Post-common envelope binaries from SDSS - III. Seven new orbital periods

Rebassa‐Mansergas, A.; Gänsicke, B. T.; Schreiber, M. R.; Southworth, J.; Schwope, A. D.; Gómez‐Morán, A. Nebot; Aungwerojwit, A.; Rodríguez‐Gil, P.; Karamanavis, V.; Krumpe, M.; Tremou, Evangelia; Schwarz, R.; Staude, Andreas; Vogel, J.

doi:10.1111/j.1365-2966.2008.13850.x

Cited by 12 publications

(5 citation statements)

References 48 publications

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“…Counting the SDSS sample with 3 200 systems and the LAMOST sample with 900 objects, both catalogues have been prolific at revealing a large number of radial velocity variable, i.e. PCEBs, and non-variable systems (Rebassa-Mansergas et al 2007, 2011Schreiber et al 2008Schreiber et al , 2010 -and the corresponding orbital period distributions (Rebassa-Mansergas et al 2008;Nebot Gómez-Morán et al 2011) -as well as of eclipsing binaries (Parsons et al 2012(Parsons et al , 2013(Parsons et al , 2015Pyrzas et al 2009Pyrzas et al , 2012Rebassa-Mansergas et al 2016a, 2019a.…”

Section: Introductionmentioning

confidence: 99%

White dwarf–main-sequence binaries from Gaia EDR3: the unresolved 100 pc volume-limited sample

Rebassa‐Mansergas

Solano

Jiménez-Esteban

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We use the data provided by the Gaia Early Data Release 3 to search for a highly-complete volume-limited sample of unresolved binaries consisting of a white dwarf and a main sequence companion (i.e. WDMS binaries) within 100 pc. We select 112 objects based on their location within the Hertzsprung-Russell diagram, of which 97 are new identifications. We fit their spectral energy distributions (SED) with a two-body fitting algorithm implemented in VOSA (Virtual Observatory SED Analyser) to derive the effective temperatures, luminosities and radii (hence surface gravities and masses) of both components. The stellar parameters are compared to those from the currently largest catalogue of close WDMS binaries, from the Sloan Digital Sky Survey (SDSS). We find important differences between the properties of the Gaia and SDSS samples. In particular, the Gaia sample contains WDMS binaries with considerably cooler white dwarfs and main sequence companions (some expected to be brown dwarfs). The Gaia sample also shows an important population of systems consisting of cool and extremely low-mass white dwarfs, not present in the SDSS sample. Finally, using a Monte Carlo population synthesis code, we find that the volume-limited sample of systems identified here seems to be highly complete (≃ 80 ± 9 per cent), however it only represents ≃9 per cent of the total underlying population. The missing ≃91 per cent includes systems in which the main sequence companions entirely dominate the SEDs. We also estimate an upper limit to the total space density of close WDMS binaries of ≃ (3.7 ± 1.9) × 10−4 pc−3.

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Section: Introductionmentioning

confidence: 99%

White dwarf–main-sequence binaries from Gaia EDR3: the unresolved 100 pc volume-limited sample

Rebassa‐Mansergas

Solano

Jiménez-Esteban

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…Conversely, if no RV variation is detected from spectra taken separated by at least one night, the system is considered as a likely wide binary candidate that presumably evolved avoiding episodes of mass transfer. We fit the Na I λλ 8183.27, 8194.81 absorption doublet with a second-order polynomial plus a double-Gaussian line profile of fixed separation, while the Hα emission line (if present in the spectrum) is fitted with a second-order polynomial plus a single-Gaussian line profile (Rebassa-Mansergas et al 2008;Ren et al 2013). With the aim of increasing the SN ratio, the final released LAMOST DR5 spectra are the result of combining several different sub-exposure spectra (hereafter sub-spectra).…”

Section: Identification Of Close Wdms Binariesmentioning

confidence: 99%

“…It has to be noted that the higher PCEB fraction derived by analysing the Hα RVs needs to be taken with caution. This is because Hα RVs are less robust for detecting RV variations due to magnetic activity effects (Rebassa-Mansergas et al 2008).…”

Section: Identification Of Close Wdms Binariesmentioning

confidence: 99%

“…Thus, the current most updated SDSS WDMS catalogue includes 3 294 binaries 1 , which is by far the largest and most homogeneous sample of compact binaries in the literature (Rebassa-Mansergas et al 2016a). Among the 3 294 SDSS WDMS, observational follow-up studies have resulted in the identification of ∼1000 wide binaries that did not interact and more than 200 PCEBs (Rebassa-Mansergas et al 2007;Schreiber et al 2008Schreiber et al , 2010Rebassa-Mansergas et al 2011, 2016a, of which 90 have available orbital periods (Rebassa-Mansergas et al 2008;Nebot Gómez-Morán et al 2011;Rebassa-Mansergas et al 2012b) and 71 are eclipsing (Nebot Gómez-Morán et al 2009;Pyrzas et al 2009Pyrzas et al , 2012Parsons et al 2013aParsons et al , 2015a.…”

Section: Introductionmentioning

confidence: 99%

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White dwarf–main sequence binaries from LAMOST: the DR5 catalogue

Ren

Rebassa‐Mansergas

Parsons

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present the data release (DR) 5 catalogue of white dwarf-main sequence (WDMS) binaries from the Large Area Multi-Object fiber Spectroscopic Telescope (LAMOST). The catalogue contains 876 WDMS binaries, of which 757 are additions to our previous LAMOST DR1 sample and 357 are systems that have not been published before. We also describe a LAMOST-dedicated survey that aims at obtaining spectra of photometrically-selected WDMS binaries from the Sloan Digital Sky Survey (SDSS) that are expected to contain cool white dwarfs and/or early type M dwarf companions. This is a population under-represented in previous SDSS WDMS binary catalogues. We determine the stellar parameters (white dwarf effective temperatures, surface gravities and masses, and M dwarf spectral types) of the LAMOST DR5 WDMS binaries and make use of the parameter distributions to analyse the properties of the sample. We find that, despite our efforts, systems containing cool white dwarfs remain under-represented. Moreover, we make use of LAMOST DR5 and SDSS DR14 (when available) spectra to measure the Na I λλ 8183.27, 8194.81 absorption doublet and/or Hα emission radial velocities of our systems. This allows identifying 128 binaries displaying significant radial velocity variations, 76 of which are new. Finally, we cross-match our catalogue with the Catalina Surveys and identify 57 systems displaying light curve variations. These include 16 eclipsing systems, two of which are new, and nine binaries that are new eclipsing candidates. We calculate periodograms from the photometric data and measure (estimate) the orbital periods of 30 (15) WDMS binaries.

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“…In particular, it has been shown that the early sample of well studied PCEBs is not only small but, being drawn mainly from "blue" quasar surveys, it is also heavily biased towards young systems with low-mass secondary stars (Schreiber & Gänsicke, 2003). However, the SDSS (Frieman et al, 2008;Abazajian et al, 2009) has allowed to identify a large number of WD+MS binaries (Heller et al, 2009;Rebassa-Mansergas et al, 2013), and a dedicated radial velocity survey among them has provided the so far largest and most homogeneous sample of close compact binaries with available orbital periods (Rebassa-Mansergas et al, 2008;Nebot Gómez-Morán et al, 2011). Hence, studying the populations of WD+MS binaries that have undergone a common envelope episode it is essential since the distribution of orbital periods and other characteristics of the populations, like the distributions of primary and secondary masses, can be used to constrain the values of the free parameters of the theory of common envelope evolution.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo simulations of the population of single and binary white dwarfs of our galaxy

Camacho Díaz

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Since white dwarfs are the final stage of the evolution of the vast majority of stars, they carry important information about the chemical evolution of our Galaxy, its star formation rate, and its structure and dynamics. This thesis pays attention to two related but distinct astrophysical problems involving white dwarfs. The first of these problems concern the nature and the location of the microlensing events towards the Large Magellanic Clouds (LMC), which still remains a mystery. The main observational groups, MACHO and EROS, are in dispute each, yet agreement has now been reached in some of the most important points. The second of the problems we address in this thesis is an open problem as well. Close compact binaries are at the heart of several interesting phenomena in our Galaxy as well. Close compact binaries are formed through at least one common envelope episode. Even though the basics concepts of the evolution during a common envelope phase are rather simple, the details are still far from being well understood. To shed light on these problems, we used an existing Monte Carlo simulator. We expanded this simulator integrating the most up-to-date white dwarfs cooling models as well as detailed modeling of our Galaxy and the LMC in order to mimic both the MACHO and EROS experiments. Additionally, we included the red dwarf population and performed a joint analysis of the contributions of both populations to the dark matter content of our Galaxy. Moreover, we studied the contribution of the subpopulation of white dwarfs with hydrogen-deficient atmospheres. On the other hand, our Monte Carlo code has been expanded to deal with those systems composed by a white dwarf and a main sequence star, which have evolved through a common episode. A detailed implementation of several different physical processes, including a full description of the mass transfer episode, a complete treatment of the Roche lobe overflow episode, gravitational tides and orbital evolution of the binary system, was performed. Furthermore, in our treatment we carefully included all the different selection criteria and observational biases. This allowed us to make a meaningful comparison with the available data, besides examining the role played by the binding energy parameter and by the common envelope parameter, not to mention the role played by the distribution of secondary masses of the binary systems. The results of our Monte Carlo simulations of the microlensing experiments show agreement with the findings of the EROS and MACHO survey. Our findings show that neither white dwarfs nor red dwarfs can be major contributors to the microlensing depth towards the LMC. These facts reinforce the idea, previously pointed by others studies, that the optical depth found by the MACHO survey is highly likely an overestimate, probably due to contamination of self-lensing objects, amid other possible explanations. Concerning the second point of this thesis, our Monte Carlo simulations correctly reproduce the properties of the observed population of post-common envelope white dwarf plus main sequence binaries, once biases are taken into account. The best-fit models are obtained with fractions less than ~20% of the internal energy contributing to the ejection of the star progenitor¿s envelope, and values for the common-envelope efficiency parameter less than ~0.3. To conclude, the work presented in this thesis poses an important step forward not only in constraining the microlensing discoveries, but also in validating models for the observed white-dwarf populations of our Galaxy.

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Post-common envelope binaries from SDSS - III. Seven new orbital periods

Cited by 12 publications

References 48 publications

White dwarf–main-sequence binaries from Gaia EDR3: the unresolved 100 pc volume-limited sample

White dwarf–main-sequence binaries from Gaia EDR3: the unresolved 100 pc volume-limited sample

White dwarf–main sequence binaries from LAMOST: the DR5 catalogue

Monte Carlo simulations of the population of single and binary white dwarfs of our galaxy

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