Extremely Low-mass White Dwarf Stars Observed in Gaia DR2 and LAMOST DR8

Wang, Kun; Németh, P.; Luo, Yangping; Chen, Xiaodian; Jiang, Qing-Quan; Cao, Xingmei

doi:10.3847/1538-4357/ac847c

Cited by 13 publications

(7 citation statements)

References 69 publications

(111 reference statements)

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“…Many of the remaining binaries not reported as ELM white dwarf candidates in Pelisoli & Vos (2019) were excluded in their color cuts used to remove cataclysmic variables and white dwarf + M dwarf binary contaminants. Wang et al (2022) used LAMOST DR8 low-resolution spectroscopy to refine the candidate list of Pelisoli & Vos (2019) further and identified 21 high-probability ELM white dwarfs based on spectroscopic fits to the low-resolution LAMOST data, including two of the new binaries we present in this work. Wang et al (2022) identified J0215+0155 with atmospheric parameters of T eff = 10,540 ± 40 K and , and v rad,2 = 94.9 ± 5.4 km s −1 , the first of which is in excellent agreement with the atmospheric parameter estimates from the fits presented in this work.…”

Section: Comparison With Other Surveysmentioning

confidence: 99%

“…In total, previous ELM Survey studies have constrained the orbits and atmospheric parameters of 120 unique low-mass white dwarf binaries (Brown et al 2020;Kosakowski et al 2020;Brown et al 2022). Similar studies have created catalogs of ELM white dwarf candidates using Gaia DR2 astrometry (see Pelisoli & Vos 2019) and single-epoch spectroscopy from LAMOST DR8 (see Wang et al 2022), many of which still require follow-up observations to confirm their nature.…”

Section: Introductionmentioning

confidence: 99%

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The ELM Survey South. II. Two Dozen New Low-mass White Dwarf Binaries

Kosakowski

Brown

Kilic

et al. 2023

ApJ

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We present the results from our ongoing spectroscopic survey targeting low-mass white dwarf binaries, focusing on the southern sky. We used a Gaia DR2- and eDR3-based selection and identified 28 new binaries, including 19 new extremely low-mass (ELM) white dwarfs, one short period, likely eclipsing, DABZ, and two potential LISA binaries. We present the orbital and atmospheric parameters for each new binary based on our spectroscopic follow up. Four of our new binaries show periodic photometric variability in TESS 2 minutes cadence data, including one new eclipsing double-lined spectroscopic binary. Three others show periodic photometric variability in ZTF, including one new eclipsing binary. We provide estimates for the inclinations and scaled component radii for these ZTF variables, based on light-curve modeling of our high-speed photometric follow-up observations. Our observations have increased the sample of ELM Survey binaries identified in the southern sky to 41, an increase of 64%. Future time domain surveys, such as BlackGEM and the Vera C. Rubin Observatory Legacy Survey of Space and Time, will efficiently identify photometric variables in the southern sky and significantly increase the population of southern sky low-mass white dwarf binaries, leading to a more complete all-sky population of these systems.

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Section: Comparison With Other Surveysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The ELM Survey South. II. Two Dozen New Low-mass White Dwarf Binaries

Kosakowski

Brown

Kilic

et al. 2023

ApJ

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“…There are currently more than 150 known ELM WDs (e.g. Brown et al 2022;Kosakowski et al 2023, and references therein), as well as ELM WD candidates (Pelisoli & Vos 2019;Wang et al 2022).…”

Section: Introductionmentioning

confidence: 99%

The double low-mass white dwarf eclipsing binary system J2102–4145 and its possible evolution

Antunes Amaral,

Munday,

Vučković

et al. 2024

A&A

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In recent years, about 150 low-mass white dwarfs (WDs), typically with masses below $0.4M_ odot $, have been discovered. The majority of these low-mass WDs are observed in binary systems as they cannot be formed through single-star evolution within Hubble time. In this work, we present a comprehensive analysis of the double low-mass WD eclipsing binary system J2102-4145. Our investigation encompasses an extensive observational campaign, resulting in the acquisition of approximately 28 hours of high-speed photometric data across multiple nights using NTT/ULTRACAM, SOAR/Goodman, and SMARTS-1m telescopes. These observations have provided critical insights into the orbital characteristics of this system, including parameters such as inclination and orbital period. To disentangle the binary components of J2102-4145, we employed the GRID spectral fitting method with GMOS/Gemini-South and X-Shooter data. Additionally, we used the PHOEBE package for light curve analysis on NTT/ULTRACAM high-speed time-series photometry data to constrain the binary star properties. Our analysis unveils remarkable similarities between the two components of this binary system. For the primary star, we determine $T_ eff,1 $ K, $ g_1 = 7.36 $R_1=0.0211 and $M_1 = 0.375 odot $, while, the secondary star is characterised by $T_ eff,2 $ K, $ g_2 = 7.32 $\,R$_ and $M_2 = 0.314 odot $. Furthermore, we found a notable discrepancy between $T_ eff $ and $R$ of the less massive WD, compared to evolutionary sequences for WDs from the literature, which has significant implications for our understanding of WD evolution. We discuss a potential formation scenario for this system which might explain this discrepancy and explore its future evolution. We predict that this system will merge in sim 800\,Myr, evolving into a helium-rich hot subdwarf star and later into a hybrid He/CO WD.

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“…In addition to searches from individual observations, one can perform a CWDB search with a larger scale. Several surveys can be used to pick potential CWDB candidates, like the Catalina Real-time Transient Survey (CRTS; Breedt et al 2014), the Global Astrometric Interferometer for Astrophysics (Gaia; Geier et al 2017;El-Badry et al 2021a;Gentile Fusillo et al 2021;Rebassa-Mansergas et al 2021;Torres et al 2022), the Optical Gravitational Lensing Experiment (Wevers et al 2016), the Palomar Transient Factory (van Roestel et al 2017(van Roestel et al , 2018Burdge et al 2019b), the All Sky Automated Survey for SuperNovae (Rivera Sandoval et al 2022), the Transit Exoplanet Survey Satellite (Wang et al 2020;Pichardo Marcano et al 2021;Hernandez et al 2022), the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST; Wang et al 2022b), and most recently the Zwicky Transient Facility (ZTF; Burdge et al 2020aBurdge et al , 2020bCoughlin et al 2020;Ofek et al 2020;Szkody et al 2020;Kupfer et al 2021;Szkody et al 2021;Keller et al 2022;McWhirter & Lam 2022). Repeated observations of the same sources can reveal optical variability, and some of these surveys can be used, and have been used, to determine the periodicity.…”

Section: Introductionmentioning

confidence: 99%

A Systematic Search for Short-period Close White Dwarf Binary Candidates Based on Gaia EDR3 Catalog and Zwicky Transient Facility Data

Ren¹,

Li²,

Ma³

et al. 2023

ApJS

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Galactic short-period close white dwarf binaries (CWDBs) are important objects for space-borne gravitational-wave (GW) detectors in the millihertz frequency bands. Due to the intrinsically low luminosity, only about 25 identified CWDBs are detectable by the Laser Interferometer Space Antenna (LISA), which are also known as verification binaries (VBs). The Gaia Early Data Release 3 (EDR3) provids a catalog containing a large number of CWDB candidates, which also includes parallax and photometry measurements. We crossmatch the Gaia EDR3 and Zwicky Transient Facility public data release 8, and apply period-finding algorithms to obtain a sample of periodic variables. The phase-folded light curves are inspected, and finally we obtain a binary sample containing 429 CWDB candidates. We further classify the samples into eclipsing binaries (including 58 HW Vir-type binaries, 65 EA-type binaries, 56 EB-type binaries, and 41 EW-type binaries) and ellipsoidal variations (209 ELL-type binaries). We discovered four ultrashort period binary candidates with unique light-curve shapes. We estimate the GW amplitude of all of our binary candidates, and calculate the corresponding signal-to-noise ratio (S/N) for TianQin and LISA. We find two (six) potential GW candidates with S/Ns greater than 5 in the nominal mission time of TianQin (LISA), which increases the total number of candidate VBs for TianQin (LISA) to 18 (31).

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Extremely Low-mass White Dwarf Stars Observed in Gaia DR2 and LAMOST DR8

Cited by 13 publications

References 69 publications

The ELM Survey South. II. Two Dozen New Low-mass White Dwarf Binaries

The ELM Survey South. II. Two Dozen New Low-mass White Dwarf Binaries

The double low-mass white dwarf eclipsing binary system J2102–4145 and its possible evolution

A Systematic Search for Short-period Close White Dwarf Binary Candidates Based on Gaia EDR3 Catalog and Zwicky Transient Facility Data

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