Spectral investigation of a group of new cataclysmic variables from the First Byurakan Survey with the 6-m telescope

Kopylov, I. M.; Lipovetskii, V. A.; Somov, N. N.; Somova, T. A.; Stepanyan, Dzh A.

doi:10.1007/bf01004065

Cited by 9 publications

(11 citation statements)

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“…He I A4471 is also weakly present, so I infer that the proper spectral type is sdB-O. Kopylov et al (1988) show an absorption spectrum. filled in low-dispersion spectra: note the difference in Ho; line profiles between the spectra in Appendix B.…”

Section: Pg 0947+462mentioning

confidence: 93%

The Cataclysmic Variables from the Palomar-Green Survey

Ringwald¹

1993

PASP

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This thesis explores the cataclysmic variables (CVs) found by the Palomar-Green (PG) survey. This is the first compilation of a statistically complete sample of CV s found by ultraviolet color excess, and not outburst behavior. Blue and red follow-up spectrophotometry suggests that 22 of 68 objects classified originally as CV s are hot subdwarfs.Cool companions may be mimicking CVs' flat energy distributions, although the possibility remains that some are face-on CV s. Spectra taken with the International Ultraviolet Explorer satellite prove useful for distinguishing difficult cases.With the CV sample defined, the orbital periods for eleven systems are investigated with radial velocity studies. At 16th magnitude, CV number counts increase by 2.3 mag-I, although this may level off. The luminosity function is examined for the first time, and a trend toward higher space density at low luminosity is suspected. Outburst properties are compiled, and low-luminosity dwarf nove inflate the total space density to 6 x 10-6 pc-3 . I I describe all the PG CV s and candidate objects, and show spectra for most. This sample should be useful for population studies, such as measuring the space density with trigonometric parallaxes, or finding the fraction of eclipsing CV s.A new class of nova-likes, the SW Sextans stars, is characterized by absorption events of the emission lines at spectroscopic phase 0.5, accompanied by large phase lags between the lightcurves and the radial velocity curves and strong high-excitation emission.There are at least six such CVs in this sample of 33, so this mysterious behavior must be common and not peculiar, as previously thought. Five of these six objects eclipse._Serendipitous results for individual CVs include finding low-frequency quasi-periodic variations in the radial velocity curve of the dwarf nova BZ Ursa Majoris. While erratic from epoch to epoch, these are too coherent to be pure noise. Another dwarf nova, HX Pegasi, is caught with time-resolved spectrophotometry on the rise to outburst. This is the second-ever such observation, and the first with red spectra. HX Pegasi is also confirmed as having a novel subdwarf-K red star. II

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Section: Pg 0947+462mentioning

confidence: 93%

The Cataclysmic Variables from the Palomar-Green Survey

Ringwald¹

1993

PASP

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“…It has been identified in the First Byurakan Survey, a spectroscopic galaxy survey, as a CV because of its noticeable Balmer emission lines. Stepanian (1982) reported brightness variations in the range V ≈ 15−17.5 and suggested that DW Cnc is a dwarf nova, a classification later supported by Kopylov et al (1988).…”

Section: Introductionmentioning

confidence: 99%

DW Cancri: a magnetic VY Scl star with an orbital period of 86 min

Rodríguez‐Gil

Gänsicke

Araujo-Betancor

et al. 2004

Monthly Notices of the Royal Astronomical Society

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We present the first time‐resolved spectroscopic study of the cataclysmic variable DW Cancri. We have determined an orbital period of 86.10 ± 0.05 min, which places the system very close to the observed minimum period of hydrogen‐rich cataclysmic variables. This invalidates previous speculations of DW Cnc being either a permanent superhumper below the period minimum or a nova‐like variable with an orbital period longer than 3 h showing quasi‐periodic oscillations. The Balmer and He i lines have double‐peaked profiles and exhibit an intense S‐wave component moving with the orbital period. Remarkably, the Balmer and He i radial velocity curves are modulated at two periods: 86.10 ± 0.05 (orbital) and 38.58 ± 0.02 min. The same short period is found in the equivalent width variations of the single‐peaked He ii 4686 line. We also present time‐resolved photometry of the system which shows a highly coherent variation at 38.51 min, consistent with the short spectroscopic period. The large number of similarities with the short‐period intermediate polar V1025 Cen lead us to suggest that DW Cnc is another intermediate polar below the period gap, and we tentatively identify the photometric and spectroscopic 38‐min signals with the white dwarf spin period. DW Cnc has never been observed to undergo an outburst, but it occasionally exhibits low states ∼2 mag fainter than its typical brightness level of V≃ 14.5, resembling the behaviour of the high mass‐transfer VY Scl stars.

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“…It was suspected to be a U Gem type cataclysmic variable (CV; Downes et al 2001), but has not been confirmed (Kopylov et al 1988). Its strong IR excess (V À K ¼ 4 mag; Hoard et al 2002) is typical of FS CMa stars and should be due to dust, since the optical reddening is weak (B À V ¼ 0:1 mag).…”

Section: Fbs 0022à021mentioning

confidence: 99%

Toward Understanding the B[e] Phenomenon. II. New Galactic FS CMa Stars

Мирошниченко

Manset

Kusakin

et al. 2007

ApJ

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FS CMa stars form a group of objects with the B[e] phenomenon that were previously known as unclassified B[e] stars or B[e] stars with warm dust (B[e]WD) until recently. They exhibit strong emission-line spectra and strong IR excesses, most likely due to recently formed circumstellar dust. These properties have been suggested to be due to ongoing or recent rapid mass exchange in binary systems with hot primaries and various types of secondaries. The first paper of this series reported an analysis of the available information about previously known Galactic objects with the B[e] phenomenon, the initial selection of the FS CMa group objects, and a qualitative explanation of their properties. This paper reports the results of our new search for more FS CMa objects in the IRAS Point Source Catalog. We present new photometric criteria for identifying FS CMa stars as well as the first results of our observations of nine new FS CMa group members. With this addition, the FS CMa group has now 40 members, becoming the largest among the dust-forming hot star groups. We also present nine objects with no evidence for the B[e] phenomenon, but with newly discovered spectral line emission and/or strong IR excesses.

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Spectral investigation of a group of new cataclysmic variables from the First Byurakan Survey with the 6-m telescope

Cited by 9 publications

References 1 publication

The Cataclysmic Variables from the Palomar-Green Survey

The Cataclysmic Variables from the Palomar-Green Survey

DW Cancri: a magnetic VY Scl star with an orbital period of 86 min

Toward Understanding the B[e] Phenomenon. II. New Galactic FS CMa Stars

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