Astronomy:GI Tauri and GK Tauri

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Short description: Binary star system in the constellation of Taurus

Coordinates: Sky map 04h 33m 34.5627s, +24° 21′ 05.8545″

GI Tauri and GK Tauri
GKTauLightCurve.png
A visual band light curve for GK tauri, adapted from Bouvier et al. (1993)[1]
Observation data
{{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| Epoch J2000      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000}}
Constellation Taurus
GK Tauri
Right ascension  04h 33m 34.5627s[2]
Declination +24° 21′ 05.8545″[2]
Apparent magnitude (V) 15.10
GI Tauri
Right ascension  04h 33m 34.0609s[3]
Declination +24° 21′ 17.0674″[3]
Apparent magnitude (V)
Characteristics
GK Tauri
Evolutionary stage pre-main-sequence star
Spectral type K7[4]
Apparent magnitude (G) 11.990[2]
Variable type T Tau
GI Tauri
Apparent magnitude (G) 12.608[3]
Astrometry
GK Tauri
Proper motion (μ) RA: 7.46±0.02[2] mas/yr
Dec.: −20.510±0.017[2] mas/yr
Parallax (π)7.7433 ± 0.0185[2] mas
Distance421 ± 1 ly
(129.1 ± 0.3 pc)
GI Tauri
Proper motion (μ) RA: 5.76±0.02 mas/yr
Dec.: −20.642±0.019 mas/yr
Parallax (π)7.7258 ± 0.0198[3] mas
Distance422 ± 1 ly
(129.4 ± 0.3 pc)
Position (relative to GK Tauri)[5]
ComponentGI Tauri
Angular distance13.15797±0.00005
Position angle328.4399±0.0002°
Observed separation
(projected)
1700 AU
Details[5]
GK Tauri
Mass0.79±0.07 M
Luminosity0.80[6] L
Temperature4007[6] K
Age2±1 Myr
GI Tauri
Mass0.53+0.09−0.11 M
Luminosity0.49[6] L
Temperature3792[6] K
Age2±1 Myr
Other designations
GK Tauri: Gaia EDR3 147790206908395776, 2MASS J04333456+2421058, GSC 01829-00040
GI Tauri: Gaia EDR3 147790000749072768, 2MASS J04333405+2421170, GSC 01829-00082
Database references
SIMBADdata

GK Tauri is a young T Tauri-type pre-main sequence star in the constellation of Taurus about 421 light years away, belonging to the Taurus Molecular Cloud.

System

The stars GK Tauri and GI Tauri form a wide binary system, with the projected separation between components being 1700 AU. The secondary component's orbit is not very eccentric, with a periastron of at least 890 AU.[5]

GK Tauri was originally believed to have a close stellar companion WDS J04336+2421Ab.[7] However, it was found to be an unrelated background star according to Gaia data.[8]

Properties

Both members of the binary system are medium-mass objects still contracting towards the main sequence and accreting mass, with the primary GK Tauri being close to entering the main sequence.[4][5]

Protoplanetary system

Both stars are surrounded by compact protoplanetary disks, although the reason for the small disk sizes is not clear.[5] GK Tauri's spectrum indicates a possible gap in the protoplanetary disk and a planet orbiting within the gap, with a semimajor axis of 2.4+1.5−1.0 AU.[4]

The GK Tauri planetary system[5]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
protoplanetary disk 0–19 AU 40.2+5.9−6.2°
The GI Tauri planetary system[5]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
protoplanetary disk 0–25 AU 43.8±1.1°

References

  1. Bouvier, J.; Cabrit, S.; Fernandez, M.; Martin, E. L.; Matthews, J. M. (May 1993). "COYOTES I : the photometric variability and rotational evolution of T Tauri stars". Astronomy and Astrophysics 272: 176–206. Bibcode1993A&A...272..176B. https://ui.adsabs.harvard.edu/abs/1993A&A...272..176B. Retrieved 31 March 2022. 
  2. 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. 3.0 3.1 3.2 3.3 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  4. 4.0 4.1 4.2 Marsh, Kenneth A.; Mahoney, Michael J. (1993), "Do the Spectral Energy Distributions of GK Tauri and HK Tauri Indicate the Presence of Planetary Companions?", The Astrophysical Journal 405: L71, doi:10.1086/186768, Bibcode1993ApJ...405L..71M 
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Pearce, Logan A.; Kraus, Adam L.; Dupuy, Trent J.; Mann, Andrew W.; Newton, Elisabeth R.; Tofflemire, Benjamin M.; Vanderburg, Andrew (2020), "Orbital Parameter Determination for Wide Stellar Binary Systems in the Age of Gaia", The Astrophysical Journal 894 (2): 115, doi:10.3847/1538-4357/ab8389, Bibcode2020ApJ...894..115P 
  6. 6.0 6.1 6.2 6.3 Braun, Teresa A. M.; Yen, Hsi-Wei; Koch, Patrick M.; Manara, Carlo F.; Miotello, Anna; Testi, Leonardo (2021), "Dynamical Stellar Masses of Pre-main-sequence Stars in Lupus and Taurus Obtained with ALMA Surveys in Comparison with Stellar Evolutionary Models", The Astrophysical Journal 908 (1): 46, doi:10.3847/1538-4357/abd24f, Bibcode2021ApJ...908...46B 
  7. "V* GK Tau". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+GK+Tau. 
  8. Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.