 Size comparison between Sun and WASP-21 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pegasus[1] |
| Right ascension | 23h 09m 58.25s[2] |
| Declination | +18° 23′ 45.9″[2] |
| Apparent magnitude (V) | 11.58±0.08[3] |
| Characteristics | |
| Evolutionary stage | subgiant[2][4] |
| Spectral type | G3V[5] |
| Astrometry | |
| Radial velocity (Rv) | −89.21±0.46[2] km/s |
| Proper motion (μ) | RA: +17.567(21) mas/yr[2] Dec.: +18.639(18) mas/yr[2] |
| Parallax (π) | 3.9089±0.0197 mas[2] |
| Distance | 834 ± 4 ly (256 ± 1 pc) |
| Absolute magnitude (MV) | 4.97[3] |
| Details | |
| Mass | 0.89±0.071[6] M☉ |
| Radius | 1.136±0.049[6] R☉ |
| Luminosity | 1.4[7] L☉ |
| Surface gravity (log g) | 4.277±0.025[6] cgs |
| Temperature | 5,800±100[3] K |
| Metallicity | −0.4±0.1[3] |
| Metallicity [Fe/H] | −0.46±0.11[3] dex |
| Rotational velocity (v sin i) | 1.5±0.6[3] km/s |
| Age | 12±5[3] Gyr |
| Other designations | |
| Tangra, TOI-5963, TIC 436478932, WASP-21, GSC 01715-00679, 2MASS J23095825+1823459[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
WASP-21, also named Tangra, is a G-type star (spectral type G3V) that has reached the end of its main sequence lifetime.[4][9] It lies approximately 834 light-years away, in the constellation of Pegasus. The star is relatively metal-poor, having 40% of heavy elements compared to the Sun.[9] Kinematically, WASP-21 belongs to the thick disk of the Milky Way.[3] It has an exoplanet named WASP-21b.[10]
A survey in 2012 failed to find any stellar companions to WASP-21.[11]
Naming
In 2019 the WASP-21 system was chosen as part of the NameExoWorlds campaign organised by the International Astronomical Union, which assigned each country a star and planet to be named. WASP-21 was assigned to Bulgaria. The winning proposal named the star Tangra after a deity worshipped by the early Bulgars, and the planet Bendida after a deity worshipped by the Thracians.[12]
Planetary system
In 2010 WASP-21 was discovered to host a hot Jupiter type planet by the Wide Angle Search for Planets (WASP),[3] confirmed by radial velocity by the WASP team in 2010.
Transit-timing variation analysis in 2015 did not find any additional planets in the system.[9]
In 2020, spectroscopic analysis found that the WASP-21b atmosphere is mostly cloudless and contains sodium.[13]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Bendida | 0.276 ± 0.018 MJ | 0.0499 ± 0.0013 | 4.322482 | <0.048[14] | 86.97 ± 0.33° | 1.162 RJ |
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 f 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 e f g h i Bouchy, F.; Hebb, L.; Skillen, I.; Collier Cameron, A.; Smalley, B.; Udry, S.; Anderson, D. R.; Boisse, I.; Enoch, B.; Haswell, C. A.; Hébrard, G.; Hellier, C.; Joshi, Y.; Kane, S. R.; Maxted, P. F. L.; Mayor, M.; Moutou, C.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Simpson, E. K.; Smith, A. M. S.; Stempels, H. C.; Street, R.; Triaud, A. H. M. J.; West, R. G.; Wheatley, P. J. (2010). "WASP-21b: A hot-Saturn exoplanet transiting a thick disc star". Astronomy and Astrophysics. 519: A98. arXiv:1006.2605. Bibcode:2010A&A...519A..98B. doi:10.1051/0004-6361/201014817. S2CID 119182669.
- ^ a b Barros, S. C. C.; Pollacco, D. L.; Gibson, N. P.; Howarth, I. D.; Keenan, F. P.; Simpson, E. K.; Skillen, I.; Steele, I. A. (2011). "A lower mass for the exoplanet WASP-21b". Monthly Notices of the Royal Astronomical Society. 416 (4): 2593–2599. arXiv:1106.2118. Bibcode:2011MNRAS.416.2593B. doi:10.1111/j.1365-2966.2011.19210.x. S2CID 56165266.
- ^ Ehrenreich, D.; Désert, J. -M. (2011). "Mass-loss rates for transiting exoplanets". Astronomy and Astrophysics. 529: A136. arXiv:1103.0011. Bibcode:2011A&A...529A.136E. doi:10.1051/0004-6361/201016356.
- ^ a b c d Ciceri, S.; Mancini, L.; Southworth, J.; Nikolov, N.; Bozza, V.; Bruni, I.; Calchi Novati, S.; d'Ago, G.; Henning, Th. (2013). "Simultaneous follow-up of planetary transits: Revised physical properties for the planetary systems HAT-P-16 and WASP-21". Astronomy & Astrophysics. 557: A30. arXiv:1307.5874. Bibcode:2013A&A...557A..30C. doi:10.1051/0004-6361/201321669. S2CID 55192357.
- ^ Loyd, R. O. Parke; Shkolnik, Evgenya L.; Schneider, Adam C.; Richey-Yowell, Tyler; Barman, Travis S.; Peacock, Sarah; Pagano, Isabella (2020). "Current Population Statistics do Not Favor Photoevaporation over Core-powered Mass Loss as the Dominant Cause of the Exoplanet Radius Gap". The Astrophysical Journal. 890 (1): 23. arXiv:1912.12305. Bibcode:2020ApJ...890...23L. doi:10.3847/1538-4357/ab6605.
- ^ "WASP-21". SIMBAD. Centre de données astronomiques de Strasbourg.
- ^ a b c d Seeliger, M.; Kitze, M.; Errmann, R.; Richter, S.; Ohlert, J. M.; Chen, W. P.; Guo, J. K.; Göğüş, E.; Güver, T.; Aydın, B.; Mottola, S.; Hellmich, S.; Fernandez, M.; Aceituno, F. J.; Dimitrov, D.; Kjurkchieva, D.; Jensen, E.; Cohen, D.; Kundra, E.; Pribulla, T.; Vaňko, M.; Budaj, J.; Mallonn, M.; Wu, Z.-Y.; Zhou, X.; Raetz, St.; Adam, C.; Schmidt, T. O. B.; Ide, A.; et al. (2015), "Ground-based transit observations of the HAT-P-18, HAT-P-19, HAT-P-27/WASP40 and WASP-21 systems", Monthly Notices of the Royal Astronomical Society, 451 (4): 4060–4072, arXiv:1508.06215, Bibcode:2015MNRAS.451.4060S, doi:10.1093/mnras/stv1187, S2CID 56034663
- ^ "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. 2 October 2017. Retrieved 2022-12-10.
- ^ Ginski, C.; Mugrauer, M.; Seeliger, M.; Eisenbeiss, T. (2012), "A lucky imaging multiplicity study of exoplanet host stars", Monthly Notices of the Royal Astronomical Society, 421 (3): 2498–2509, arXiv:1202.4586, Bibcode:2012MNRAS.421.2498G, doi:10.1111/j.1365-2966.2012.20485.x, S2CID 118573795
- ^ "Bulgaria | NameExoworlds". Name Exoworlds. 2019-12-17. Retrieved 2019-12-30.
- ^ Chen, G.; Casasayas-Barris, N.; Pallé, E.; Welbanks, L.; Madhusudhan, N.; Luque, R.; Murgas, F. (2020), "Detection of Na in WASP-21b's lower and upper atmosphere", Astronomy & Astrophysics, 642: A54, arXiv:2007.13429, Bibcode:2020A&A...642A..54C, doi:10.1051/0004-6361/202038661, S2CID 220793336
- ^ 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.
