Fast spectrophotometry of WD 1145+017

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

WD 1145+017 is currently the only white dwarf known to exhibit periodic transits of planetary debris as well as absorption lines from circumstellar gas. We present the first simultaneous fast optical spectrophotometry and broad-band photometry of the system, obtained with the Gran Telescopio Canarias (GTC) and the Liverpool Telescope, respectively. The observations spanned 5.5 h, somewhat longer than the 4.5-h orbital period of the debris. Dividing the GTC spectrophotometry into five wavelength bands reveals no significant colour differences, confirming grey transits in the optical. We argue that absorption by an optically thick structure is a plausible alternative explanation for the achromatic nature of the transits that can allow the presence of small-sized (~µm) particles. The longest (87 min) and deepest (50 per cent attenuation) transit recorded in our data exhibits a complex structure around minimum light that can be well modelled by multiple overlapping dust clouds. The strongest circumstellar absorption line, Fe II λ5169, significantly weakens during this transit, with its equivalent width reducing from a mean out-of-transit value of 2 to 1 Å in-transit, supporting spatial correlation between the circumstellar gas and dust. Finally, we made use of the Gaia Data Release 2 and archival photometry to determine the white dwarf parameters. Adopting a helium-dominated atmosphere containing traces of hydrogen and metals, and a reddening E(B - V) = 0.01 we find T_eff=15 020 ± 520 K, log g = 8.07 ± 0.07, corresponding to M_WD=0.63± 0.05 M☉ and a cooling age of 224 ± 30 Myr.

Detaljer

Författare
  • Paula Izquierdo
  • Pablo Rodriguez-Gil
  • Boris T. Gänsicke
  • Alexander J. Mustill
  • Odette Toloza
  • Pier-Emmanuel Tremblay
  • Mark C Wyatt
  • Paul Chote
  • Siegfried Eggl
  • Jay Farihi
  • Detlev Koester
  • Wladimir Lyra
  • Christopher J. Manser
  • Thomas R. Marsh
  • Enric Pallé
  • Roberto Raddi
  • Dimitri Veras
  • Eva Villaver
  • Simon Portegies Zwart
Enheter & grupper
Externa organisationer
  • University of La Laguna (ULL)
  • Instituto de Astrofísica de Canarias
  • University of Warwick
  • University of Cambridge
  • California Institute of Technology
  • University College London
  • University of Kiel
  • California State University Northridge
  • Friedrich-Alexander University Erlangen-Nürnberg
  • Autonomous University of Madrid
  • Leiden University
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Astronomi, astrofysik och kosmologi

Nyckelord

Originalspråkengelska
Sidor (från-till)703-714
Antal sidor12
TidskriftMonthly Notices of the Royal Astronomical Society
Volym481
Utgivningsnummer1
StatusPublished - 2018 nov 21
PublikationskategoriForskning
Peer review utfördJa

Related projects

Alex Mustill

Swedish Research Council

2018/01/012022/12/31

Projekt: Forskning

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