The ELM Survey South. II. Two dozen new low mass white dwarf binaries

Abstract

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 white dwarfs, one short period, likely eclipsing, DABZ, and two potential LISA binaries. We present orbital and atmospheric parameters for each new binary based on our spectroscopic follow-up. Four of our new binaries show periodic photometric variability in the TESS 2-minute 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 to 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 the 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.

arXiv comment28 pages. 13 Figures, 5 Tables. Accepted for publication in The Astrophysical Journal

References in corpus (70)

• Astropy: A Community Python Package for Astronomy
• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The Transiting Exoplanet Survey Satellite
• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• Local Kinematics and the Local Standard of Rest
• Understanding the Lomb-Scargle Periodogram
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• A box-fitting algorithm in the search for periodic transits
• The First Data Release of the Sloan Digital Sky Survey
• Preliminary Results from NEOWISE: An Enhancement to the Wide-field Infrared Survey Explorer for Solar System Science
• The Zwicky Transient Facility: Science Objectives
• The TESS Input Catalog and Candidate Target List
• Kinematics of Metal-Poor Stars in the Galaxy. III. Formation of the Stellar Halo and Thick Disk as Revealed from a Large Sample of Non-Kinematically Selected Stars
• RVSAO 2.0: Digital Redshifts and Radial Velocities
• The gravitational wave signal from the Galactic disk population of binaries containing two compact objects
• The Formation Rate, Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey
• Eclipsing binaries in open clusters. II. V453 Cyg in NGC 6871
• A Spectroscopic Survey & Analysis of Bright, Hydrogen-Rich White Dwarfs
• On the Spectral Evolution of Hot White Dwarf Stars. I. A Detailed Model-Atmosphere Analysis of Hot White Dwarfs from SDSS DR12
• New evolutionary sequences for extremely low mass white dwarfs: Homogeneous mass and age determinations, and asteroseismic prospects
• SkyMapper Southern Survey: Second Data Release (DR2)
• Prospects for detection of detached double white dwarf binaries with Gaia, LSST and LISA
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing
• General relativistic orbital decay in a seven-minute-orbital-period eclipsing binary system
• Physical properties of IP Pegasi: an eclipsing dwarf nova with an unusually cool white dwarf
• The ELM Survey. II. Twelve Binary White Dwarf Merger Systems
• Characterizing the Galactic Gravitational Wave Background with LISA
• The solar-type eclipsing binary system LL Aquarii
• The ELM Survey. VII. Orbital Properties of Low Mass White Dwarf Binaries
• A systematic search of Zwicky Transient Facility data for ultracompact binary LISA-detectable gravitational-wave sources
• Every interacting double white dwarf binary may merge
• The ELM Survey. VIII. 98 Double White Dwarf Binaries
• Measurements of Physical Parameters of White Dwarfs: A Test of the Mass-Radius Relation
• The ELM Survey. IV. 24 White Dwarf Merger Systems
• The Future is Now: the Formation of Single Low Mass White Dwarfs in the Solar Neighborhood
• The ELM Survey. V. Merging Massive White Dwarf Binaries
• Formation of Extremely Low-mass White Dwarfs in Double Degenerates
• HST/FGS Parallaxes of AM CVn Stars and Astrophysical Consequences
• The ELM Survey. III. A Successful Targeted Survey for Extremely Low Mass White Dwarfs
• 3D Model Atmospheres for Extremely Low-Mass White Dwarfs
• Testing common classical LTE and NLTE model atmosphere and line-formation codes for quantitative spectroscopy of early-type stars
• Precise Atmospheric Parameters for the Shortest Period Binary White Dwarfs: Gravitational Waves, Metals, and Pulsations
• The ELM Survey. VI. Eleven New Double Degenerates
• Post-merger evolution of carbon-oxygen + helium white dwarf binaries and the origin of R Coronae Borealis and extreme helium stars
• Most Double Degenerate Low Mass White Dwarf Binaries Merge
• Gaia Data Release 2 Catalogue of Extremely-low Mass White Dwarf Candidates
• Solution to the problem of the surface gravity distribution of cool DA white dwarfs from improved 3D model atmospheres
• Precise parameters for both white dwarfs in the eclipsing binary CSS 41177
• White dwarf binaries suggest a common envelope efficiency $\alpha \sim 1/3$
• Gravity and limb-darkening coefficients for compact stars: DA, DB, and DBA eclipsing white dwarfs
• Year 1 of the ZTF high-cadence Galactic Plane Survey: Strategy, goals, and early results on new single-mode hot subdwarf B-star pulsators
• Identifying LISA verification binaries among the Galactic population of double white dwarfs
• Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries
• The Merger Fraction of Ultramassive White Dwarfs
• The ELM Survey. IX. A Complete Sample of Low Mass White Dwarf Binaries in the SDSS Footprint
• Gravitational Wave Radiation of Double Degenerates with Extremely low-mass WD companions
• A proto-helium white dwarf stripped by a substellar companion via common-envelope ejection -- Uncovering the true nature of a candidate hypervelocity B-type star
• The ELM Survey South. I. An Effective Search for Extremely Low Mass White Dwarfs
• ZTF J1901+5309: A 40.6-Minute Orbital Period Eclipsing Double White Dwarf System
• Extremely low-mass white dwarf stars observed in Gaia DR2 and LAMOST DR8
• $\gamma$ Columbae: the recently stripped, pulsating core of a massive star
• Two new Double-lined Spectroscopic Binary White Dwarfs
• Massive Double White Dwarfs and the AM CVn Birthrate

Cited by in corpus (10)

• On the optical transients from double white-dwarf mergers
• J0526+5934: a peculiar ultra-short period double white dwarf
• The first phase of mass transfer in low-mass binaries: neither stable nor a common envelope
• Extreme mass loss during common envelope evolution: the origin of the double low-mass white dwarf system J2102--4145
• Precise Parameters for Two LISA Sources
• Comparing population synthesis models of compact double white dwarfs to electromagnetic observations
• Searching for new variable white dwarfs: The discovery of the three new pulsating and three new binary systems
• Double white dwarf binary population in MOCCA star clusters -- Comparisons with observations of close and wide binaries
• Formation of Extremely Low-mass White Dwarf Binaries Undergoing Enhanced Angular Momentum Loss
• Tidal heating in detached double white dwarf binaries