2007A&A...469..297A


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.05CEST07:13:14

2007A&A...469..297A - Astronomy and Astrophysics, volume 469, 297-305 (2007/7-1)

HS 1857+5144: a hot and young pre-cataclysmic variable.

AUNGWEROJWIT A., GAENSICKE B.T., RODRIGUEZ-GIL P., HAGEN H.-J., GIANNAKIS O., PAPADIMITRIOU C., ALLENDE PRIETO C. and ENGELS D.

Abstract (from CDS):

We report the discovery of a new white dwarf/M dwarf binary, HS1857+5144, identified in the Hamburg Quasar Survey (HQS). Time-resolved optical spectroscopy and photometry were carried out to determine the properties of this new cataclysmic variable progenitor (pre-CV). The light curves of HS1857+5144 display a sinusoidal variation with a period of Porb=383.52min and peak-to-peak amplitudes of 0.7mag and 1.1mag in the B-band and R-band, respectively. The large amplitude of the brightness variation results from a reflection effect on the heated inner hemisphere of the companion star, suggesting a very high temperature of the white dwarf. Our radial velocity study confirms the photometric period as the orbital period of the system. A model atmosphere fit to the spectrum of the white dwarf obtained at minimum light provides limits to its mass and temperature of Mwd≃0.6-1.0M and Twd≃70000-100000K, respectively. The detection of HeIIλ4686 absorption classifies the primary star of HS1857+5144 as a DAO white dwarf. Combining the results from our spectroscopy and photometry, we estimate the mass of the companion star and the binary inclination to be Msec≃0.15-0.30M and i≃45°-55°, respectively. We classify HS1857+5144 as one of the youngest pre-CV known to date. The cooling age of the white dwarf suggests that the present system has just emerged from a common envelope phase ∼105yr ago. HS1857+5144 will start mass transfer within or below the 2-3h period gap.

Abstract Copyright:

Journal keyword(s): stars: binaries: close - stars: individual: HS 1857+5144

CDS comments: paragr.2.1: HS 1136+6644 is a misprint for HS 1136+6646.

Simbad objects: 15

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Number of rows : 15

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 PN HFG 1 PN 03 03 47.0096103383 +64 54 35.516249865     14.56 13.99   ~ 96 0
2 PN K 1-2 PN 08 57 45.9618160284 -28 57 36.577010750           ~ 109 1
3 CD-48 6027 HS* 10 54 40.5600843998 -48 47 02.815812625 10.92 11.99 12.12 12.39   sdO 107 0
4 HS 1136+6646 WD* 11 39 05.7723617261 +66 30 17.767104710           DAO.6 39 0
5 V* BE UMa CV* 11 57 44.8280752290 +48 56 18.315294262     15.09     DO+M1/5e 118 0
6 EC 11575-1845 HS* 12 00 05.6457009978 -19 02 03.968468680   13.02 13.20 13.51   sdO+dMe 33 1
7 V* NN Ser No* 15 52 56.1202658103 +12 54 44.432043501     16.51     DAO1+M4 232 0
8 PN A66 46 PN 18 31 18.290 +26 56 12.86   14.88 15.07     O9k 154 0
9 USNO-A2.0 1350-10078272 * 18 58 25.4539243016 +51 48 01.496306188   16.1   14.5   ~ 1 0
10 USNO-A2.0 1350-10078502 * 18 58 26.4418820641 +51 47 44.762132722   14.6   13.5   ~ 1 0
11 USNO-A2.0 1350-10079362 * 18 58 29.8998020361 +51 48 57.646770158   17.8   16.4   ~ 1 0
12 HS 1857+5144 CV* 18 58 32.0881509107 +51 48 57.519212519   15.7   16.3   M5 13 0
13 USNO-A2.0 1350-10080469 * 18 58 34.2030315017 +51 47 32.137883885   14.7   13.2   ~ 1 0
14 PN A66 65 PN 19 46 34.2091755631 -23 08 12.970430769   15.93 15.77 16.00 15.65 Opk 122 0
15 HS 2333+3927 HS* 23 35 42.5026291966 +39 44 27.064897144     14.53     sdOB 35 0

    Equat.    Gal    SGal    Ecl

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2020.07.05-07:13:14

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