Fast spectrophotometry of WD 1145+017
(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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https://lup.lub.lu.se/record/ee985291-2ba8-44e1-9834-7908127d7824
- author
- organization
- publishing date
- 2018-11-21
- 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}}, }