2MASS J0558 (also known as 2MASS J05581644–4501559) is a young red dwarf. It has one planetary-mass object orbiting it at a separation of 1043 astronomical units.[2]
 2MASS J0558 and its companion (white cross-hair at the bottom) Credit: Legacy Surveys / D.Lang (Perimeter Institute) & Meli thev | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pictor |
| Right ascension | 05h 58m 16.44s |
| Declination | −45° 01′ 55.98″ |
| Apparent magnitude (V) | 14.928 ±0.01[1] |
| Characteristics | |
| Evolutionary stage | red dwarf |
| Spectral type | M4V[2] |
| Variable type | flare star[2] |
| Astrometry | |
| Radial velocity (Rv) | 11.04 ±3.62[3] km/s |
| Proper motion (μ) | RA: -66.975 ±0.014 mas/yr[3] Dec.: 61.824 ±0.016 mas/yr[3] |
| Parallax (π) | 37.0938 ± 0.0119 mas[3] |
| Distance | 87.93 ± 0.03 ly (26.959 ± 0.009 pc) |
| Details[1][2] | |
| Mass | 0.230 ±0.007 M☉ |
| Radius | 0.260 ±0.008 R☉ |
| Luminosity | 5.95e-03 ±1.74e-04 L☉ |
| Temperature | 3232 ±107 K |
| Age | 120-650 Myr |
| Other designations | |
| Database references | |
| 0558A | |
| SIMBAD | data |
| 0558B | |
| SIMBAD | data |
The host star
editThe primary was observed at the Southern African Large Telescope (SALT) and the spectrum agrees with an M4V spectral type. The star shows several features of youth, such as H-alpha emission and likely shallower absorption due to TiO, CaH and FeH. TESS shows a variability with a period of 1.56 days and several flares. A short rotation period and the frequency of flares also agree with a young age. The researchers use the rotation period to determine an age limit of 120-650 Million years (Myr). The higher brightness in ultraviolet and maybe x-ray from GALEX and ROSAT are also in agreement with this age. The researchers find that the star could be a member of the 30-100 Myr old Octans-Near moving group, but the nature of this moving group is disputed.[2]
Planetary system
editCWISEP J055816.68-450233.6 was first identified as a possible proper motion object by the CatWISE team in 2020 in WISE data and with Spitzer follow-up. But this team was not able to confirm the motion of this object.[4] Follow-up observations with Magellan/FIRE showed a near-infrared spectral type of T8.5 and it was mentioned for the first time that it could be a companion to 2MASS J0558 (see table 2).[5] In 2024 it was discovered that this T-dwarf co-moves with 2MASS J0558 from WISE/NEOWISE data and it was given the name 0558B. The pair is separated by 38.67 arcseconds. The paper also mentions which citizen scientist from the backyard worlds project discovered this object. The discoverers are the CatWISE team, Arttu Sainio, Dan Caselden and Jim Walla. The spectrum does not show strong peculiarities and the companion was classified as a T8. It does show enhanced K-band spectrum, but it is not clear if this is a sign of youth. From the age of the primary, the secondary has a mass of 6-12 MJ, meaning it is below the deuterium-burning limit. This makes this object a planetary-mass companion.[2]
See also
editReferences
edit- ^ a b Hardegree-Ullman, Kevin K.; Apai, Dániel; Bergsten, Galen J.; Pascucci, Ilaria; López-Morales, Mercedes (2023-06-01). "Bioverse: A Comprehensive Assessment of the Capabilities of Extremely Large Telescopes to Probe Earth-like O2 Levels in Nearby Transiting Habitable-zone Exoplanets". The Astronomical Journal. 165 (6): 267. arXiv:2304.12490. Bibcode:2023AJ....165..267H. doi:10.3847/1538-3881/acd1ec. ISSN 0004-6256.
- ^ a b c d e f Marocco, Federico; Kirkpatrick, J. Davy; Schneider, Adam C.; Meisner, Aaron M.; Popinchalk, Mark; Gelino, Christopher R.; Faherty, Jacqueline K.; Burgasser, Adam J.; Caselden, Dan; Gagné, Jonathan; Aganze, Christian; Bardalez-Gagliuffi, Daniella C.; Casewell, Sarah L.; Hsu, Chih-Chun; Kiman, Rocio; Eisenhardt, Peter R. M.; Kuchner, Marc J.; Stern, Daniel; Gramaize, Léopold; Sainio, Arttu; Bickle, Thomas P.; Rothermich, Austin; Pendrill, William; Thévenot, Melina; Kabatnik, Martin; Colombo, Giovanni; Higashimura, Hiro; Kiwy, Frank; Marchese, Elijah J.; Andersen, Nikolaj Stevnbak; Tanner, Christopher; Walla, Jim; Wedracki, Zbigniew; The Backyard Worlds Collaboration (2024-04-22). "Thirteen New M Dwarf + T Dwarf Pairs Identified with WISE/NEOWISE". The Astrophysical Journal. 967 (2): 147. arXiv:2404.14324. Bibcode:2024ApJ...967..147M. doi:10.3847/1538-4357/ad3f1d.
- ^ a b c 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.
- ^ Meisner, Aaron M.; Caselden, Dan; Kirkpatrick, J. Davy; Marocco, Federico; Gelino, Christopher R.; Cushing, Michael C.; Eisenhardt, Peter R. M.; Wright, Edward L.; Faherty, Jacqueline K.; Koontz, Renata; Marchese, Elijah J.; Khalil, Mohammed; Fowler, John W.; Schlafly, Edward F. (2020-02-01). "Expanding the Y Dwarf Census with Spitzer Follow-up of the Coldest CatWISE Solar Neighborhood Discoveries". The Astrophysical Journal. 889 (2): 74. arXiv:1911.12372. Bibcode:2020ApJ...889...74M. doi:10.3847/1538-4357/ab6215. ISSN 0004-637X.
- ^ Kirkpatrick, J. Davy; Marocco, Federico; Gelino, Christopher R.; Raghu, Yadukrishna; Faherty, Jacqueline K.; Bardalez Gagliuffi, Daniella C.; Schurr, Steven D.; Apps, Kevin; Schneider, Adam C.; Meisner, Aaron M.; Kuchner, Marc J.; Caselden, Dan; Smart, R. L.; Casewell, S. L.; Raddi, Roberto (2024-04-01). "The Initial Mass Function Based on the Full-sky 20 pc Census of ∼3600 Stars and Brown Dwarfs". The Astrophysical Journal Supplement Series. 271 (2): 55. arXiv:2312.03639. Bibcode:2024ApJS..271...55K. doi:10.3847/1538-4365/ad24e2. ISSN 0067-0049.