Clayton, GC;
Sugerman, BEK;
Stanford, SA;
Whitney, BA;
Honor, J;
Babler, B;
Barlow, MJ;
... Lim, TL; + view all
(2011)
The circumstellar environment of R Coronae Borealis: white dwarf merger or final-helium-shell flash?
The Astrophysical Journal
, 743
(1)
, Article 44. 10.1088/0004-637X/743/1/44.
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Abstract
In 2007, R Coronae Borealis (R CrB) went into a historically deep and long decline. In this state, the dust acts like a natural coronagraph at visible wavelengths, allowing faint nebulosity around the star to be seen. Imaging has been obtained from 0.5 to 500 μm with Gemini/GMOS, Hubble Space Telescope/WFPC2, Spitzer/MIPS, and Herschel/SPIRE. Several of the structures around R CrB are cometary globules caused by wind from the star streaming past dense blobs. The estimated dust mass of the knots is consistent with their being responsible for the R CrB declines if they form along the line of sight to the star. In addition, there is a large diffuse shell extending up to 4 pc away from the star containing cool 25 K dust that is detected all the way out to 500 μm. The spectral energy distribution of R CrB can be well fitted by a 150 AU disk surrounded by a very large diffuse envelope which corresponds to the size of the observed nebulosity. The total masses of the disk and envelope are 10–4 and 2 M ☉, respectively, assuming a gas-to-dust ratio of 100. The evidence pointing toward a white dwarf merger or a final-helium-shell flash origin for R CrB is contradictory. The shell and the cometary knots are consistent with a fossil planetary nebula. Along with the fact that R CrB shows significant lithium in its atmosphere, this supports the final-helium-shell flash. However, the relatively high inferred mass of R CrB and its high fluorine abundance support a white dwarf merger.
| Type: | Article |
|---|---|
| Title: | The circumstellar environment of R Coronae Borealis: white dwarf merger or final-helium-shell flash? |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1088/0004-637X/743/1/44 |
| Publisher version: | https://doi.org/10.1088/0004-637X/743/1/44 |
| 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: | dust, extinction; stars: evolution; stars: mass-loss |
| 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/10097369 |
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