WASP-4b

WASP-4b is an extrasolar planet approximately 891 light-years away[5] in the constellation of Phoenix.[6]

WASP-4b
Size comparison of WASP-4b with Jupiter.
Discovery[1][2]
Discovered byWide Angle Search for Planets
Discovery siteSouth African Astronomical Observatory
Discovery dateOctober 31, 2007
Transit photometry
Orbital characteristics
0.02255+0.00095
−0.00065[3] AU
Eccentricity0.0[3]
1.3382324+0.0000017
−0.0000029[3] d
Inclination89.35+0.64
−0.49[3]
Semi-amplitude247.6+13.9
−6.8[3]
StarWASP-4
Physical characteristics
Mean radius
1.304+0.054
−0.042[3] RJ
Mass1.21+0.13
−0.08[3] MJ
Temperature1900±100[4]

    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.[7][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.[4] Dayside temperature measured in 2020 is 1957±68 K.[8]

    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    °.[9]

    References
    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.
    2. "Astronomer discovers new planets". BBC News. 2007-10-31. Retrieved 2018-09-23.
    3. 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.
    4. 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.
    5. Brown, A. G. A.; et al. (Gaia collaboration). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics (in press). arXiv:2012.01533. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
    6. 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
    7. Sherriff, Lucy (2007-10-31). "UK boffins ID three new exo-planets". The Register. Retrieved 2018-09-23.
    8. Systematic phase curve study of known transiting systems from year one of the TESS mission, 2020, arXiv:2003.06407
    9. Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments, 2012, arXiv:1206.6105

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