WASP-4b

WASP-4b
	Size comparison of WASP-4b with Jupiter.
Discovery
Discovered by	Wide Angle Search for Planets
Discovery site	South African Astronomical Observatory
Discovery date	October 31, 2007
Detection method	Transit photometry
Orbital characteristics
Semi-major axis	0.02255+0.00095; −0.00065 AU
Eccentricity	0.0
Orbital period (sidereal)	1.338231587±0.000000022 d
Inclination	89.35+0.64; −0.49
Semi-amplitude	247.6+13.9; −6.8
Star	WASP-4
Physical characteristics
Mean radius	1.304+0.054; −0.042 RJ
Mass	1.21+0.13; −0.08 MJ
Temperature	1900±100

WASP-4b is an extrasolar planet approximately 891 light-years away^[6] in the constellation of Phoenix.^[7]

Discovery[]

The planet was the discovered by the Wide Angle Search for Planets team using images taken with the SuperWASP-South projects eight wide-angle cameras located at the South African Astronomical Observatory.^[8]^[1] Analysis of over 4000 images taken between May and November 2006 resulted in the detection of a transit occurring every 1.3 days. Follow-up radial velocity observations using the Swiss 1.2-metre Leonhard Euler Telescope confirmed that the transiting object was a planet.^[1]

The radial velocity trend of WASP-4, caused by the presence of WASP-4 b.

Characteristics[]

The equilibrium planetary temperature would be 1650±30 K,^[3] but measured temperature is higher at 1900±100 K.^[5] Dayside temperature measured in 2020 is 1957±68 K.^[9]

The study in 2012, utilizing a Rossiter–McLaughlin effect, have determined the planetary orbit is probably aligned with the equatorial plane of the star, misalignment equal to -1⁺¹⁴
₋₁₂°.^[10]

The orbital period of the planet is decreasing by 7.33±0.71 milliseconds per year, with decay timescale of 15.77±1.57 million years. The anomalously high rate of orbital decay of WASP-4b is poorly understood as in 2021.^[4]

References[]

^ ^a ^b ^c Wilson, D. M.; et al. (2008). "WASP-4b: A 12th Magnitude Transiting Hot Jupiter in the Southern Hemisphere". The Astrophysical Journal Letters. 675 (2): L113–L116. arXiv:0801.1509. Bibcode:2008ApJ...675L.113W. doi:10.1086/586735.
^ "Astronomer discovers new planets". BBC News. 2007-10-31. Retrieved 2018-09-23.
^ ^a ^b ^c ^d ^e ^f ^g Table 3, Improved parameters for the transiting hot Jupiters WASP-4b and WASP-5b, M. Gillon et al., Astronomy and Astrophysics 496, #1 (2009), pp. 259–267, doi:10.1051/0004-6361:200810929, Bibcode:2009A&A...496..259G.
^ ^a ^b Characterizing the WASP-4 system with TESS and radial velocity data: Constraints on the cause of the hot Jupiter’s changing orbit and evidence of an outer planet, 2021, arXiv:2112.09621
^ ^a ^b Zhou, G.; Bayliss, D. D. R.; Kedziora-Chudczer, L.; Tinney, C. G.; Bailey, J.; Salter, G.; Rodriguez, J. (2015). "Secondary eclipse observations for seven hot-Jupiters from the Anglo-Australian Telescope". Monthly Notices of the Royal Astronomical Society. 454 (3): 3002–3019. arXiv:1509.04147. Bibcode:2015MNRAS.454.3002Z. doi:10.1093/mnras/stv2138.
^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
^ Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
^ Sherriff, Lucy (2007-10-31). "UK boffins ID three new exo-planets". The Register. Retrieved 2018-09-23.
^ Systematic phase curve study of known transiting systems from year one of the TESS mission, 2020, arXiv:2003.06407
^ Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments, 2012, arXiv:1206.6105

External links[]

Media related to WASP-4b at Wikimedia Commons

"Transiting exoplanets from the Wide Angle Search for Planets". WASP Planets. Coel Hellier. Retrieved 2020-12-27.
"UK planet hunters announce three new finds" (PDF). 2007-10-30. Archived from the original (PDF) on 2008-05-16. Retrieved 2008-07-02.

Coordinates: 23^h 34^m 15.06^s, −42° 03′ 41.1″

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[Wilson2008-1] Wilson, D. M.; et al. (2008). "WASP-4b: A 12th Magnitude Transiting Hot Jupiter in the Southern Hemisphere". The Astrophysical Journal Letters. 675 (2): L113–L116. arXiv:0801.1509. Bibcode:2008ApJ...675L.113W. doi:10.1086/586735.

[BBC_News-2] "Astronomer discovers new planets". BBC News. 2007-10-31. Retrieved 2018-09-23.

[wasp2-3] ^ ^a ^b ^c ^d ^e ^f ^g Table 3, Improved parameters for the transiting hot Jupiters WASP-4b and WASP-5b, M. Gillon et al., Astronomy and Astrophysics 496, #1 (2009), pp. 259–267, doi:10.1051/0004-6361:200810929, Bibcode:2009A&A...496..259G.

[Turner2021-4] Characterizing the WASP-4 system with TESS and radial velocity data: Constraints on the cause of the hot Jupiter’s changing orbit and evidence of an outer planet, 2021, arXiv:2112.09621

[Zhou2015-5] Zhou, G.; Bayliss, D. D. R.; Kedziora-Chudczer, L.; Tinney, C. G.; Bailey, J.; Salter, G.; Rodriguez, J. (2015). "Secondary eclipse observations for seven hot-Jupiters from the Anglo-Australian Telescope". Monthly Notices of the Royal Astronomical Society. 454 (3): 3002–3019. arXiv:1509.04147. Bibcode:2015MNRAS.454.3002Z. doi:10.1093/mnras/stv2138.

[Gaia_EDR3-6] Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.

[Roman1987-7] Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form

[The_Register-8] Sherriff, Lucy (2007-10-31). "UK boffins ID three new exo-planets". The Register. Retrieved 2018-09-23.

[Wong2020-9] Systematic phase curve study of known transiting systems from year one of the TESS mission, 2020, arXiv:2003.06407

[10] Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments, 2012, arXiv:1206.6105

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