WASP-42

WASP-42

Observation data Epoch J2000      Equinox J2000
Constellation	Centaurus
Right ascension	12^h 51^m 55.5580^s[1]
Declination	−42° 04′ 25.095″[1]
Apparent magnitude (V)	12.6[2]
Characteristics
Evolutionary stage	main-sequence star
Spectral type	K1V[2]
Astrometry
Radial velocity (Rv)	41.25[3] km/s
Proper motion (μ)	RA: −49.875[3] mas/yr Dec.: 4.963[3] mas/yr
Parallax (π)	5.6209 ± 0.0153 mas[3]
Distance	580 ± 2 ly (177.9 ± 0.5 pc)
Details[4]
Mass	0.881^+0.086 −0.081 M☉
Radius	0.850±0.035 R☉
Surface gravity (log g)	4.50±0.18[5] cgs
Temperature	5315±79[2] K
Metallicity [Fe/H]	0.05±0.13 dex
Rotational velocity (v sin i)	2.70±0.40 km/s
Age	11.3^+1.5 −4.8 Gyr
Other designations
2MASS J12515557-4204249[1]
Database references
SIMBAD	data

WASP-42 is a K-type main-sequence star. Its surface temperature is 5315±79 K.[6] WASP-42 is similar to the Sun in concentration of heavy elements, with metallicity ([Fe/H]) of 0.05±0.13, and is much older than the Sun at 11.3+1.5
−4.8 billion years.[4] The star does exhibit starspot activity as is typical for its spectral class.[2]

Multiplicity surveys did not detect any stellar companions to WASP-42 in 2017.[7]

Planetary system

In 2012, one planet, named WASP-42b, was discovered[8] on a tight, mildly eccentric orbit.[4] The planetary equilibrium temperature is 1021±19 K.[2]

The WASP-42 planetary system[4]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.501±0.034 MJ	0.0548^+0.0017 −0.0018	4.9816872±0.0000073	0.062^+0.013 −0.011	88.30^+0.26 −0.23°	1.063±0.051 RJ

References

1. "WASP-42". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-22.
2. Southworth, John; Tregloan-Reed, J.; Andersen, M. I.; Calchi Novati, S.; Ciceri, S.; Colque, J. P.; D'Ago, G.; Dominik, M.; Evans, D.; Gu, S. -H.; Herrera-Cruces, A.; Hinse, T. C.; Jorgensen, U. G.; Juncher, D.; Kuffmeier, M.; Mancini, L.; Peixinho, N.; Popovas, A.; Rabus, M.; Skottfelt, J.; Tronsgaard, R.; Unda-Sanzana, E.; Wang, X. -B.; Wertz, O.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; Bramich, D. M.; Burgdorf, M.; et al. (2015), High-precision photometry by telescope defocussing. III. WASP-22, WASP-41, WASP-42 and WASP-55, arXiv:1512.05549, doi:10.1093/mnras/stw279, S2CID 44864064
3. 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. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
4. Bonomo, A. S.; Desidera, S.; Benatti, S.; Borsa, F.; Crespi, S.; Damasso, M.; Lanza, A. F.; Sozzetti, A.; Lodato, G.; Marzari, F.; Boccato, C.; Claudi, R. U.; Cosentino, R.; Covino, E.; Gratton, R.; Maggio, A.; Micela, G.; Molinari, E.; Pagano, I.; Piotto, G.; Poretti, E.; Smareglia, R.; Affer, L.; Biazzo, K.; Bignamini, A.; Esposito, M.; Giacobbe, P.; Hébrard, G.; Malavolta, L.; et al. (2017), "The GAPS Programme with HARPS-N@TNG XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets", Astronomy & Astrophysics, A107: 602, arXiv:1704.00373, Bibcode:2017A&A...602A.107B, doi:10.1051/0004-6361/201629882, S2CID 118923163
5. Mortier, A.; Santos, N. C.; Sousa, S. G.; Fernandes, J. M.; Adibekyan, V. Zh.; Delgado Mena, E.; Montalto, M.; Israelian, G. (2013), "New and updated stellar parameters for 90 transit hosts The effect of the surface gravity", Astronomy and Astrophysics, 558: A106, arXiv:1309.1998, Bibcode:2013A&A...558A.106M, doi:10.1051/0004-6361/201322240, S2CID 118750676
6. Southworth, J. (2016). "4. Physical Properties". High-precision photometry by telescope defocussing (PDF). Vol. VIII. WASP-22, WASP-41, WASP-41 and WASP-55. p. 4210. doi:10.1093/mnras/stw279. Retrieved 25 October 2023.
7. Evans, D. F.; Southworth, J.; Smalley, B.; Jørgensen, U. G.; Dominik, M.; Andersen, M. I.; Bozza, V.; Bramich, D. M.; Burgdorf, M. J.; Ciceri, S.; d'Ago, G.; Figuera Jaimes, R.; Gu, S.-H.; Hinse, T. C.; Henning, Th.; Hundertmark, M.; Kains, N.; Kerins, E.; Korhonen, H.; Kokotanekova, R.; Kuffmeier, M.; Longa-Peña, P.; Mancini, L.; MacKenzie, J.; Popovas, A.; Rabus, M.; Rahvar, S.; Sajadian, S.; Snodgrass, C.; et al. (2018), "High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP). II. Lucky Imaging results from 2015 and 2016", Astronomy & Astrophysics, 610: A20, arXiv:1709.07476, Bibcode:2018A&A...610A..20E, doi:10.1051/0004-6361/201731855, S2CID 53400492
8. Lendl, M.; Anderson, D. R.; Collier-Cameron, A.; Doyle, A. P.; Gillon, M.; Hellier, C.; Jehin, E.; Lister, T. A.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Smalley, B.; Ségransan, D.; Smith, A. M. S.; Triaud, A. H. M. J.; Udry, S.; West, R. G.; Wheatley, P. J. (2012), "WASP-42 b and WASP-49 b: two new transiting sub-Jupiters", Astronomy & Astrophysics, 544: A72, arXiv:1205.2757, Bibcode:2012A&A...544A..72L, doi:10.1051/0004-6361/201219585, S2CID 54186638