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# The space density of post-period minimum cataclysmic variables

Hernandez Santisteban, J.V., Knigge, C., Pretorius, M.L., Sullivan, M. and Warner, B. (2018) The space density of post-period minimum cataclysmic variables. Monthly Notices of the Royal Astronomical Society, 473 (3), 3241–3250.

Record type: Article

## Abstract

Binary evolution theory predicts that accreting white dwarfs with sub-stellar companions dominate the Galactic population of cataclysmic variables (CVs). In order to test these predictions, it is necessary to identify these systems, which may be difficult if the signatures of accretion become too weak to be detected. The only chance to identify such "dead" CVs is by exploiting their close binary nature. We have therefore searched the Sloan Digital Sky Survey (SDSS) Stripe 82 area for apparently isolated white dwarfs that undergo eclipses by a dark companion. We found no such eclipses in either the SDSS or Palomar Transient Factory data sets among our sample of 2264 photometrically selected white dwarf candidates within Stripe 82. This null result allows us to set a firm upper limit on the space density, $\rho_0$, of dead CVs. In order to determine this limit, we have used Monte-Carlo simulations to fold our selection criteria through a simple model of the Galactic CV distribution. Assuming a $T_{WD}=7,500$ K, the resulting 2$\sigma$ limit on the space density of dead CVs is $\rho_0 \lesssim 2 \times 10^{-5}$ pc$^{-3}$, where $T_{WD}$ is the typical effective temperature of the white dwarf in such systems.

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pdf - Accepted Manuscript

Accepted/In Press date: 31 August 2017
e-pub ahead of print date: 9 September 2017
Published date: 21 January 2018
Additional Information: 10 pages, 9 figures, accepted in MNRAS
Keywords: astro-ph.SR

## Identifiers

Local EPrints ID: 414357
URI: https://eprints.soton.ac.uk/id/eprint/414357
ISSN: 0035-8711
ORCID for M. Sullivan: orcid.org/0000-0001-9053-4820

## Catalogue record

Date deposited: 27 Sep 2017 16:30

## Contributors

Author: J.V. Hernandez Santisteban
Author: C. Knigge
Author: M.L. Pretorius
Author: M. Sullivan
Author: B. Warner