Astronomy:V1298 Tauri

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Short description: Star in the constellation Taurus
V1298 Tauri
YGLQobc(1).png
The planetary system V1298 Tauri
Credit: Exoplanet Exploration Program and the Jet Propulsion Laboratory for NASA’s Astrophysics Division
Observation data
Equinox J2000.0]] (ICRS)
Constellation Taurus
Right ascension  04h 05m 19.59121s[1]
Declination +20° 09′ 25.5635″[1]
Apparent magnitude (V) 10.31 - 10.43[2]
Characteristics
Spectral type K0-K1.5[3]
Variable type Irregular[2]
Astrometry
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)
Details
Mass1.095+0.049
−0.047
[4] M
Radius1.33+0.04
−0.03
[4] R
Luminosity0.934 ± 0.044[3] L
Temperature4970 ± 120[3] K
Rotation2.97+0.03
−0.04
 d
[4]
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
SIMBADdata

V1298 Tauri is a young (23±4 Myr) weakly-lined T Tauri star[5] 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.[6][7][3] The system has four transiting exoplanets, discovered with the Kepler space telescope in the K2 mission.[5] One of the planets was discovered in August 2019[3] and the other three were discovered in November 2019 by the same team.[5]

Stellar characteristics

A light curve for V1298 Tauri, adapted from David et al. (2019)[3]

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.[6]

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.[5]

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.[5] In a follow-up paper the mass of V1298 Tauri b was constrained to <2.2 ||J}}}}}}.[8] 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.[9]

Orbits of the planets b and c are nearly coplanar and planet c is not inclined to the equatorial plane of the star, misalignment equals to 2+12−4 degrees.[10]

The V 1298 Tauri planetary system[5][8]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
c 0.0825 ± 0.0013 8.24958 ± 0.00072 <0.43 88.49+0.92
−0.72
°
0.499+0.032
−0.029
 RJ
d 0.1083 ± 0.0017 12.4032 ± 0.0015 <0.21 89.04+0.65
−0.73
°
0.572+0.040
−0.035
 RJ
b <2.2 MJ 0.1688 ± 0.0026 24.1396 ± 0.0018 <0.29 89.00+0.46
−0.24
°
0.916+0.052
−0.047
 RJ
e 0.308+0.182
−0.066
50.29±6.62[11] <0.57 89.40+0.26
−0.18
°
0.89±0.04[11] RJ

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 Gaia Collaboration (2018-08-01). "Gaia Data Release 2 - Summary of the contents and survey properties" (in en). Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. ISSN 0004-6361. Bibcode2018A&A...616A...1G. 
  2. 2.0 2.1 2.2 Samus, N. N. 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. Bibcode2009yCat....102025S. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 David, Trevor J.; Cody, Ann Marie; Hedges, Christina L.; Mamajek, Eric E.; Hillenbrand, Lynne A.; Ciardi, David R.; Beichman, Charles A.; Petigura, Erik A. et al. (August 2019). "A Warm Jupiter-sized Planet Transiting the Pre-main-sequence Star V1298 Tau" (in en). The Astronomical Journal 158 (2): 79. doi:10.3847/1538-3881/ab290f. ISSN 0004-6256. Bibcode2019AJ....158...79D. 
  4. 4.0 4.1 4.2 Feinstein, Adina D.; David, Trevor J.; Montet, Benjamin T.; Foreman-Mackey, Daniel; Livingston, John H.; Mann, Andrew W. (2022). "V1298 Tau with TESS: Updated Ephemerides, Radii, and Period Constraints from a Second Transit of V1298 Tau E". The Astrophysical Journal Letters 925 (1): L2. doi:10.3847/2041-8213/ac4745. Bibcode2022ApJ...925L...2F. 
  5. 5.0 5.1 5.2 5.3 5.4 5.5 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. doi:10.3847/2041-8213/ab4c99. ISSN 2041-8213. Bibcode2019ApJ...885L..12D. 
  6. 6.0 6.1 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" (in en). The Astronomical Journal 153 (6): 257. doi:10.3847/1538-3881/aa6ffd. ISSN 0004-6256. Bibcode2017AJ....153..257O. 
  7. Luhman, K. L. (December 2018). "The Stellar Membership of the Taurus Star-forming Region" (in en). The Astronomical Journal 156 (6): 271. doi:10.3847/1538-3881/aae831. ISSN 0004-6256. Bibcode2018AJ....156..271L. 
  8. 8.0 8.1 Beichman, Charles; Hirano, Teruyuki; David, Trevor J.; Kotani, Takayuki; Hillenbrand, Lynne A.; Vasisht, Gautam; Ciardi, David R.; Harakawa, Hiroki et al. (June 2019). "A Mass Limit for the Young Transiting Planet V1298 Tau b" (in en). Research Notes of the AAS 3 (6): 89. doi:10.3847/2515-5172/ab2c9d. ISSN 2515-5172. Bibcode2019RNAAS...3...89B. 
  9. Schlawin, Everett; Ilyin, Ilya; Feinstein, Adina D.; Bean, Jacob; Huang, Chenliang; Gao, Peter; Strassmeier, Klaus; Poppenhaeger, Katja (2021), "H-Alpha Variability of V1298 Tau c", Research Notes of the American Astronomical Society 5 (8): 195, doi:10.3847/2515-5172/ac1f2f, Bibcode2021RNAAS...5..195S 
  10. Gaidos, E.; Hirano, T.; Beichman, C.; Livingston, J.; Harakawa, H.; Hodapp, K. W.; Ishizuka, M.; Jacobson, S. et al. (2022), "Zodiacal exoplanets in time – XIII. Planet orbits and atmospheres in the V1298 Tau system, a keystone in studies of early planetary evolution", Monthly Notices of the Royal Astronomical Society 509 (2): 2969–2978, doi:10.1093/mnras/stab3107 
  11. 11.0 11.1 Feinstein, Adina D.; David, Trevor J.; Montet, Benjamin T.; Foreman-Mackey, Daniel; Livingston, John H.; Mann, Andrew W. (2022), "V1298 Tau with TESS: Updated Ephemerides, Radii, and Period Constraints from a Second Transit of V1298 Tau E", The Astrophysical Journal Letters 925 (1): L2, doi:10.3847/2041-8213/ac4745, Bibcode2022ApJ...925L...2F