Draft:TOI-421
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lepus |
| Right ascension | 05h 27m 24.8259s[1] |
| Declination | −14° 16′ 37.046″[1] |
| Apparent magnitude (V) | 9.93[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G9V[3] |
| Astrometry | |
| Radial velocity (Rv) | 79.41±0.16[1] km/s |
| Proper motion (μ) | RA: −35.743±0.011 mas/yr[1] Dec.: 50.387±0.011 mas/yr[1] |
| Parallax (π) | 13.3337 ± 0.0117 mas[1] |
| Distance | 244.6 ± 0.2 ly (75.00 ± 0.07 pc) |
| Details[4] | |
| Mass | 0.833+0.048 −0.054 M☉ |
| Radius | 0.866±0.006 R☉ |
| Surface gravity (log g) | 4.48±0.03 cgs |
| Temperature | 5291±64 K |
| Metallicity [Fe/H] | −0.044±0.04 dex |
| Rotation | 39.6±1.6 d |
| Rotational velocity (v sin i) | 1.8±1.0[3] km/s |
| Age | 10.9+2.9 −5.2 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
TOI-421 (also known as BD−14 1137)[5] is a G-type main-sequence star hosting a planetary system located in the constellation Lepus.
The star forms a visual binary system with a nearby red dwarf star 29.4″ away, corresponding to actual separation of approximately 2200 AU.[3]
Stellar characteristics
[edit]Planetary system
[edit]A discovery of two planets transiting the star was announced in 2020, based on TESS observations between 15 November 2018 and 7 January 2019, and confirmed with ground-based observations. The TESS light curve features two series of transit signals identified with the two planets; a deeper one every ~16.1 days and a shallower one every ~5.2 days.[3] The orbital parameters were refined in a 2024 study that included additional transit observations by TESS and CHEOPS as well as radial velocity measurements.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 6.7±0.6 M🜨 | 0.0554±0.0010 | 5.197576±0.000005 | 0.13±0.05 | 85.68+0.36 −0.46° |
2.64±0.08 R🜨 |
| c | 14.1±1.4 M🜨 | 0.1170±0.0018 | 16.067541±0.000004 | 0.19±0.04 | 88.353+0.078 −0.084° |
5.09±0.07 R🜨 |
The planet b is a hot mini-Neptune while the planet c is a hot Neptune with a low calculated density of 0.685+0.080
−0.072 g⋅cm−3, belonging to the super-puff class.[3]
Both planets were found to be well-suited for atmospheric characterization.[3]
(Davenport 2025)[6]
References
[edit]- ^ 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.
- ^ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27 – L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
- ^ a b c d e f g Carleo, Ilaria; et al. (2020). "The Multiplanet System TOI-421: A Warm Neptune and a Super Puffy Mini-Neptune Transiting a G9 V Star in a Visual Binary". The Astronomical Journal. 160 (3): 114. doi:10.3847/1538-3881/aba124.
- ^ a b c Krenn, A. F.; et al. (2024). "Characterisation of the TOI-421 planetary system using CHEOPS, TESS, and archival radial velocity data". Astronomy & Astrophysics. 686: A301. arXiv:2404.11074. Bibcode:2024A&A...686A.301K. doi:10.1051/0004-6361/202348584.
- ^ "BD-14 1137". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2025-01-09.
- ^ Davenport, Brian; Kempton, Eliza M. -R.; Nixon, Matthew C.; Ih, Jegug; Deming, Drake; Fu, Guangwei; May, E. M.; Bean, Jacob L.; Gao, Peter; Rogers, Leslie; Malik, Matej (2025). "TOI-421 b: A Hot Sub-Neptune with a Haze-Free, Low Mean Molecular Weight Atmosphere". The Astrophysical Journal Letters. arXiv:2501.01498.
