WASP-17b
Discovery[1] | |
---|---|
Discovered by | David R. Anderson et al |
Discovery date | 11 August 2009 |
Transit (including secondary eclipse) | |
Orbital characteristics[2] | |
0.05151±0.00035 AU | |
Eccentricity | <0.020 |
3.7354845±0.0000019 d | |
Inclination | 86.83°+0.68° −0.53° |
−70[citation needed] | |
Semi-amplitude | 56.0+4.1 −4.0 m/s |
Star | WASP-17 |
Physical characteristics[2] | |
Mean radius | 1.991±0.081 RJ |
Mass | 0.512±0.037 MJ |
Mean density | 0.080+0.013 −0.011 g/cm3 |
Temperature | 1,550+170 −200 K[3] |
WASP-17b is an
WASP-17b is named Ditsö̀. The name was selected in the NameExoWorlds campaign by Costa Rica, during the 100th anniversary of the International Astronomical Union. Ditsö̀ is the name that the god Sibö̀ gave to the first Bribri people in Talamancan mythology.[8][9]
Discovery
A team of researchers led by David Anderson of Keele University in Staffordshire, England, discovered the gas giant, which is about 1,000 light-years (310 parsecs) from Earth, by observing it transiting its host star WASP-17. Such photometric observations also reveal the planet's size. The discovery was made with a telescope array at the South African Astronomical Observatory. Due to the involvement of the Wide Angle Search for Planets SuperWASP consortium of universities, the exoplanet, as the 17th found to date by this group, was given its present name.[10]
Astronomers at the
Orbit
WASP-17b is thought to have a
−6.7°.[13]
Physical properties
WASP-17b has a radius between 1.5 and 2 times that of Jupiter and about half the mass.[1] Thus its mean density is between 0.08 and 0.19 g/cm3,[1] compared with Jupiter's 1.326 g/cm3[14] and Earth's 5.515 g/cm3 (the density of water is 1 g/cm3). The unusually low density is thought to be a consequence of a combination of the planet's orbital eccentricity and its proximity to its parent star (less than one seventh of the distance between Mercury and the Sun), leading to tidal flexing and heating of its interior.[1] The same mechanism is behind the intense volcanic activity of Jupiter's moon Io. WASP-39b has a similarly low estimated density.
Exoplanetary sodium in the atmosphere of the WASP-17 has been detected in 2018,[3] but was not confirmed by 2021. Instead, the spectral signatures of water, aluminium oxide (AlO) and titanium hydride (TiH) were detected.[15] The water signature was confirmed in 2022, together with carbon dioxide absorption.[16] In 2023, evidence of clouds made of quartz was detected on the planet by the James Webb Space Telescope.[17][18]
See also
- HAT-P-7b, another exoplanet announced to have a retrograde orbit the day after the WASP-17b announcement
- TrES-4b, another large exoplanet with a low density
- List of exoplanet extremes
References
- ^ S2CID 53628741.
- ^ S2CID 118923163.
- ^ S2CID 119007114.
- ^ "A planet going the wrong way", Phys Org. June 7, 2011. Accessed June 10, 2011
- National Geographic. National Geographic Society. Archived from the originalon August 20, 2009. Retrieved 6 February 2011.
- ^ "Hubble Traces Subtle Signals of Water on Hazy Worlds". NASA. 3 December 2013. Retrieved 4 December 2013.
- S2CID 52997396.
- ^ "Approved names". NameExoworlds. Retrieved 2020-01-02.
- ^ "100 000s of People from 112 Countries Select Names for Exoplanet Systems In Celebration of IAU's 100th Anniversary". International Astronomical Union. Retrieved 2020-01-02.
- ^ Rincon, Paul (August 13, 2009). "New planet displays exotic orbit". BBC News. Retrieved 2009-08-13.
- A&A 2010. arXiv preprint
- ^ Grossman, Lisa (August 13, 2009). "Planet found orbiting its star backwards". New Scientist. Retrieved 2009-08-13.
- S2CID 17174530
- ^ "Jupiter Fact Sheet". Retrieved 2009-08-13.
- S2CID 237363318
- .
- STScI. 16 October 2023. Retrieved 16 October 2023.
- ^ "Composition of cloud particles - hot gas giant exoplanet WASP-17b". October 20, 2023.
External links
Media related to WASP-17b at Wikimedia Commons
- Alexander, Amir. Scientists Detect "Wrong-Way" Planet. [1] Archived 2009-08-16 at the Wayback Machine The Planetary Society, August 12, 2009. Accessed August 14, 2009.