.; Lipovetsky, V. A.; Chaffe, Frederic H.; Foltz, C. B.; Bergeron, P.

doi:10.1086/173685

Cited by 61 publications

(49 citation statements)

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“…g The companion of WD 1517+502 is a dwarf carbon star (Liebert et al 1994). h WD 1610+383 is barely resolved on the DSS images as a common proper motion pair with red and blue components at a separation of %4 00 .…”

Section: No 2 2003 2mass Data On White Dwarf Companionsmentioning

confidence: 99%

Cool Companions to White Dwarfs from the Two Micron All‐Sky Survey Second Incremental Data Release

Wachter

Hoard

Hansen

et al. 2003

ApJ

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We present near-infrared (IR) magnitudes for all white dwarfs (selected from the catalog of McCook & Sion) contained in the Two Micron All-Sky Survey second incremental data release (2MASS 2IDR). We show that the near-IR color-color diagram is an effective means of identifying candidate binary stars containing a WD and a low-mass, main-sequence star. The loci of single WDs and WD+red dwarf binaries occupy distinct regions of the near-IR color-color diagram. We recovered all known unresolved WD+red dwarf binaries located in the 2IDR sky coverage and also identified as many new candidate binaries (47 new candidates out of 95 total). Using observational near-IR data for WDs and M-L dwarfs, we have compared a sample of simulated WD+red dwarf binaries with our 2MASS data. The colors of the simulated binaries are dominated by the low-mass companion through the late M to early L spectral types. As the spectral type of the companion becomes progressively later, however, the colors of unresolved binaries become progressively bluer. Binaries containing the lowest mass companions will be difficult to distinguish from single WDs solely on the basis of their near-IR colors.

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Section: No 2 2003 2mass Data On White Dwarf Companionsmentioning

confidence: 99%

Cool Companions to White Dwarfs from the Two Micron All‐Sky Survey Second Incremental Data Release

Wachter

Hoard

Hansen

et al. 2003

ApJ

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“…In total, 171 objects were observed photometrically, 45 on the 60 cm KPNO Burrell Schmidt telescope and 138 (12 objects are in common with the Burrell Schmidt) on the 1.2 m telescope of the Whipple Observatory. CCD B, V , and B[V magnitudes of two peculiar objects (a DA]dC binary system [SBS 1517]502] and a DA magnetic star [SBS 1349]545 ; Liebert et al 1994]), the ELG SBS 1438]594, and 168 QSOs and Seyfert galaxies were obtained. Twelve objects were observed on both telescopes during the 1993 observations.…”

Section: Fig 2èspectra Of Stars Observed With the 6 M Telescopementioning

confidence: 99%

Spectroscopy and Photometry of Stellar Objects from the Second Byurakan Survey

Stepanian

Green

Foltz

et al. 2001

The Astronomical Journal

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The results of spectroscopic observations of 202 stellar objects, and photometric observations of 171, from the Second Byurakan Survey (SBS) are reported. The SBS sample has proved to be a rich source of newly identiÐed quasars, Seyfert-type galaxies, degenerate stars, and hot subdwarfs. In this subsample we have identiÐed 71 new QSOs ; one BL Lacertae object ; one Seyfert 1 galaxy ; one LINER ; one blue compact galaxy ; 31 white dwarfs (WDs), 25 of DA type and six of DB type ; 26 subdwarfs ; 11 horizontal-branch B-type, 11 normal/horizontal-branch, 18 G-type, and 11 F-type stars ; 10 objects with composite spectra ; two cataclysmic variables ; and six objects with continuous spectra. We present accurate positions, spectral classiÐcations, and magnitudes for all objects. The Ó. redshifts, equivalent widths, and spectra for QSOs and emission-line galaxies are given, as are some typical spectra for hot stars. The vast majority (63%) of stellar objects selected in the SBS turned out to be WDs (36%) and sdB subdwarfs (27%). Only D5%È7% of objects with B \ 16.4 and D13% with B D 17.0 were identiÐed as QSOs. In total, 470 QSOs and D500 hot stars were discovered in the course of the SBS. The lower limit on the surface density of bright QSOs in the redshift range 0.3 \ z \ 2.2 is no fewer than 0.06 deg~2 for B \ 17.0 and 0.13 deg~2 for B \ 17.5. The surface density of DA WDs is estimated to be 0.06 deg~2 for B \ 16.0 and 0.14 deg~2 for B \ 17.0.

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“…However, high proper motions and trigonometric parallax measurements (Dahn et al 1977) showed that the carbon star G 77-61 has the luminosity of a main-sequence dwarf. In recent years, more faint carbon stars have been shown to have measurable proper motion and dwarf star luminosities (Green et al 1991(Green et al , 1992Heber et al 1993;Warren et al 1993;Liebert et al 1994). …”

Section: Introductionmentioning

confidence: 99%