WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT

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. Segransan; S. Udry; D. M. Wilson

doi:10.1088/0004-637X/709/1/159

WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT

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. Segransan, S. UdryD. M. Wilson

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

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% 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 approximate to -150 degrees), 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 circularization 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.

Original language	English
Pages (from-to)	159-167
Number of pages	9
Journal	Astrophysical Journal Letters
Volume	709
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/709/1/159
Publication status	Published - 20 Jan 2010

Keywords

planetary systems
stars: individual (WASP-17)
TRANSITING EXTRASOLAR PLANETS
LIGHT-CURVE PROJECT
SPIN-ORBIT
GIANT PLANETS
IMPROVED PARAMETERS
EXOPLANET HAT-P-1B
TIDAL INFLATION
ECCENTRIC ORBIT
HOT JUPITERS
SYSTEM

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10.1088/0004-637X/709/1/159

Cite this

Anderson, D. R., Hellier, C., Gillon, M., Triaud, A. H. M. J., Smalley, B., Hebb, L., Cameron, A. C., Maxted, P. F. L., Queloz, D., West, R. G., Bentley, S. J., Enoch, B., Horne, K., Lister, T. A., Mayor, M., Parley, N. R., Pepe, F., Pollacco, D., Segransan, D., ... Wilson, D. M. (2010). WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT. Astrophysical Journal Letters, 709(1), 159-167. https://doi.org/10.1088/0004-637X/709/1/159

@article{c913dfbddaae4182a3651ff2a5b1d085,

title = "WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT",

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% 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 approximate to -150 degrees), 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 circularization 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.",

keywords = "planetary systems, stars: individual (WASP-17), TRANSITING EXTRASOLAR PLANETS, LIGHT-CURVE PROJECT, SPIN-ORBIT, GIANT PLANETS, IMPROVED PARAMETERS, EXOPLANET HAT-P-1B, TIDAL INFLATION, ECCENTRIC ORBIT, HOT JUPITERS, SYSTEM",

author = "Anderson, {D. R.} and C. Hellier and M. Gillon and Triaud, {A. H. M. J.} and B. Smalley and L. Hebb and Cameron, {A. Collier} and Maxted, {P. F. L.} and D. Queloz and West, {R. G.} and Bentley, {S. J.} and B. Enoch and K. Horne and Lister, {T. A.} and M. Mayor and Parley, {N. R.} and F. Pepe and D. Pollacco and D. Segransan and S. Udry and Wilson, {D. M.}",

year = "2010",

month = jan,

day = "20",

doi = "10.1088/0004-637X/709/1/159",

language = "English",

volume = "709",

pages = "159--167",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

publisher = "American Astronomical Society",

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Anderson, DR, Hellier, C, Gillon, M, Triaud, AHMJ, Smalley, B, Hebb, L, Cameron, AC, Maxted, PFL, Queloz, D, West, RG, Bentley, SJ, Enoch, B, Horne, K, Lister, TA, Mayor, M, Parley, NR, Pepe, F, Pollacco, D, Segransan, D, Udry, S & Wilson, DM 2010, 'WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT', Astrophysical Journal Letters, vol. 709, no. 1, pp. 159-167. https://doi.org/10.1088/0004-637X/709/1/159

TY - JOUR

T1 - WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT

AU - Anderson, D. R.

AU - Hellier, C.

AU - Gillon, M.

AU - Triaud, A. H. M. J.

AU - Smalley, B.

AU - Hebb, L.

AU - Cameron, A. Collier

AU - Maxted, P. F. L.

AU - Queloz, D.

AU - West, R. G.

AU - Bentley, S. J.

AU - Enoch, B.

AU - Horne, K.

AU - Lister, T. A.

AU - Mayor, M.

AU - Parley, N. R.

AU - Pepe, F.

AU - Pollacco, D.

AU - Segransan, D.

AU - Udry, S.

AU - Wilson, D. M.

PY - 2010/1/20

Y1 - 2010/1/20

N2 - 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% 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 approximate to -150 degrees), 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 circularization 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.

AB - 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% 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 approximate to -150 degrees), 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 circularization 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.

KW - planetary systems

KW - stars: individual (WASP-17)

KW - TRANSITING EXTRASOLAR PLANETS

KW - LIGHT-CURVE PROJECT

KW - SPIN-ORBIT

KW - GIANT PLANETS

KW - IMPROVED PARAMETERS

KW - EXOPLANET HAT-P-1B

KW - TIDAL INFLATION

KW - ECCENTRIC ORBIT

KW - HOT JUPITERS

KW - SYSTEM

UR - http://www.scopus.com/inward/record.url?scp=73849143401&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/709/1/159

DO - 10.1088/0004-637X/709/1/159

M3 - Article

SN - 2041-8205

VL - 709

SP - 159

EP - 167

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

ER -

WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT

Abstract

Keywords

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Astrophysics in St Andrews: Astrophysics in St Andrews / SUPA (Continuan of Rolling Grant - XPP089

Wide Area Search for Planets: Project support for the Wide Area Search for Planets

Cite this

WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Projects

Astrophysics in St Andrews: Astrophysics in St Andrews / SUPA (Continuan of Rolling Grant - XPP089

Wide Area Search for Planets: Project support for the Wide Area Search for Planets

Cite this