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Fast spectrophotometry of WD 1145+017

Izquierdo, Paula ; Rodriguez-Gil, Pablo ; Gänsicke, Boris T. ; Mustill, Alexander J. LU orcid ; Toloza, Odette ; Tremblay, Pier-Emmanuel ; Wyatt, Mark C ; Chote, Paul ; Eggl, Siegfried and Farihi, Jay , et al. (2018) In Monthly Notices of the Royal Astronomical Society 481(1). p.703-714
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... (More)
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. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
minor planets, asteroids: general, planets and satellites: physical evolution, planet-star interactions, planetary systems, white dwarfs, Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics
in
Monthly Notices of the Royal Astronomical Society
volume
481
issue
1
pages
12 pages
publisher
Oxford University Press
external identifiers
  • scopus:85054072312
ISSN
0035-8711
DOI
10.1093/mnras/sty2315
project
A unified picture of white dwarf planetary systems
IMPACT: Comets, asteroids and the habitability of planets
language
English
LU publication?
yes
id
ee985291-2ba8-44e1-9834-7908127d7824
alternative location
https://arxiv.org/abs/1808.07320
date added to LUP
2018-10-05 14:10:34
date last changed
2024-03-18 15:21:33
@article{ee985291-2ba8-44e1-9834-7908127d7824,
  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.}},
  author       = {{Izquierdo, Paula and Rodriguez-Gil, Pablo and Gänsicke, Boris T. and Mustill, Alexander J. and Toloza, Odette and Tremblay, Pier-Emmanuel and Wyatt, Mark C and Chote, Paul and Eggl, Siegfried and Farihi, Jay and Koester, Detlev and Lyra, Wladimir and Manser, Christopher J. and Marsh, Thomas R. and Pallé, Enric and Raddi, Roberto and Veras, Dimitri and Villaver, Eva and Portegies Zwart, Simon}},
  issn         = {{0035-8711}},
  keywords     = {{minor planets; asteroids: general; planets and satellites: physical evolution; planet-star interactions; planetary systems; white dwarfs; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics}},
  language     = {{eng}},
  month        = {{11}},
  number       = {{1}},
  pages        = {{703--714}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{Fast spectrophotometry of WD 1145+017}},
  url          = {{http://dx.doi.org/10.1093/mnras/sty2315}},
  doi          = {{10.1093/mnras/sty2315}},
  volume       = {{481}},
  year         = {{2018}},
}