WASP-4b

WASP-4b is an extrasolar planet approximately 880 light-years away in the constellation of Phoenix.

WASP-4b
Size comparison of WASP-4b with Jupiter.
Discovery
Discovered byDavid. M. Wilson et al. (SuperWASP)[1]
Discovery siteSAAO
Discovery dateOctober 31, 2007[2]
Transit
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]

    The planet was the discovered by the SuperWASP project using cameras in South Africa.[5] After its discovery, the mass of the WASP-4 b was determined by measuring the radial velocity of WASP-4, which confirmed that the object that caused the transit was a planet.[1]

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

    The equilibrium planetary temperature would be 1650±30 K,[3] but measured temperature is higher at 1900±100 K.[4]

    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    °.[6]

    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. Sherriff, Lucy (2007-10-31). "UK boffins ID three new exo-planets". The Register. Retrieved 2018-09-23.
    6. Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments, 2012, arXiv:1206.6105

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