RY Tauri
Star in the constellation Taurus
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RY Tauri is a young T Tauri star in the constellation of Taurus about 450 light years away, belonging to the Taurus Molecular Cloud. It is more massive than typical T Tauri stars, and may be an intermediate between this class and the Herbig Ae/Be star type.[9]
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| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Taurus[1] |
| Right ascension | 04h 21m 57.4133s[citation needed] |
| Declination | +28° 26′ 35.534″[citation needed] |
| Apparent magnitude (V) | 9.5 - 11.5[2] |
| Characteristics | |
| Evolutionary stage | pre-main-sequence star |
| Spectral type | F7[3] |
| Apparent magnitude (G) | 10.706[4] |
| Variable type | T Tau[5] |
| Astrometry | |
| Radial velocity (Rv) | 24.3±1.9 km/s |
| Proper motion (μ) | RA: 8.744[4] mas/yr Dec.: −27.002[4] mas/yr |
| Parallax (π) | 7.2349±0.2031 mas[4] |
| Distance | 450 ± 10 ly (138 ± 4 pc) |
| Absolute magnitude (MV) | +2.11 (at magnitude 9.55)[2] |
| Position (relative to RY Tauri)[6] | |
| Component | 2MASS J04215810+2826300 |
| Angular distance | 10.83″ |
| Position angle | 122.41° |
| Projected separation | 1500 AU |
| Details | |
| Mass | 1.95+0.10 −0.17[7] M☉ |
| Radius | 3.2[8] R☉ |
| Luminosity | 11.6[8] L☉ |
| Surface gravity (log g) | 3.70±0.21[7] cgs |
| Temperature | 5,495±143[7] K |
| Metallicity [Fe/H] | 0.32±0.28[7] dex |
| Rotation | 2.97+0.88 −0.55[7] days |
| Rotational velocity (v sin i) | 50±2[7] km/s |
| Age | 4.29+1.43 −0.89[7] Myr |
| Other designations | |
| BD+28 645, HD 283571, HIP 20387, TYC 1828-129-1, GSC 01828-00129, 2MASS J04215740+2826355, Gaia DR2 164551162164119424 | |
| Database references | |
| SIMBAD | data |
Stellar system
Protoplanetary system
The star is surrounded by a protoplanetary disk discovered in 2006.[9] The disk is massive at 0.3M☉ and consists mostly of gas.[11] The existence of a protoplanetary disk is disputed; the signal can also be attributed to the birth envelope partially disrupted by the young star. Also, polar jets were detected.[12] The jets contain detectable amounts of oxygen and sulfur.[3] A superjovian planet on a 0.2 AU orbit is suspected since 2021.[13]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| protoplanetary disk | 0.21–80 AU | 65° | — | |||
Variability
Henrietta Swan Leavitt's discovery that RY Tauri is a variable star was reported in 1907.[17] It is a highly (by 1.5 magnitudes)[12] obscured Orion variable, producing fluctuations of brightness as the star shines through the inhomogeneities of the inner part of the protoplanetary disk.[11] It also produces irregular brightening events with a duration of about a month and amplitude of one magnitude.[18] The light curve of RY Tauri varies by 2-3 magnitudes over a decade and by roughly one magnitude over a year. The star was gradually brightening during the 20th century, possibly changing the variability mechanism in the process.[19]