A unified model for the evolution of cataclysmic variables

Abstract

We give an updated version of the analytical equation of state used in the Cambridge stellar evolution code (STARS) as a free to use open-source package that we have used to model cool white dwarfs down to temperatures ${\log }_{10}(T_{\mathrm{eff}}/\mathrm{K})=3$. With this update in the STARS code we model the secular evolution of cataclysmic variable (CV) stars using a double dynamo model wherein there is an interplay between two $\alpha -\Omega$ dynamos, one in the convective envelope and the other at the boundary of a slowly rotating shrinking radiative core and the growing convective envelope. We confirm that this model provides a physical formalism for the interrupted magnetic braking paradigm. In addition, our model also provides a mechanism for extra angular momentum loss below the period gap. We construct the relative probability distribution of orbital periods $P_{\mathrm{orb}}$ using the {mass} distribution of white dwarfs in cataclysmic variables and find that our model excellently reproduces the period gap and the observed period minimum spike in CV distribution. We also compare the evolutionary trajectories from our model with those of other empirical models and find agreement between the two. We also report good agreement between our modelled systems and observational data.

arXiv commentAccepted for publication in MNRAS

References in corpus (13)

• Catalogue of cataclysmic binaries, low-mass X-ray binaries and related objects (Seventh edition)
• The Evolution of Cataclysmic Variables as Revealed by their Donor Stars
• Approximate input physics for stellar modelling
• The Donor Stars of Cataclysmic Variables
• On the formation and evolution of black-hole binaries
• SDSS unveils a population of intrinsically faint cataclysmic variables at the minimum orbital period
• Post-common-envelope binaries from SDSS. XI: The white dwarf mass distributions of CVs and pre-CVs
• A Volume Limited Sample of Cataclysmic Variables from $Gaia$ DR2: Space Density and Population Properties
• Adiabatic Mass Loss in Binary Stars. II. From Zero-Age Main Sequence to the Base of the Giant Branch
• Population Synthesis of Cataclysmic Variables: I. Inclusion of Detailed Nuclear Evolution
• Evolution of Cataclysmic Variables and Related Binaries Containing a White-Dwarf
• Rotation rate of the solar core as a key constraint to magnetic angular momentum transport in stellar interiors
• White dwarf masses in cataclysmic variables

Cited by in corpus (10)

• Galactic Model Parameters and Space Density of Cataclysmic Variables in Gaia Era: New Constraints to Population Models
• Reversing the verdict: Cataclysmic variables could be the dominant progenitors of AM CVn binaries after all
• Evolved cataclysmic variables as progenitors of AM CVn stars
• New insights into the helium star formation channel of AM CVn systems with explanations of Gaia14aae and ZTFJ1637+49
• Towards a holistic magnetic braking model from the evolution of cataclysmic variables to stellar spin-down -- I: the spin-down of fully convective M-dwarfs
• Magnetic braking below the cataclysmic variable period gap and the observed dearth of period bouncers
• Convective dynamos of black widow companions
• Towards a holistic magnetic braking model -- II: explaining several long-term internal- and surface-spin properties of solar-like stars and the Sun
• White Dwarf Mass Growth in Cataclysmic Variables: Roles of Dwarf Novae
• Mechanisms for magnetic braking boost and disruption: the role of irradiation-driven winds and convective turnover time spike in cataclysmic variables