• DOI:10.1093/mnras/stv282
• Corpus ID: 119196673

The frequency and infrared brightness of circumstellar discs at white dwarfs

@article{Rocchetto2014TheFA,
  title={The frequency and infrared brightness of circumstellar discs at white dwarfs},
  author={Marco Rocchetto and Jay Farihi and Boris T. Gaensicke and Carolina Bergfors},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2014},
  volume={449},
  pages={574-587}
}

• M. Rocchetto, J. Farihi, +1 author C. Bergfors
• Published 23 October 2014
• Physics, Geology
• Monthly Notices of the Royal Astronomical Society

White dwarfs whose atmospheres are polluted by terrestrial-like planetary debris have become a powerful and unique tool to study evolved planetary systems. This paper presents results for an unbiased Spitzer IRAC search for circumstellar dust orbiting a homogeneous and well-dened sample of 134 single white dwarfs. The stars were selected without regard to atmospheric metal content but were chosen to have 1) hydrogen rich atmospheres, 2) 17 000 K < Te < 25 000 K and correspondingly young post main-sequence ages of 15{270 Myr, and 3) sucient far-ultraviolet brightness for a corresponding Hubble Space Telescope COS Snapshot. Five white dwarfs were found to host an infrared bright dust disc, three previously known, and two reported here for the rst time, yielding a nominal 3.7% of white dwarfs in this post-main sequence age range with detectable circumstellar dust. Remarkably, complementary HST observations indicate that a fraction of 27% show metals in their photosphere that can only be explained with ongoing accretion from circumstellar material, indicating that nearly 90% of discs escape detection in the infrared, likely due to small emitting surface area. This paper also presents the distribution of disc fractional luminosity as a function of cooling age for all known dusty white dwarfs, suggesting possible disc evolution scenarios and indicating an undetected population of circumstellar discs.