2008A&A...484..441S


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.24CEST02:44:47

2008A&A...484..441S - Astronomy and Astrophysics, volume 484, 441-450 (2008/6-3)

Post common envelope binaries from SDSS. II: Identification of 9 close binaries with VLT/FORS2.

SCHREIBER M.R., GAENSICKE B.T., SOUTHWORTH J., SCHWOPE A.D. and KOESTER D.

Abstract (from CDS):

Post common envelope binaries (PCEBs) consisting of a white dwarf and a main sequence star are ideal systems to use to calibrate current theories of angular momentum loss in close compact binary stars. The potential held by PCEBs for further development of close binary evolution could so far not be exploited due to the small number of known systems and the inhomogeneity of the sample. The Sloan Digital Sky Survey is changing this scene dramatically, as it is very efficient in identifying white dwarf/main sequence (WDMS) binaries, including both wide systems whose stellar components evolve like single stars and - more interesting in the context of close binary evolution - PCEBs. We pursue a large-scale follow-up survey to identify and characterise the PCEBs among the WDMS binaries that have been found with SDSS. We use a two-step strategy with the identification of PCEBs among WDMS binaries in the first phase and orbital period determinations in the second phase. Here we present first results of our ESO-VLT/FORS2 pilot study that targets the identification of the PCEBs among the fainter (g≳18.5) SDSS WDMS binaries. From published SDSS catalogues we selected 26 WDMS binaries to be observed with ESO-VLT/FORS2 in service mode. The design of the observations was to get two spectra per object separated by at least one night. We used the NaIλλ#3 doublet to measure radial velocity variations of our targets and a spectral decomposition/fitting technique to determine the white dwarf effective temperatures and surface gravities, masses, and secondary star spectral types for all WDMS binaries in our sample. Among the 26 observed WDMS binaries, we find 9 strong PCEB candidates showing clear (≥3σ) radial velocity variations, and we estimate the fraction of PCEBs among SDSS WDMS binaries to be ∼35±12%. We find indications of a dependence of the relative number of PCEBs among SDSS WDMS binaries on the spectral type of the secondary star. These results are subject to small number statistics and need to be confirmed by additional observations. Using Magellan-Clay/LDSS3, we measured the orbital periods of two PCEB candidates, SDSSJ1047+0523 and SDSSJ1414-0132, to be 9.17h and 17.48h, respectively. This pilot study demonstrates that our survey is highly efficient in identifying PCEBs among the SDSS WDMS binaries, and it will indeed provide the observational parameters that are needed to constrain the theoretical models of close binary evolution.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: novae, cataclysmic variables - stars: binaries: close

Simbad objects: 28

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Number of rows : 28

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 SDSS J001726.63-002451.2 WD* 00 17 26.6348887072 -00 24 51.475678762           DA+dMe 15 0
2 SDSS J022835.93-074032.4 WD* 02 28 35.9184448499 -07 40 32.436835811           DA+M 15 0
3 SDSS J032038.72-063823.0 WD* 03 20 38.7262002386 -06 38 22.913017516   18.7   18.9   DA+M 17 0
4 SDSS J081959.21+060424.2 WD* 08 19 59.17248 +06 04 23.7756   20.0   18.9   DA+M 15 0
5 SDSS J083354.84+070240.1 WD* 08 33 54.8568307340 +07 02 40.232050764           DA+M 19 0
6 CD-32 5613 WD* 08 41 32.4293043356 -32 56 32.916852010   12.07 11.85 12.3   DA5.5 257 0
7 SDSS J085542.49+044717.7 WD* 08 55 42.4982249343 +04 47 17.791932455           DA+M 12 0
8 SDSS J092451.63-001736.5 WD* 09 24 51.6362890885 -00 17 36.449063659           DA5+M: 17 0
9 SDSS J093904.03+051114.8 WD* 09 39 04.0372538765 +05 11 14.717597148           DA+M 11 0
10 SDSS J095108.74+025507.6 WD* 09 51 08.7406911363 +02 55 07.573749356           DA5+M: 16 0
11 2QZ J100953.7-002853 WD* 10 09 53.6825615227 -00 28 53.555190837   19.55       DA+M 18 0
12 SDSS J104358.59+060320.9 WD* 10 43 58.5989791430 +06 03 20.397113517           DA+M 13 0
13 SDSS J104738.24+052320.3 WD* 10 47 38.2442922264 +05 23 20.342958054           DA+M 15 0
14 SDSS J110151.34+122241.5 WD* 11 01 51.3377263147 +12 22 41.447997606           DA+M 13 0
15 2QZ J112623.8+010856 WD* 11 26 23.8797920565 +01 08 56.996429102           DA+M2 18 0
16 SDSS J122208.47+093406.2 WD* 12 22 08.4769936525 +09 34 06.289300496           DA+K 9 0
17 SDSS J125250.03-020608.2 WD* 12 52 50.0159543174 -02 06 08.340288206   19.25       DA+dMe 16 0
18 2QZ J141451.7-013243 WD* 14 14 51.7344208382 -01 32 42.791831250   19.31       DA+M 17 0
19 SDSS J142541.32+023047.4 WD* 14 25 41.3262146308 +02 30 47.442777535           DA+M 14 0
20 SDSS J150657.57-012021.7 WD* 15 06 57.5786148852 -01 20 21.676841181           DA+M 18 0
21 SDSS J204541.90-050925.7 WD* 20 45 41.9061982006 -05 09 25.701134705           DA+M 17 0
22 SDSS J205059.36-000254.2 WD* 20 50 59.3719707707 -00 02 54.325698928           DA+M 11 0
23 SDSS J212320.74+002455.5 WD* 21 23 20.7343475702 +00 24 55.579475169           DA+M 21 0
24 SDSS J215614.57-000237.3 WD* 21 56 14.5728814600 -00 02 37.452037089           D+M6 12 0
25 SDSS J220338.61-001750.8 WD* 22 03 38.6138365071 -00 17 50.793818377           DA+dMe 13 0
26 SDSS J231221.60+010127.0 WD* 23 12 21.61 +01 01 27.0           DB+M3 14 1
27 Feige 110 HS* 23 19 58.3995050606 -05 09 56.170282845 10.360 11.45 11.50 11.970 12.145 sdO8VIIIHe5 536 1
28 SDSS J232438.31-093106.5 ** 23 24 38.31264 -09 31 05.7252   18.3 18.63 18.5   DB+M 12 0

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2019.10.24-02:44:47

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