The cataclysmic variable QZ Lib: a period bouncer

Abstract

While highly evolved cataclysmic variables (CVs) with brown dwarf donors, often called "period bouncers", are predicted to make up $\simeq 40-70$ % of the Galactic CV population, only a handful of such systems are currently known. The identification and characterization of additional period bouncers is therefore important to probe this poorly understood phase of CV evolution. We investigate the evolution of the CV QZ Lib following its 2004 super-outburst using multi-epoch spectroscopy. From time-resolved spectroscopic observations we measure the orbital period of the system, $P_{\mathrm{orb}}=0.06436(20)$ d, which, combined with the superhump period $P_{\mathrm{SH}}=0.064602(24)$ d, yields the system mass ratio, $q=0.040(9)$. From the analysis of the spectral energy distribution we determine the structure of the accretion disc and the white dwarf effective temperature, $T_{\mathrm{eff}}=10500\pm 1500\mathrm{K}$. We also derive an upper limit on the effective temperature of the secondary, $T_{\mathrm{eff}}\lesssim 1700\mathrm{K}$, corresponding to a brown dwarf of T spectral type. The low temperature of the white dwarf, the small mass ratio and the fact that the donor is not dominating the near-infrared emission are all clues of a post bounce system. Although it is possible that QZ Lib could have formed as a white dwarf plus a brown dwarf binary, binary population synthesis studies clearly suggest this scenario to be less likely than a period bouncer detection and we conclude that QZ Lib is a CV that has already evolved through the period minimum.

arXiv comment14 pages, 14 figures. Published in MNRAS

References in corpus (38)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• First Results from the Catalina Real-time Transient Survey
• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• Models of Stars, Brown Dwarfs and Exoplanets
• 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
• Galactic Reddening in 3D from Stellar Photometry - An Improved Map
• The Donor Stars of Cataclysmic Variables
• A Spectroscopic Survey & Analysis of Bright, Hydrogen-Rich White Dwarfs
• An Exploration of the Paradigm for the 2-3 Hour Period Gap in Cataclysmic Variables
• 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
• Superhumps in Cataclysmic Binaries. XXV. q_crit, epsilon(q), and Mass-Radius
• Brown Dwarfs and the Cataclysmic Variable Period Minimum
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae
• Cataclysmic Variables from SDSS II. The Second Year
• Cataclysmic Variables from SDSS I. The First Results
• Measuring White Dwarf Accretion Rates via their Effective Temperatures
• Population Synthesis of Cataclysmic Variables: I. Inclusion of Detailed Nuclear Evolution
• WZ Sge-Type Dwarf Novae
• Effective Temperatures of Cataclysmic Variable White Dwarfs as a Probe of their Evolution
• Cataclysmic Variables from SDSS. VIII. The Final Year (2007-2008)
• A brown dwarf mass donor in an accreting binary
• New Method to Estimate Binary Mass Ratios by Using Superhumps
• Evolution of Cataclysmic Variables and Related Binaries Containing a White-Dwarf
• Cataclysmic Variables from SDSS VII. The Seventh Year (2006)
• The Formation of Cataclysmic Variables with Brown Dwarf Secondaries
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VII: The Seventh Year (2014-2015)
• Pulsations, Boundary Layers, and Period Bounce in the Cataclysmic Variable RE J1255+266
• First Spitzer Space Telescope Observations of Magnetic Cataclysmic Variables: Evidence for Excess Emission at 3--8 microns
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. VIII: The Eighth Year (2015-2016)
• Spitzer Space Telescope observations of magnetic cataclysmic variables: possibilities for the presence of dust in polars
• SDSS J105754.25+275947.5: a period-bounce eclipsing cataclysmic variable with the lowest-mass donor yet measured
• GD 552: a cataclysmic variable with a brown dwarf companion?
• "Dark Matter" in Accretion Disks
• The remarkable outburst of the highly evolved post-period-minimum dwarf nova SSS J122221.7-311525
• An atlas of line profile studies for SU UMa type cataclysmic variables

Cited by in corpus (21)

• 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
• A catalogue of cataclysmic variables from 20 years of the Sloan Digital Sky Survey with new classifications, periods, trends and oddities
• A Catalogue of Potential Post Common Envelope Binaries
• Towards a volumetric census of close white dwarf binaries I.Reference samples
• Galactic Model Parameters and Space Density of Cataclysmic Variables in Gaia Era: New Constraints to Population Models
• Period bouncers as detached magnetic cataclysmic variables
• Nova-produced Common Envelope: Source of the Non-solar Abundances and an Additional Frictional Angular Momentum Loss in Cataclysmic Variables
• A brown dwarf donor and an optically thin accretion disc with a complex stream impact region in the period-bouncer candidate BW Sculptoris
• Hydrodynamics and survivability during post-main-sequence planetary engulfment
• Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. X: The Tenth Year (2017)
• New X-ray detections of magnetic period-bounce cataclysmic variables from XMM-Newton and SRG/eROSITA
• Cataclysmic variables around the period-bounce: An eROSITA-enhanced multi-wavelength catalog
• Spectroscopic Studies of 30 Short-period Cataclysmic Variable Stars, and Remarks on the Evolution and Population of Similar Objects
• Cyclotron emitting magnetic white dwarfs in post common envelope binaries discovered with the Zwicky Transient Facility
• Astrophysics with the Laser Interferometer Space Antenna
• GOTO065054+593624: a 8.5 mag amplitude dwarf nova identified in real time via Kilonova Seekers
• Magnetic braking below the cataclysmic variable period gap and the observed dearth of period bouncers
• ZTFJ0038+2030: a long period eclipsing white dwarf and a substellar companion
• eROSITA-selection of new period-bounce Cataclysmic Variables: First follow-up confirmation using TESS and SDSS
• Detectability of continuous gravitational waves from planetary-mass companions orbiting compact stars