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

Aungwerojwit, A.; Gänsicke, B. T.; Rodríguez‐Gil, P.; Hagen, H. J.; Giannakis, Omiros; Papadimitriou, Christos; Prieto, C. Allende; Engels, D.

doi:10.1051/0004-6361:20077276

Cited by 24 publications

(27 citation statements)

References 48 publications

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“…To explore the parameter space we enlarged the sample by taking the PCEB lists of Morales-Rueda et al (2005) and Shimansky et al (2006), examined the published data on these systems, and included HS 1857+5144 (Aungwerojwit et al 2007). Since our main interest concerns potential precataclysmic variables such as LTT 560, we limited the sample to PCEBs with P orb < 1 d that contain a white dwarf as primary component.…”

Section: Discussionmentioning

confidence: 99%

Multiple emission line components in detached post-common-envelope binaries

Tappert

Gänsicke

Rebassa‐Mansergas

et al. 2011

A&A

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Motivated by the recent discovery of an Hα emission line component originating close to the white dwarf primary in the post-commonenvelope binary (PCEB) LTT 560, we have undertaken a spectroscopic snapshot survey on 11 short-period (P orb < 6 h) PCEBs using FORS2. We have found multi-component Hα emission line profiles in six of our targets, indicating that multiple Hα emission sites are rather common in short-period PCEBs. The underlying physical mechanisms, however, can be fundamentally different. In our sample we find one system where the extracted radial velocities of two identified components indicate that both originate in the late-type secondary star, where one is caused by irradiation from the hot white dwarf primary and the other by stellar activity. Another object presents two components that are located on opposite sides of the centre-of-mass, suggesting a case similar to LTT 560, i.e. that accretion of stellar wind from the secondary star produces Hα emission on, or close to, the white dwarf.

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Section: Discussionmentioning

confidence: 99%

Multiple emission line components in detached post-common-envelope binaries

Tappert

Gänsicke

Rebassa‐Mansergas

et al. 2011

A&A

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“…An accurate estimate of the masses of the components of these systems needs radial velocities; we are in the process of collecting such data through spectroscopic observations with GMOS at GEM-INI South. It is noteworthy that the V−I color of the variable is constant (see Figure 4), which means that we cannot be observing a reflection effect, i.e., the heated hemisphere of the MS companion as in the case of the WD-MS binary HS 1857+5144 (Aungwerojwit et al 2007). This ellipsoidal variable is relatively bright with F 606W ∼ 21.6 mag; stars belonging to the reddest WD cooling sequence could be the fainter counterparts of this object.…”

Section: Binaries As Precursors Of He-core Wdsmentioning

confidence: 91%

First Detection of the White Dwarf Cooling Sequence of the Galactic Bulge

Calamida¹,

Sahu²,

Anderson³

et al. 2014

ApJ

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We present Hubble Space Telescope data of the low-reddening Sagittarius window in the Galactic bulge. The Sagittarius Window Eclipsing Extrasolar Planet Search field (∼3 × 3 ), together with three more Advanced Camera for Surveys and eight Wide-Field Camera 3 fields, were observed in the F 606W and F 814W filters, approximately every two weeks for 2 yr, with the principal aim of detecting a hidden population of isolated black holes and neutron stars through astrometric microlensing. Proper motions were measured with an accuracy of ≈0.1 mas yr −1 (≈4 km s −1 ) at F 606W ≈ 25.5 mag, and better than ≈0.5 mas yr −1 (≈20 km s −1 ) at F 606W ≈ 28 mag, in both axes. Proper-motion measurements allowed us to separate disk and bulge stars and obtain a clean bulge color-magnitude diagram. We then identified for the first time a white dwarf (WD) cooling sequence in the Galactic bulge, together with a dozen candidate extreme horizontal branch stars. The comparison between theory and observations shows that a substantial fraction of the WDs (≈30%) are systematically redder than the cooling tracks for CO-core H-rich and He-rich envelope WDs. This evidence would suggest the presence of a significant number of low-mass WDs and WD-main-sequence binaries in the bulge. This hypothesis is further supported by the finding of two dwarf novae in outburst, two short-period (P 1 day) ellipsoidal variables, and a few candidate cataclysmic variables in the same field.

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“…White dwarf plus main sequence (WDMS) binaries are a perfect test laboratory for studying the current population synthesis models, because they are numerous, their stellar components are well understood in terms of their single evolution and they are not accreting, which would increase the complexity. The number of PCEBs with well-defined parameters is still small, although it has increased since Schreiber & Gänsicke (2003), from 30 to almost 50 systems (Gänsicke et al 2004;Morales-Rueda et al 2005;Shimansky et al 2006;van den Besselaar et al 2007;Aungwerojwit et al 2007;Tappert et al 2007;Schreiber et al 2008;Rebassa-Mansergas et al 2008;Steinfadt et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Post common envelope binaries from SDSS

Gómez‐Morán¹,

Schwope²,

Schreiber

et al. 2009

A&A

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From optical photometry we show that SDSS J121258.25-012310.1 is a new eclipsing, post common-envelope binary with an orbital period of 8.06 h and an eclipse length of 23 min. We observed the object over 11 nights in different bands and determined the ephemeris of the eclipse to HJD mid = 2 454 104.7086(2) + 0.3358706(5) × E, where numbers in parenthesis indicate the uncertainties in the last digit. The depth of the eclipse is 2.85 ± 0.17 mag in the V band, 1.82 ± 0.08 mag in the R band and 0.52 ± 0.02 mag in the I band. From spectroscopic observations we measured the semi-amplitude of the radial velocity K 2 = 181± 3 km s −1 for the secondary star. The stellar and binary parameters of the system were constrained from a) fitting the SDSS composite spectrum of the binary, b) using a K-band luminosty-mass relation for the secondary star, and c) from detailed analyses of the eclipse light curve. The white dwarf has an effective temperature of 17 700 ± 300 K, and its surface gravity is log g = 7.53 ± 0.2. We estimate that the spectral type of the red dwarf is M4 ± 1 and the distance to the system is 230 ± 20 parsec. The mass of the secondary star is estimated to be in the range M sec = 0.26−0.29 M , while the mass of the white dwarf is most likely M wd = 0.46−0.48 M . From an empirical mass-radius relation we estimate the radius of the red dwarf to be in the range 0.28−0.31 R , whereas we get R wd = 0.016−0.018 R from a theoretical mass-radius realation. Finally we discuss the spectral energy distribution and the likely evolutionary state of SDSS1212-0123.

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

Cited by 24 publications

References 48 publications

Multiple emission line components in detached post-common-envelope binaries

Multiple emission line components in detached post-common-envelope binaries

First Detection of the White Dwarf Cooling Sequence of the Galactic Bulge

Post common envelope binaries from SDSS

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