Redfield, S;
Farihi, J;
Cauley, PW;
Parsons, SG;
Gaensicke, BT;
Duvvuri, GM;
(2017)
Spectroscopic Evolution of Disintegrating Planetesimals: Minute. to Month. Variability in the Circumstellar Gas Associated with WD 1145+017.
The Astrophysical Journal
, 839
(1)
10.3847/1538-4357/aa68a0.
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Abstract
With the recent discovery of transiting planetary material around WD 1145+017, a critical target has been identified that links the evolution of planetary systems with debris disks and their accretion onto the star. We present a series of observations, five epochs over a year, taken with Keck and the VLT, which for the first time show variability of circumstellar absorption in the gas disk surrounding WD 1145+017 on timescales of minutes to months. Circumstellar absorption is measured in more than 250 lines of 14 ions among 10 different elements associated with planetary composition, e.g., O, Mg, Ca, Ti, Cr, Mn, Fe, and Ni. Broad circumstellar gas absorption with a velocity spread of 225 km s−1 is detected, but over the course of a year blueshifted absorption disappears, while redshifted absorption systematically increases. A correlation of equivalent width and oscillator strength indicates that the gas is not highly optically thick (median τ ≈ 2). We discuss simple models of an eccentric disk coupled with magnetospheric accretion to explain the basic observed characteristics of these high-resolution and high signal-to-noise observations. Variability is detected on timescales of minutes in the two most recent observations, showing a loss of redshifted absorption for tens of minutes, coincident with major transit events and consistent with gas hidden behind opaque transiting material. This system currently presents a unique opportunity to learn how the gas causing the spectroscopic, circumstellar absorption is associated with the ongoing accretion evidenced by photospheric contamination, as well as the transiting planetary material detected in photometric observations.
| Type: | Article |
|---|---|
| Title: | Spectroscopic Evolution of Disintegrating Planetesimals: Minute. to Month. Variability in the Circumstellar Gas Associated with WD 1145+017 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/aa68a0 |
| Publisher version: | http://dx.doi.org/10.3847/1538-4357/aa68a0 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Astronomy & Astrophysics, circumstellar matter, line: profiles, minor planets, asteroids: general, stars: abundances, stars: individual (WD 1145+017), white dwarfs, POLLUTED WHITE-DWARF, EXTRASOLAR MINOR PLANET, T-TAURI STARS, INTERSTELLAR-MEDIUM, DEBRIS DISC, ACCRETION, DISCOVERY, LINE, G29-38, LAMBDA-10830 |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1556212 |
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