V1298 Tauri


V1298 Tauri
The planetary system V1298 Tauri
Credit: Exoplanet Exploration Program and the Jet Propulsion Laboratory for NASA’s Astrophysics Division
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Taurus
Right ascension 04h 05m 19.59121s[1]
Declination +20° 09′ 25.5635″[1]
Apparent magnitude (V) 10.31 - 10.43[2]
Spectral type K0-K1.5[3]
Variable type Irregular[2]
Proper motion (μ) RA: 5.228 ± 0.131[1] mas/yr
Dec.: -16.077 ± 0.048[1] mas/yr
Parallax (π)9.2139 ± 0.0593[1] mas
Distance354 ± 2 ly
(108.5 ± 0.7 pc)
[4] M
[4] R
Luminosity0.934 ± 0.044[3] L
Temperature4970 ± 120[3] K
Age23 ± 4[3] Myr
Other designations
K2-309, 2MASS J04051959+2009256, BD+19 656, EPIC 210818897, RX J0405.3+2009, 1SWASP J040519.59+200925.5
Database references

V1298 Tauri is a young (23±4 Myr) weakly-lined T Tauri star[4] that is part of the Taurus-Auriga association in the Taurus Molecular Cloud. Alternatively it is part of a proposed moving group, called Group 29 that is slightly older.[5][6][3] The system has four transiting exoplanets, discovered with the Kepler space telescope in the K2 mission.[4] One of the planets was discovered in August 2019[3] and the other three were discovered in November 2019 by the same team.[4]

Stellar characteristics

V1298 Tauri has a spectral type of K0 - K1.5 and it has a mass of about 1.1 M. The star appears in x-rays from ROSAT data and it does show strong lithium absorption lines, both signatures of youth and therefore it was a proposed member of Taurus-Auriga. On the other hand it does not show signs of accretion and it lacks infrared excess. Instead it shows H-alpha in absorption.[3]

The brightness of V1298 Tauri varies in an unpredictable way between a maximum visual magnitude of 10.31 and a minimum of 10.54.[2] The light curve of the star shows quasi-periodic variability that was interpreted as stellar rotation and starspots. The light curve also showed several flares.[3]

Based on Gaia DR2 data this star is part of a co-moving pair, together with HD 284154.[5]

Planetary System

V1298 Tauri has four confirmed planets of which planets c, d and b are near a 1:2:3 resonance (with periods of 8.25, 12.40 and 24.14 days). Planet e only shows a single transit in the K2 light curve and has a period larger than 36 days. Planet e might be in a low-order resonance (of 2:3, 3:5, 1:2, or 1:3) with planet b. The system is very young and might be a precursor of a compact multiplanet system. The 2:3 resonance suggests that some close-in planets may either form in resonances or evolve into them on timescales of less than 10 Myr. The planets in the system have a size between Neptune and Saturn. Only planet b has a size similar to Jupiter.[4]

Models predict that the planets have a minimum core mass of 5 M🜨 and are surrounded by a thick envelope that make up 20% of their mass. The total mass of planet c and d was predicted to be 2 - 28 M🜨 and the total mass of planet d and b was predicted to be 9 - 120 M🜨.[4] In a follow-up paper the mass of V1298 Tauri b was constrained to <2.2 MJ.[7] The planet c was suspected to be shedding mass due to intense irradiation by the host star, but hydrogen tail existence was refuted by 2021.[8]

The V 1298 Tauri planetary system[4][7]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
c 0.0825 ± 0.0013 8.24958 ± 0.00072 <0.43 88.49+0.92
d 0.1083 ± 0.0017 12.4032 ± 0.0015 <0.21 89.04+0.65
b <2.2 MJ 0.1688 ± 0.0026 24.1396 ± 0.0018 <0.29 89.00+0.46
e 0.308+0.182
<0.57 89.40+0.26

See also


  1. ^ a b c d e Gaia Collaboration (2018-08-01). "Gaia Data Release 2 - Summary of the contents and survey properties". Astronomy & Astrophysics. 616: A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. ISSN 0004-6361. S2CID 49211658.
  2. ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
  3. ^ a b c d e f g h David, Trevor J.; Cody, Ann Marie; Hedges, Christina L.; Mamajek, Eric E.; Hillenbrand, Lynne A.; Ciardi, David R.; Beichman, Charles A.; Petigura, Erik A.; Fulton, Benjamin J.; Isaacson, Howard T.; Howard, Andrew W. (August 2019). "A Warm Jupiter-sized Planet Transiting the Pre-main-sequence Star V1298 Tau". The Astronomical Journal. 158 (2): 79. arXiv:1902.09670. Bibcode:2019AJ....158...79D. doi:10.3847/1538-3881/ab290f. ISSN 0004-6256. S2CID 119003936.
  4. ^ a b c d e f g h David, Trevor J.; Petigura, Erik A.; Luger, Rodrigo; Foreman-Mackey, Daniel; Livingston, John H.; Mamajek, Eric E.; Hillenbrand, Lynne A. (2019-10-29). "Four Newborn Planets Transiting the Young Solar Analog V1298 Tau". The Astrophysical Journal. 885 (1): L12. arXiv:1910.04563. Bibcode:2019ApJ...885L..12D. doi:10.3847/2041-8213/ab4c99. ISSN 2041-8213. S2CID 204008446.
  5. ^ a b Oh, Semyeong; Price-Whelan, Adrian M.; Hogg, David W.; Morton, Timothy D.; Spergel, David N. (June 2017). "Comoving Stars in Gaia DR1: An Abundance of Very Wide Separation Comoving Pairs". The Astronomical Journal. 153 (6): 257. arXiv:1612.02440. Bibcode:2017AJ....153..257O. doi:10.3847/1538-3881/aa6ffd. ISSN 0004-6256. S2CID 119351439.
  6. ^ Luhman, K. L. (December 2018). "The Stellar Membership of the Taurus Star-forming Region". The Astronomical Journal. 156 (6): 271. arXiv:1811.01359. Bibcode:2018AJ....156..271L. doi:10.3847/1538-3881/aae831. ISSN 0004-6256. S2CID 119471553.
  7. ^ a b Beichman, Charles; Hirano, Teruyuki; David, Trevor J.; Kotani, Takayuki; Hillenbrand, Lynne A.; Vasisht, Gautam; Ciardi, David R.; Harakawa, Hiroki; Kudo, Tomoyuki; Omiya, Masashi; Kuzuhara, Masayuki (June 2019). "A Mass Limit for the Young Transiting Planet V1298 Tau b". Research Notes of the AAS. 3 (6): 89. Bibcode:2019RNAAS...3...89B. doi:10.3847/2515-5172/ab2c9d. ISSN 2515-5172.
  8. ^ H-Alpha Variability of V1298 Tau c, 2021, arXiv:2108.08851