WASP-42

WASP-42
Observation data; Epoch J2000 Equinox J2000
Constellation	Centaurus
Right ascension	12h 51m 55.5581s
Declination	−42° 04′ 25.096″
Apparent magnitude (V)	12.6
Characteristics
Evolutionary stage	main-sequence star
Spectral type	K1V
Astrometry
Radial velocity (Rv)	−4.22±0.41 km/s
Proper motion (μ)	RA: −49.875 mas/yr ; Dec.: 4.963 mas/yr
Parallax (π)	5.6209±0.0153 mas
Distance	580 ± 2 ly ; (177.9 ± 0.5 pc)
Details
Mass	0.881+0.086; −0.081 M☉
Radius	0.850±0.035 R☉
Luminosity	0.48 L☉
Surface gravity (log g)	4.52 cgs
Temperature	5,259 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
	TOI-769, TIC 248075138, WASP-42, 2MASS J12515557-4204249
Database references
SIMBAD	data
Exoplanet Archive	data

WASP-42 is a K-type main-sequence star about 580 light-years away in the constellation Centaurus. Its surface temperature is 5315±79 K.^[7] 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.^[3]

Multiplicity surveys did not detect any stellar companions to WASP-42 in 2017.^[8]

Planetary system

In 2012, one planet, named WASP-42b, was discovered^[9] on a tight, mildly eccentric orbit.^[4] The planetary equilibrium temperature is 1,021±19 K.^[3]

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 $M$ _J	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 $R$ _J

References

^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
^ ^a ^b ^c ^d ^e 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.
^ ^a ^b ^c ^d 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, Bibcode:2016MNRAS.457.4205S, doi:10.1093/mnras/stw279, S2CID 44864064
^ ^a ^b ^c ^d ^e ^f ^g ^h 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
^ ^a ^b ^c De Laverny, Patrick; Ligi, Roxanne; Crida, Aurélien; Recio-Blanco, Alejandra; Palicio, Pedro A. (2025). "The Gaia spectroscopic catalogue of exoplanets and host stars". Astronomy & Astrophysics. 699: A100. arXiv:2505.22205. Bibcode:2025A&A...699A.100D. doi:10.1051/0004-6361/202554739.
^ "WASP-42". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-22.
^ Southworth, John; et al. (2016). "High-precision photometry by telescope defocussing – VIII. WASP-22, WASP-41, WASP-42 and WASP-55". Monthly Notices of the Royal Astronomical Society. 457 (4): 4205–4217. arXiv:1512.05549. Bibcode:2016MNRAS.457.4205S. doi:10.1093/mnras/stw279.
^ 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
^ 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

This main-sequence-star-related article is a stub. You can help Wikipedia by expanding it.

This extrasolar-planet-related article is a stub. You can help Wikipedia by expanding it.

[Roman1987-1] Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.

[DR3-2] 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.

[Southworth2015-3] 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, Bibcode:2016MNRAS.457.4205S, doi:10.1093/mnras/stw279, S2CID 44864064

[Bonomo2017-4] ^ ^a ^b ^c ^d ^e ^f ^g ^h 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

[dl2025-5] De Laverny, Patrick; Ligi, Roxanne; Crida, Aurélien; Recio-Blanco, Alejandra; Palicio, Pedro A. (2025). "The Gaia spectroscopic catalogue of exoplanets and host stars". Astronomy & Astrophysics. 699: A100. arXiv:2505.22205. Bibcode:2025A&A...699A.100D. doi:10.1051/0004-6361/202554739.

[SIMBAD-6] "WASP-42". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-22.

[southworth2016-7] Southworth, John; et al. (2016). "High-precision photometry by telescope defocussing – VIII. WASP-22, WASP-41, WASP-42 and WASP-55". Monthly Notices of the Royal Astronomical Society. 457 (4): 4205–4217. arXiv:1512.05549. Bibcode:2016MNRAS.457.4205S. doi:10.1093/mnras/stw279.

[evans2018-8] 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

[Lendl2012-9] 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

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

Observation data Epoch J2000 Equinox J2000
Constellation	Centaurus^[1]
Right ascension	12^h 51^m 55.5581^s^[2]
Declination	−42° 04′ 25.096″^[2]
Apparent magnitude (V)	12.6^[3]
Characteristics
Evolutionary stage	main-sequence star
Spectral type	K1V^[3]
Astrometry

Radial velocity (R_v)	−4.22±0.41^[2] km/s
Proper motion (μ)	RA: −49.875 mas/yr^[2] Dec.: 4.963 mas/yr^[2]
Parallax (π)	5.6209±0.0153 mas^[2]
Distance	580 ± 2 ly (177.9 ± 0.5 pc)

Details

Mass	0.881^+0.086 _−0.081^[4] `M`_☉
Radius	0.850±0.035^[4] `R`_☉
Luminosity	0.48^[5] `L`_☉
Surface gravity (log g)	4.52^[5] cgs
Temperature	5,259^[5] K
Metallicity [Fe/H]	0.05±0.13^[4] dex
Rotational velocity (v sin i)	2.70±0.40^[4] km/s
Age	11.3^+1.5 _−4.8^[4] Gyr

Other designations
TOI-769, TIC 248075138, WASP-42, 2MASS J12515557-4204249^[6]
Database references
SIMBAD	data
Exoplanet Archive	data

WASP-42

WASP-42

WASP-42

Add your contribution

Hub overview

Root Wikipedia Article

WASP-42

Planetary system

References