Detection limits for close eclipsing and transiting substellar and planetary companions to white dwarfs in the WASP survey Sub-stellar and planetary companions to WDs
Detection limits for close eclipsing and transiting substellar and planetary companions to white dwarfs in the WASP survey Sub-stellar and planetary companions to WDs
复制标题
WASP 巡天中对白矮星近距离食和凌日的次恒星和行星伴星的探测极限 WD 的次恒星和行星伴星
DOI：
10.1111/j.1365-2966.2010.17488.x
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发表时间：
2011
影响因子：
4.8
通讯作者：
Faedi F
中科院分区：
文献类型：
--
作者：
Faedi F
We have performed extensive simulations to explore the possibility of detecting eclipses and transits of close, substellar and planetary companions to white dwarfs in WASP (the UK Wide-Angle Search for Planets) light curves. Our simulations cover companions∼ 0.3< R pl< 12 R and orbital periods 2< P< 15 d, equivalent to orbital radii 0.003< a< 0.1 au. For Gaussian random noise, WASP is sensitive to transits by companions as small as the Moon orbiting a V≃ 12 white dwarf. For fainter white dwarfs, WASP is sensitive to increasingly larger radius bodies. However, in the presence of correlated noise structure in the light curves, the sensitivity drops, although Earth-sized companions remain detectable, in principle, even in low signal-to-noise data. Mars-sized, and even Mercury-sized, bodies yield reasonable detection rates in high-quality light curves with little residual noise. We searched for eclipses and transit signals in long-term light curves of a sample of 194 white dwarfs resulting from a cross-correlation of the McCook & Sion catalogue and the WASP archive. No evidence for eclipsing or transiting substellar and planetary companions was found. We used this non-detection and results from our simulations to place tentative upper limits to the frequency of such objects in close orbits at white dwarfs. While only weak limits can be placed on the likely frequency of Earth-sized or smaller companions, brown dwarfs and gas giants (radius≈ R jup) with periods< 0.1–0.2 d must certainly be rare (< 10 per cent). More stringent constraints likely require significantly larger white dwarf samples, higher observing cadence and continuous coverage. The short duration of eclipses and transits of white dwarfs compared to the cadence of WASP observations appears to be one of the main factors limiting the detection rate in a survey optimized for planetary transits of main-sequence stars.
