WASP-78

WASP-78, is a single F-type main-sequence star about 2500 light-years away. It is likely to be younger than the Sun at 3.4+1.5
−0.8 billion years.[4] WASP-78 is depleted in heavy elements, having a 45% concentration of iron compared to the Sun.

WASP-78
Observation data
Epoch J2000      Equinox J2000
Constellation Eridanus
Right ascension 04h 15m 01.5044s[1]
Declination −22° 06′ 59.1039″[1]
Apparent magnitude (V) 12.0[2]
Characteristics
Evolutionary stage main-sequence star
Spectral type F8[2]
Astrometry
Radial velocity (Rv)1.26[1] km/s
Proper motion (μ) RA: -0.463[1] mas/yr
Dec.: 6.424[1] mas/yr
Parallax (π)1.2968 ± 0.0292 mas[3]
Distance2,520 ± 60 ly
(770 ± 20 pc)
Details
Mass1.33±0.09[2] M☉
Radius2.20±0.12[2] R☉
Luminosity5.8±0.2[3] L☉
Surface gravity (log g)3.88±0.04[2] cgs
Temperature6100±150[2] K
Metallicity [Fe/H]-0.35±0.14[2] dex
Rotation0.4±0.4[2]
Rotational velocity (v sin i)6.63±0.16[4] km/s
Age3.4+1.5
−0.8[4] Gyr
Other designations
Gaia DR2 5089851638095503616, TYC 5889-271-1, GSC 05889-00271, 2MASS J04150149-2206591[1]
Database references
SIMBADdata

Planetary system

In 2012 a transiting hot Jupiter planet b was detected on a circular orbit. The planetary equilibrium temperature is 2350±80 K,[2] while the nightside temperature measured in 2019 is 2200±41 K.[5] The dayside planetary temperature measured in 2020 is 2560±130 K.[6]

A survey in 2016 measured a Rossiter-McLaughlin effect and found the planetary orbit is well aligned with the equatorial plane of the star, misalignment equal to −6.4±5.9°[4] The planet cannot have formed in its current orbit and has likely undergone in the past a migration from the initial highly eccentric orbit.[7]

The WASP-78 planetary system[2]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 0.89±0.08 MJ 0.0362±0.0008 2.17517632±0.0000047 0 83.2+2.3
−1.6°		 1.70±0.11 RJ

References
  1. "WASP-78". SIMBAD. Centre de données astronomiques de Strasbourg.
  2. Smalley, B.; Anderson, D. R.; Collier-Cameron, A.; Doyle, A. P.; Fumel, A.; Gillon, M.; Hellier, C.; Jehin, E.; Lendl, M.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Smith, A. M. S.; Southworth, J.; Triaud, A. H. M. J.; Udry, S.; West, R. G. (2012), "WASP-78b and WASP-79b: Two highly-bloated hot Jupiter-mass exoplanets orbiting F-type stars in Eridanus", Astronomy & Astrophysics, 547: A61, arXiv:1206.1177, Bibcode:2012A&A...547A..61S, doi:10.1051/0004-6361/201219731, S2CID 119233646
  3. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  4. Brown, D. J. A.; Triaud, A. H. M. J.; Doyle, A. P.; Gillon, M.; Lendl, M.; Anderson, D. R.; Collier Cameron, A.; Hébrard, G.; Hellier, C.; Lovis, C.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Smalley, B. (2016), "Rossiter–McLaughlin models and their effect on estimates of stellar rotation, illustrated using six WASP systems", Monthly Notices of the Royal Astronomical Society, 464: 810–839, arXiv:1610.00600, doi:10.1093/mnras/stw2316, S2CID 53497449
  5. Garhart, Emily; Deming, Drake; Mandell, Avi; Knutson, Heather A.; Wallack, Nicole; Burrows, Adam; Fortney, Jonathan J.; Hood, Callie; Seay, Christopher; Sing, David K.; Benneke, Björn; Fraine, Jonathan D.; Kataria, Tiffany; Lewis, Nikole; Madhusudhan, Nikku; McCullough, Peter; Stevenson, Kevin B.; Wakeford, Hannah (2020), "Statistical Characterization of Hot Jupiter Atmospheres Using Spitzer's Secondary Eclipses", The Astronomical Journal, 159 (4): 137, arXiv:1901.07040, Bibcode:2020AJ....159..137G, doi:10.3847/1538-3881/ab6cff, S2CID 119209434
  6. 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
  7. Valsecchi, Francesca (2014), "Planets on the Edge", The Astrophysical Journal, 787 (1): L9, arXiv:1403.1870, Bibcode:2014ApJ...787L...9V, doi:10.1088/2041-8205/787/1/L9, S2CID 118451863


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