The Library
Long-term eclipse timing of white dwarf binaries : an observational hint of a magnetic mechanism at work
Tools
(2016) Long-term eclipse timing of white dwarf binaries : an observational hint of a magnetic mechanism at work. Monthly Notices of the Royal Astronomical Society, 460 (4). pp. 3873-3887. doi:10.1093/mnras/stw1203 ISSN 0035-8711.
PDF
WRAP_MNRAS-2016-Bours-3873-87.pdf - Published Version - Requires a PDF viewer. Download (2199Kb) |
Official URL: http://dx.doi.org/10.1093/mnras/stw1203
Abstract
We present a long-term programme for timing the eclipses of white dwarfs in close binaries to measure apparent and/or real variations in their orbital periods. Our programme includes 67 close binaries, both detached and semi-detached and with M-dwarfs, K-dwarfs, brown dwarfs or white dwarfs secondaries. In total, we have observed more than 650 white dwarf eclipses. We use this sample to search for orbital period variations and aim to identify the underlying cause of these variations. We find that the probability of observing orbital period variations increases significantly with the observational baseline. In particular, all binaries with baselines exceeding 10 yr, with secondaries of spectral type K2 – M5.5, show variations in the eclipse arrival times that in most cases amount to several minutes. In addition, among those with baselines shorter than 10 yr, binaries with late spectral type (>M6), brown dwarf or white dwarf secondaries appear to show no orbital period variations. This is in agreement with the so-called Applegate mechanism, which proposes that magnetic cycles in the secondary stars can drive variability in the binary orbits. We also present new eclipse times of NN Ser, which are still compatible with the previously published circumbinary planetary system model, although only with the addition of a quadratic term to the ephemeris. Finally, we conclude that we are limited by the relatively short observational baseline for many of the binaries in the eclipse timing programme, and therefore cannot yet draw robust conclusions about the cause of orbital period variations in evolved, white dwarf binaries.
Item Type: | Journal Article | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Subjects: | Q Science > QB Astronomy | ||||||||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | ||||||||||
Library of Congress Subject Headings (LCSH): | White dwarf stars, Eclipses | ||||||||||
Journal or Publication Title: | Monthly Notices of the Royal Astronomical Society | ||||||||||
Publisher: | Oxford University Press | ||||||||||
ISSN: | 0035-8711 | ||||||||||
Official Date: | 21 August 2016 | ||||||||||
Dates: |
|
||||||||||
Volume: | 460 | ||||||||||
Number: | 4 | ||||||||||
Page Range: | pp. 3873-3887 | ||||||||||
DOI: | 10.1093/mnras/stw1203 | ||||||||||
Status: | Peer Reviewed | ||||||||||
Publication Status: | Published | ||||||||||
Access rights to Published version: | Open Access (Creative Commons) | ||||||||||
Date of first compliant deposit: | 23 August 2016 | ||||||||||
Date of first compliant Open Access: | 23 August 2016 | ||||||||||
Funder: | European Southern Observatory (ESO), Chile. Chilean Government, Science and Technology Facilities Council (Great Britain) (STFC), Chile. Comisión Nacional de Investigación Científica y Tecnológica (CONICYT), Chile. Ministerio de Economía, United States. National Aeronautics and Space Administration (NASA), National Research Foundation (South Africa) (NRF), European Research Council (ERC) | ||||||||||
Grant number: | ST/L000733, ST/L00075X/1 and ST/M001350/1 (STFC), 3140585 and 3140592 (CONICYT), Millennium Nucleus RC130007 (Ministerio de Economía), HST-HF2-51357.001-A, NAS5-26555 (NASA), Grant no. 320964 (ERC) |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |
Downloads
Downloads per month over past year