Full-text links:
Download:
- PostScript
- Other formats
Current browse context:
astro-ph.EP
< prev | next >
new | recent | 0908
Change to browse by:
astro-ph
References & Citations
- NASA ADS
Bookmark
(what is this?)Astrophysics > Earth and Planetary Astrophysics
Title: WASP-17b: an ultra-low density planet in a probable retrograde orbit
Authors:
D. R. Anderson,
C. Hellier,
M. Gillon,
A. H. M. J. Triaud,
B. Smalley,
L. Hebb,
A. Collier Cameron,
P. F. L. Maxted,
D. Queloz,
R. G. West,
S. J. Bentley,
B. Enoch,
K. Horne,
T. A. Lister,
M. Mayor,
N. R. Parley,
F. Pepe,
D. Pollacco,
D. Ségransan,
S. Udry,
D. M. Wilson
(Submitted on 11 Aug 2009 (v1), last revised 25 Nov 2009 (this version, v2))
Abstract: We report the discovery of the transiting giant planet WASP-17b, the least-dense planet currently known. It is 1.6 Saturn masses but 1.5-2 Jupiter radii, giving a density of 6-14 per cent that of Jupiter. WASP-17b is in a 3.7-day orbit around a sub-solar metallicity, V = 11.6, F6 star. Preliminary detection of the Rossiter-McLaughlin effect suggests that WASP-17b is in a retrograde orbit (lambda ~ -150 deg), indicative of a violent history involving planet-planet or star-planet scattering.
WASP-17b's bloated radius could be due to tidal heating resulting from recent or ongoing tidal circularisation of an eccentric orbit, such as the highly eccentric orbits that typically result from scattering interactions. It will thus be important to determine more precisely the current orbital eccentricity by further high-precision radial velocity measurements or by timing the secondary eclipse, both to reduce the uncertainty on the planet's radius and to test tidal-heating models. Owing to its low surface gravity, WASP-17b's atmosphere has the largest scale height of any known planet, making it a good target for transmission spectroscopy.
Comments: | 9 pages, 7 figures, 5 tables, accepted for publication in ApJ |
Subjects: | Earth and Planetary Astrophysics (astro-ph.EP) |
Cite as: | arXiv:0908.1553 [astro-ph.EP] |
(or arXiv:0908.1553v2 [astro-ph.EP] for this version) |
Submission history
From: David Anderson [view email][v1] Tue, 11 Aug 2009 18:47:05 GMT (125kb)
[v2] Wed, 25 Nov 2009 20:06:13 GMT (127kb)
Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)