The origin of single low-mass WDs: another problem that consequential angular momentum loss in CVs might solve

Abstract

Low-mass helium-core white-dwarfs (WDs) with masses below 0.5 Msun are known to be formed in binary star systems but unexpectedly a significant fraction of them seem to be single. On the other hand, in Cataclysmic Variables (CVs) a large number of low-mass WD primary stars is predicted but not observed. We recently showed that the latter problem can be solved if consequential angular momentum loss causes especially CVs with low-mass WDs to merge and form single stars. Here we simulate the population of single WDs resulting from single star evolution and from binary star mergers taking into account these new merging CVs. We show that according to the revised model of CV evolution, merging CVs might be the dominant channel leading to the formation of low-mass single WDs and that the predicted relative numbers are consistent with observations. This can be interpreted as further evidence for the revised model of CV evolution we recently suggested. This model includes consequential angular momentum loss that increases with decreasing WD mass and might not only explain the absence of low-mass WD primaries in CVs but also the existence of single low-mass WDs.

5 pages, 3 figures. Accepted for publication in MNRAS

References in corpus (35)

• The Seventh Data Release of the Sloan Digital Sky Survey
• Evolution of binary stars and the effect of tides on binary populations
• Comprehensive analytic formulae for stellar evolution as a function of mass and metallicity
• Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample
• The Evolution of Cataclysmic Variables as Revealed by their Donor Stars
• Asteroseismology of old open clusters with Kepler: direct estimate of the integrated RGB mass loss in NGC6791 and NGC6819
• White Dwarf Mass Distribution in the SDSS
• Stellar Multiplicity and the IMF: Most Stars Are Single
• Post-common-envelope binaries from SDSS. IX: Constraining the common-envelope efficiency
• Post-common-envelope binaries from SDSS. XI: The white dwarf mass distributions of CVs and pre-CVs
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• The fastest unbound star in our Galaxy ejected by a thermonuclear supernova
• The Field White Dwarf Mass Distribution
• Three in one go: consequential angular momentum loss can solve major problems of CV evolution
• Stellar Evolution in NGC 6791: Mass Loss on the Red Giant Branch and the Formation of Low Mass White Dwarfs
• Origin of apparent period variations in eclipsing post-common-envelope binaries
• On type Ia supernovae and the formation of single low-mass white dwarfs
• The massive star binary fraction in young open clusters - II. NGC 6611 (Eagle Nebula)
• The Future is Now: the Formation of Single Low Mass White Dwarfs in the Solar Neighborhood
• Post-common envelope binaries from SDSS-X: The origin of low-mass white dwarfs
• Common Envelope Evolution Redux
• Companion stars of Type Ia supernovae and hypervelocity stars
• Initial-Final Mass Relationship for Stars of Different Metallicities
• Evolution of white dwarf stars with high-metallicity progenitors: the role of 22Ne diffusion
• The formation of Cataclysmic Variables: the influence of nova eruptions
• The Binary Fraction of Low Mass White Dwarfs
• Monte Carlo simulations of post-common-envelope white dwarf + main sequence binaries: The effects of including recombination energy
• Detached cataclysmic variables are crossing the orbital period gap
• Beryllium in turnoff stars of NGC6397: early Galaxy spallation, cosmochronology and cluster formation
• Population synthesis of Galactic subdwarf B stars
• White dwarf masses in cataclysmic variables
• White Dwarfs in NGC 6791: Avoiding the Helium Flash
• The evolution of the self-lensing binary KOI-3278: evidence of extra energy sources during CE evolution
• Helium White Dwarfs in Cataclysmic Variables
• The white dwarf cooling sequence of NGC 6791: a unique tool for stellar evolution

Cited by in corpus (25)

• A Volume Limited Sample of Cataclysmic Variables from $Gaia$ DR2: Space Density and Population Properties
• Constraining the Evolution of Cataclysmic Variables via the Masses and Accretion Rates of their Underlying White Dwarfs
• The ESO supernovae type Ia progenitor survey (SPY)
• The evolutionary status of Cataclysmic Variables: Eclipse modelling of 15 systems
• Evidence for reduced magnetic braking in polars from binary population models
• Alone but not lonely: Observational evidence that binary interaction is always required to form hot subdwarf stars
• Two white dwarfs in ultrashort binaries with detached, eclipsing, likely substellar companions detected by K2
• MOCCA-SURVEY database I. Accreting white dwarf binary systems in globular clusters -- IV. cataclysmic variables -- properties of bright and faint populations
• Close detached white dwarf + brown dwarf binaries: further evidence for low values of the common envelope efficiency
• No cataclysmic variables missing: higher merger rate brings into agreement observed and predicted space densities
• The binary fraction, separation distribution, and merger rate of white dwarfs from SPY
• Cataclysmic variable evolution and the white dwarf mass problem: A Review
• Galactic Model Parameters and Space Density of Cataclysmic Variables in Gaia Era: New Constraints to Population Models
• HE 0430-2457: a post merger extremely low-mass pre-white dwarf in a wide binary posing as an extreme horizontal branch star
• Are white dwarf magnetic fields in close binaries generated during common-envelope evolution?
• MOCCA-SURVEY database I. Accreting white dwarf binary systems in globular clusters -- III. Cataclysmic variables -- Implications of model assumptions
• Transients from the Cataclysmic Deaths of Cataclysmic Variables
• A strange star scenario for the formation of isolated millisecond pulsars
• Further evidence of saturated, boosted, and disrupted magnetic braking from evolutionary tracks of cataclysmic variables
• Evolution models of helium white dwarf--main-sequence star merger remnants: the mass distribution of single low-mass white dwarfs
• Search for magnetic accretion in SW Sextantis systems
• The C/N ratio from FUV spectroscopy as a constraint upon the past evolution of HS0218+3229
• Resolution of a paradox: SDSS J1257+5428 can be explained as a descendant of a cataclysmic variable with an evolved donor
• A candidate magnetic helium core white dwarf in the globular cluster NGC 6397
• Searching for new variable white dwarfs: The discovery of the three new pulsating and three new binary systems