Precise Atmospheric Parameters for the Shortest Period Binary White Dwarfs: Gravitational Waves, Metals, and Pulsations

Abstract

We present a detailed spectroscopic analysis of 61 low mass white dwarfs and provide precise atmospheric parameters, masses, and updated binary system parameters based on our new model atmosphere grids and the most recent evolutionary model calculations. For the first time, we measure systematic abundances of He, Ca and Mg for metal-rich extremely low mass white dwarfs and examine the distribution of these abundances as a function of effective temperature and mass. Based on our preliminary results, we discuss the possibility that shell flashes may be responsible for the presence of the observed He and metals. We compare stellar radii derived from our spectroscopic analysis to model-independent measurements and find good agreement except for those white dwarfs with Teff < 10,000 K. We also calculate the expected gravitational wave strain for each system and discuss their significance to the eLISA space-borne gravitational wave observatory. Finally, we provide an update on the instability strip of extremely low mass white dwarf pulsators.

18 pages, 13 figures, 3 tables, accepted for publication in ApJ

References in corpus (80)

• A Massive Pulsar in a Compact Relativistic Binary
• The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment
• Long-Term Stability of Planets in Binary Systems
• A Tidally-Disrupted Asteroid Around the White Dwarf G29-38
• 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
• Are There Unstable Planetary Systems Around White Dwarfs?
• Ultraviolet Radiation from Evolved Stellar Populations -- I. Models
• The frequency of planetary debris around young white dwarfs
• Faint Thermonuclear Supernovae from AM Canum Venaticorum Binaries
• Spectroscopic Analysis of DA White Dwarfs: Stark Broadening of Hydrogen Lines Including Non-Ideal Effects
• A gaseous metal disk around a white dwarf
• A Comprehensive Spectroscopic Analysis of DB White Dwarfs
• Ancient planetary systems are orbiting a large fraction of white dwarf stars
• A Spectroscopic Survey & Analysis of Bright, Hydrogen-Rich White Dwarfs
• Infrared Signatures of Disrupted Minor Planets at White Dwarfs
• White Dwarf Mass Distribution in the SDSS
• A millisecond pulsar in a stellar triple system
• New evolutionary sequences for extremely low mass white dwarfs: Homogeneous mass and age determinations, and asteroseismic prospects
• Pollution of single white dwarfs by accretion of many small asteroids
• Spectroscopic analysis of DA white dwarfs with 3D model atmospheres
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• Externally-polluted white dwarfs with dust disks
• Debris Disks Around White Dwarfs: The DAZ Connection
• A 12 minute Orbital Period Detached White Dwarf Eclipsing Binary
• Carbon Deficiency in Externally-Polluted White Dwarfs: Evidence for Accretion of Asteroids
• The New Class of Dusty DAZ White Dwarfs
• The masses of the millisecond pulsar J1012+5307 and its white-dwarf companion
• Runaway accretion of metals from compact debris disks onto white dwarfs
• The ELM Survey. II. Twelve Binary White Dwarf Merger Systems
• Detailed compositional analysis of the heavily polluted DBZ white dwarf SDSS J073842.56+183509.06: A window on planet formation?
• The accretion-diffusion scenario for metals in cool white dwarfs
• Echoes of a decaying planetary system: the gaseous and dusty disks surrounding three white dwarfs
• Strengthening the Case for Asteroidal Accrection: Evidence for Subtle and Diverse Disks at White Dwarfs
• Rapid Orbital Decay in the 12.75-minute WD+WD Binary J0651+2844
• EL CVn-type binaries - Discovery of 17 helium white dwarf precursors in bright eclipsing binary star systems
• Multi-periodic pulsations of a stripped red giant star in an eclipsing binary
• The ELM Survey. IV. 24 White Dwarf Merger Systems
• Post-common envelope binaries from SDSS-X: The origin of low-mass white dwarfs
• The ELM Survey. V. Merging Massive White Dwarf Binaries
• The Frequency of Debris Disks at White Dwarfs
• SDSS J184037.78+642312.3: The First Pulsating Extremely Low Mass White Dwarf
• Towards an Empirical Determination of the ZZ Ceti Instability Strip
• HST/FGS Parallaxes of AM CVn Stars and Astrophysical Consequences
• A new class of pulsating white dwarf of extremely low mass: the fourth and fifth members
• The ELM Survey. III. A Successful Targeted Survey for Extremely Low Mass White Dwarfs
• Discovery of the Eclipsing Detached Double White Dwarf Binary NLTT 11748
• A Metal-Rich Low-Gravity Companion to a Massive Millisecond Pulsar
• A Helium White Dwarf of Extremely Low Mass
• Gaseous Material Orbiting the Polluted, Dusty White Dwarf HE1349-2305
• Rocky Planetesimals as the Origin of Metals in DZ Stars
• The Discovery of Binary White Dwarfs that will Merge within 500 Myr
• New Insights into the Problem of the Surface Gravity Distribution of Cool DA White Dwarfs
• Discovery of pulsations, including possible pressure modes, in two new extremely low mass, He-core white dwarfs
• Found: The Progenitors of AM CVn and Supernovae .Ia
• Solution to the problem of the surface gravity distribution of cool DA white dwarfs from improved 3D model atmospheres
• Discovery of an ultramassive pulsating white dwarf
• Precise parameters for both white dwarfs in the eclipsing binary CSS 41177
• CSS100603:112253-111037: A helium-rich dwarf nova with a 65 minute orbital period
• The (Double) White Dwarf Binary SDSS 1257+5428
• Discovery of a Bright, Extremely Low-Mass White Dwarf in a Close Double Degenerate System
• A New Gravitational Wave Verification Source
• Pure-hydrogen 3D model atmospheres of cool white dwarfs
• Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries
• Twins: The Two Shortest Period Non-Interacting Double Degenerate White Dwarf Stars
• Detection of a white dwarf companion to the white dwarf SDSSJ125733.63+542850.5
• Properties of the Eclipsing Double-White Dwarf Binary NLTT 11748
• A new extremely low-mass white dwarf in the NLTT catalogue
• LP 400-22, A very low-mass and high-velocity white dwarf
• SDSS J074511.56+194926.5: Discovery of a Metal-Rich and Tidally Distorted Extremely Low Mass White Dwarf
• Orbital properties of an unusually low-mass sdB star in a close binary system with a white dwarf
• Heavy metals in a light white dwarf: Abundances of the metal-rich, extremely low-mass GALEX J1717+6757
• Helium White Dwarfs in Cataclysmic Variables
• The Nature of Millisecond Pulsars with Helium White Dwarf Companions
• Spectroscopy of the inner companion of the pulsar PSR J0337+1715
• A Search for Pulsations in Helium White Dwarfs
• Two New Tidally Distorted White Dwarfs
• Radiative Levitation of Silicon in the Atmospheres of Two Hyades DA White Dwarfs
• The Runaway Binary LP 400-22 is Leaving the Galaxy
• Gaseous Debris Disks around White Dwarfs

Cited by in corpus (59)

• A $Gaia$ Data Release 2 catalogue of white dwarfs and a comparison with SDSS
• Hot subluminous stars
• New white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12
• New white dwarf stars in the Sloan Digital Sky Survey Data Release 10
• Pulsating white dwarfs: new insights
• Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing
• Hydrodynamic moving-mesh simulations of the common envelope phase in binary stellar systems
• White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 14
• Hot subdwarf binaries from the MUCHFUSS project - Analysis of 12 new systems and a study of the short-period binary population
• 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
• The ELM Survey. VIII. 98 Double White Dwarf Binaries
• Fundamental parameter accuracy of DA and DB white dwarfs in Gaia Data Release 2
• An unusual white dwarf star may be a surviving remnant of a subluminous Type Ia supernova
• 3D Model Atmospheres for Extremely Low-Mass White Dwarfs
• The ELM Survey. VI. Eleven New Double Degenerates
• The Gaia DR1 Mass-Radius Relation for White Dwarfs
• PSR J1738+0333: The First Millisecond Pulsar + Pulsating White Dwarf Binary
• A Refined Search for Pulsations in White Dwarf Companions to Millisecond Pulsars
• A Catalogue of Potential Post Common Envelope Binaries
• PSR J1012+5307: a millisecond pulsar with an extremely low-mass white dwarf companion
• A second case of outbursts in a pulsating white dwarf observed by Kepler
• Mixing and Overshooting in Surface Convection Zones of DA White Dwarfs: First Results from ANTARES
• The ELM Survey. IX. A Complete Sample of Low Mass White Dwarf Binaries in the SDSS Footprint
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: III. The pre-ELM white dwarf instability strip
• White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 16
• Sub-percent Photometry: Faint DA White Dwarf Spectophotometric Standards for Astrophysical Observatories
• Discovery of Three Pulsating, Mixed-atmosphere, Extremely Low-mass White Dwarf Precursors
• The ELM Survey South. II. Two dozen new low mass white dwarf binaries
• Searching for ZZ Ceti White Dwarfs in the Gaia Survey
• The Physical Nature of Subdwarf A Stars: White Dwarf Impostors
• The ELM Survey South. I. An Effective Search for Extremely Low Mass White Dwarfs
• Magnesium abundances in cool metal-polluted white dwarfs
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: II. Nonadiabatic analysis
• Discovery of a Detached, Eclipsing 40 min Period Double White Dwarf Binary and a Friend: Implications for He+CO White Dwarf Mergers
• Asteroseismic test of rotational mixing in low-mass white dwarfs
• A double white dwarf with a paradoxical origin?
• A 62-minute orbital period black widow binary in a wide hierarchical triple
• Influence of a mass transfer stability criterion on double white dwarf populations
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: IV. The secular rate of period change
• The Mass Distribution of Companions to Low-Mass White Dwarfs
• A New Merging Double Degenerate Binary in the Solar Neighborhood
• Mass-ratio distribution of extremely low-mass white dwarf binaries
• Pulsating low-mass white dwarfs in the frame of new evolutionary sequences: V. Asteroseismology of ELMV white dwarf stars
• A Model of the Pulsating Extremely Low-Mass White Dwarf Precursor WASP 0247-25B
• The McDonald Observatory search for pulsating sdA stars: asteroseismic support for multiple populations
• Four new deeply-eclipsing white dwarfs in ZTF
• Quantitative spectral analysis of the sdB star HD 188112: a helium-core white dwarf progenitor
• A long-period pre-ELM system discovered from LAMOST medium-resolution survey
• On the Correlation between Energy Spectra and Element Abundances in Solar Energetic Particles
• HS 2231+2441: an HW Vir system composed by a low-mass white dwarf and a brown dwarf
• HST+COS spectra of the double white dwarf CSS 41177 place the secondary inside the pulsational instability strip
• Post-common Envelope Evolution of Helium-core White Dwarfs
• The closest extremely low-mass white dwarf to the Sun
• Dark Matter-admixed Rotating White Dwarfs as Peculiar Compact Objects
• The collisional atomic processes of Rydberg alkali atoms in Geo-cosmical plasmas
• Exploring Temperature Influences on Gravitational Wave Production in Binary White Dwarfs
• Discovery of a Proto-White Dwarf with a Massive Unseen Companion
• Discovery of a double white dwarf in the Galactic globular cluster NGC 6397