SU Aurigae

SU Aurigae is a T Tauri-type variable star in the constellation Auriga. It is located about 500 light-years (150 parsecs) away in the Taurus-Auriga Star Forming Region. Its apparent magnitude is 9.30, which is dim enough that it cannot be seen with the unaided eye.

SU Aurigae

Diagram of SU Aurigae's magnetic field
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension  04h 55m 59.38527s[1]
Declination +30° 34′ 01.5190″[1]
Apparent magnitude (V) 9.30[2]
Characteristics
Spectral type G2IIIne[2]
B−V color index +0.74[3]
Variable type T Tauri
Astrometry
Radial velocity (Rv)23.20[4] km/s
Proper motion (μ) RA: 1.18[1] mas/yr
Dec.: -22.24[1] mas/yr
Parallax (π)6.85 ± 2.23[1] mas
Distanceapprox. 500 ly
(approx. 150 pc)
Absolute magnitude (MV)+2.83[3]
Details[3]
Mass2.0±0.1 M☉
Radius2.61+0.20
−0.23 R☉
Luminosity6.3±1.6 L☉
Surface gravity (log g)3.91+0.07
−0.10 cgs
Temperature5550±100 K
Rotation1.76+0.29
−0.33
Rotational velocity (v sin i)66.2 km/s
Age4 Myr
Other designations
SU Aur, BD+30° 743, HD 282624, HIP 22925, SAO 57509
Database references
SIMBADdata

SU Aurigae's spectral type of G2IIIne means that it is a G-type star with an effective temperature similar to the Sun. The III in the spectral type refers to its luminosity, which is much higher than normal G-type main sequence stars and would put it in the giant star class.[5] However, it is only about 4 million years old, which is relatively young for a star - young protostars like SU Aurigae are luminous because they are larger, not condensing into a normal size until they are older.[6]

SU Aurigae is known to have a circumstellar protoplanetary disk surrounding it, which is typical of many T Tauri stars.[6] SU Aurigae's disk has a high inclination of 62° and is nearly perpendicular to the plane of sky, so orbiting protoplanets or comets may be the cause of why there are drops in the amount of light detected.[3] SU Aurigae's proper motion and distance is similar to AB Aurigae,[1] a better known pre-main-sequence star, meaning that the two may form a very wide binary system;[5] if not, they are still in the same star association.

References
  1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. "SU Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 17 January 2016.
  3. DeWarf, L. E.; Sepinsky, J. F.; Guinan, E. F.; Ribas, I.; Nadalin, I. (2003). "Intrinsic Properties of the Young Stellar Object SU Aurigae". The Astrophysical Journal. 590 (1): 357–367. Bibcode:2003ApJ...590..357D. CiteSeerX 10.1.1.508.2455. doi:10.1086/374979.
  4. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  5. "AB Aurigae - Jim Kaler". 4 January 2013. Retrieved 17 January 2017.
  6. "Encyclopedia of Science: T Tauri star". Retrieved 17 January 2017.
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