WASP-4b

Last updated
WASP-4b
Exoplanet Comparison WASP-4 b.png
Size comparison of WASP-4b with Jupiter.
Discovery [1]
Discovered by Wide Angle Search for Planets
Discovery site South African Astronomical Observatory
Discovery dateOctober 31, 2007
Transit photometry
Orbital characteristics [2]
0.02239±0.00084  AU
Eccentricity <0.0033 [3]
1.338231587(22)  d
Inclination 88.02°±0.69°
Semi-amplitude 232.7+2.5
−2.2  m/s [3]
Star WASP-4
Physical characteristics [2]
1.312±0.045  RJ
Mass 1.164±0.082  MJ
Mean density
0.639±0.079  g/cm3
Temperature 1957±68  K (1,684 °C; 3,063 °F) [4]

    WASP-4b is an exoplanet, specifically a hot Jupiter, approximately 891 light-years away [5] in the constellation of Phoenix. [6]

    Contents

    Discovery

    The planet was the discovered by the Wide Angle Search for Planets team using images taken with the SuperWASP-South project's eight wide-angle cameras located at the South African Astronomical Observatory. [7] [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. WASP-4 b rv.pdf
    The radial velocity trend of WASP-4, caused by the presence of WASP-4 b.

    Characteristics

    The planetary equilibrium temperature would be 1650±30 K, [9] but the measured dayside temperature is higher, with a 2015 study finding 1900±100 K [10] and a 2020 study finding 1957±68 K. [4]

    A study in 2012, utilizing the Rossiter–McLaughlin effect, determined the planetary orbit is probably aligned with the equatorial plane of the star, with misalignment equal to -1+14
    −12    °. [11]

    The planet's orbital period appears to be decreasing at a rate of 7.33±0.71 milliseconds per year, suggesting that its orbit is decaying with a decay timescale of 15.77±1.57 million years. The anomalously high rate of orbital decay of WASP-4b was poorly understood as of 2021. [2] The orbital decay was confirmed in 2025. It is primarily driven by tidal interactions between the planet and its host star. [12]


    References

    1. 1 2 3 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. 1 2 3 Turner, Jake D.; Flagg, Laura; Ridden-Harper, Andrew; Jayawardhana, Ray (2022), "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", The Astronomical Journal, 163 (6): 281, arXiv: 2112.09621 , Bibcode:2022AJ....163..281T, doi: 10.3847/1538-3881/ac686f , S2CID   245329747
    3. 1 2 Bonomo, A. S.; Desidera, S.; et al. (June 2017). "The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets". Astronomy & Astrophysics . 602: A107. arXiv: 1704.00373 . Bibcode:2017A&A...602A.107B. doi:10.1051/0004-6361/201629882. S2CID   118923163.
    4. 1 2 Wong, Ian; Shporer, Avi; Daylan, Tansu; Benneke, Björn; Fetherolf, Tara; Kane, Stephen R.; Ricker, George R.; Vanderspek, Roland; Latham, David W.; Winn, Joshua N.; Jenkins, Jon M.; Boyd, Patricia T.; Glidden, Ana; Goeke, Robert F.; Sha, Lizhou; Ting, Eric B.; Yahalomi, Daniel (2020), "Systematic Phase Curve Study of Known Transiting Systems from Year One of the TESS Mission", The Astronomical Journal, 160 (4): 155, arXiv: 2003.06407 , Bibcode:2020AJ....160..155W, doi: 10.3847/1538-3881/ababad , S2CID   212717799
    5. ↑ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 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. ↑ "Astronomer discovers new planets". BBC News. 2007-10-31. Retrieved 2018-09-23.
    9. ↑ Table 3, Improved parameters for the transiting hot Jupiters WASP-4b and WASP-5b, M. Gillon et al., Astronomy and Astrophysics496, #1 (2009), pp. 259–267, doi:10.1051/0004-6361:200810929, Bibcode:2009A&A...496..259G.
    10. ↑ 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 .
    11. ↑ Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian B.; Hirano, Teruyuki; Bakos, Gaspar; Hartman, Joel D. (2012), "Obliquities of Hot Jupiter Host Stars: Evidence for Tidal Interactions and Primordial Misalignments", The Astrophysical Journal, 757 (1): 18, arXiv: 1206.6105 , Bibcode:2012ApJ...757...18A, doi:10.1088/0004-637X/757/1/18, S2CID   17174530
    12. ↑ Baştürk, Ö; Kutluay, A. C.; Barker, A.; Yalçınkaya, S.; Southworth, J.; Barkaoui, K.; Wünsche, A.; Burgdorf, M. J.; Timmermans, M. (2025-06-17). "The Orbit of WASP-4 b is in Decay". Monthly Notices of the Royal Astronomical Society . arXiv: 2506.15022 . doi: 10.1093/mnras/staf1009 .

    Further reading

    Commons-logo.svg Media related to WASP-4b at Wikimedia Commons

    This page is based on this Wikipedia article
    Text is available under the CC BY-SA 4.0 license; additional terms may apply.
    Images, videos and audio are available under their respective licenses.