WASP-84, also known as BD+02 2056, is a G-type main-sequence star 327 light-years (100 parsecs) away in the constellation Hydra. Its surface temperature is 5350±31 K and is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.05±0.02. It is rich in carbon and depleted of oxygen.[5] WASP-84's age is probably older than the Sun at 8.5+4.1
−5.5 billion years.[4] The star appears to have an anomalously small radius, which can be explained by the unusually high helium fraction or by it being very young.[7]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra[1] |
| Right ascension | 08h 44m 25.70315s[2] |
| Declination | +01° 51′ 36.1055″[2] |
| Apparent magnitude (V) | 10.83 |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | G9V[3] |
| Astrometry | |
| Radial velocity (Rv) | −11.63±0.21[2] km/s |
| Proper motion (μ) | RA: −23.344 mas/yr[2] Dec.: −31.570 mas/yr[2] |
| Parallax (π) | 9.9636±0.0149 mas[2] |
| Distance | 327.3 ± 0.5 ly (100.4 ± 0.2 pc) |
| Details | |
| Mass | 0.842+0.037 −0.036[4] M☉ |
| Radius | 0.748±0.015[4] R☉ |
| Luminosity | 0.48[2] L☉ |
| Surface gravity (log g) | 4.63±0.06[5] cgs |
| Temperature | 5350±31[5] K |
| Metallicity [Fe/H] | 0.05±0.02[5] dex |
| Rotation | 14.36±0.35 d[4] |
| Rotational velocity (v sin i) | 4.10±0.30[4] km/s |
| Age | 8.5+4.1 −5.5[4] Gyr |
| Other designations | |
| BD+02 2056, Gaia DR2 3078836109158636928, WASP-84, TYC 211-706-1, GSC 00211-00706, 2MASS J08442570+0151361[6] | |
| Database references | |
| SIMBAD | data |
A multiplicity survey did not detect any stellar companions to WASP-84 as of 2015.[8]
Planetary system
editIn 2013, one exoplanet, named WASP-84b, was discovered on a tight, circular orbit.[9] The planet is a hot Jupiter that cannot have formed in its current ___location and likely migrated from elsewhere. The planetary orbit is well aligned with the equatorial plane of the star, misalignment being equal to 0.3±1.7°. Planetary equilibrium temperature is 832±13 K.[3]
In 2023, a second planet was discovered around WASP-84. This appears to be a dense rocky planet despite its high mass, comparable to Uranus.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| c | 15.2+4.5 −4.2 M🜨 |
0.02359±0.00100 | 1.4468849+0.0000022 −0.0000016 |
— | 83.20+0.51 −0.49° |
1.95±0.12 R🜨 |
| b | 0.692±0.058 MJ | 0.0778±0.0021 | 8.52349648(60) | <0.077[4] | 88.292+0.045 −0.042° |
0.956±0.024 RJ |
References
edit- ^ 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 g 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 Anderson, D. R.; Triaud, A. H. M. J.; Turner, O. D.; Brown, D. J. A.; Clark, B. J. M.; Smalley, B.; Cameron, A. Collier; Doyle, A. P.; Gillon, M.; Hellier, C.; Lovis, C.; Maxted, P. F. L.; Pollacco, D.; Queloz, D.; Smith, A. M. S. (2015), "THE WELL-ALIGNED ORBIT OF WASP-84b: EVIDENCE FOR DISK MIGRATION OF a HOT JUPITER", The Astrophysical Journal, 800 (1): L9, arXiv:1409.6335, Bibcode:2015ApJ...800L...9A, doi:10.1088/2041-8205/800/1/L9, S2CID 13606807
- ^ a b c d e f g 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 d Teske, Johanna K.; Thorngren, Daniel; Fortney, Jonathan J.; Hinkel, Natalie; Brewer, John M. (2019), "Do Metal-rich Stars Make Metal-rich Planets? New Insights on Giant Planet Formation from Host Star Abundances", The Astronomical Journal, 158 (6): 239, arXiv:1912.00255, Bibcode:2019AJ....158..239T, doi:10.3847/1538-3881/ab4f79, S2CID 208527082
- ^ "BD+02 2056". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-25.
- ^ Maxted, P. F. L.; Serenelli, A. M.; Southworth, J. (2015), "Comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars", Astronomy & Astrophysics, 577: A90, arXiv:1503.09111, Bibcode:2015A&A...577A..90M, doi:10.1051/0004-6361/201525774, S2CID 53324330
- ^ Wöllert, Maria; Brandner, Wolfgang (2015), "A Lucky Imaging search for stellar sources near 74 transit hosts", Astronomy & Astrophysics, 579: A129, arXiv:1506.05456, Bibcode:2015A&A...579A.129W, doi:10.1051/0004-6361/201526525, S2CID 118903879
- ^ Anderson, D. R.; Collier Cameron, A.; Delrez, L.; Doyle, A. P.; Faedi, F.; Fumel, A.; Gillon, M.; Gómez Maqueo Chew, Y.; Hellier, C.; Jehin, E.; Lendl, M.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Skillen, I.; Smalley, B.; Smith, A. M. S.; Southworth, J.; Triaud, A. H. M. J.; Turner, O. D.; Udry, S.; West, R. G. (2014), "Three newly discovered sub-Jupiter-mass planets: WASP-69b and WASP-84b transit active K dwarfs and WASP-70Ab transits the evolved primary of a G4+K3 binary", Monthly Notices of the Royal Astronomical Society, 445 (2): 1114–1129, arXiv:1310.5654, Bibcode:2014MNRAS.445.1114A, doi:10.1093/mnras/stu1737, S2CID 54750890
- ^ a b Maciejewski, G.; Golonka, J.; et al. (May 2023). "A hot super-Earth planet in the WASP-84 planetary system". Monthly Notices of the Royal Astronomical Society. 525 (1): L43 – L49. arXiv:2305.09177. Bibcode:2023MNRAS.525L..43M. doi:10.1093/mnrasl/slad078.