BP Tauri is a young T Tauri star in the constellation of Taurus about 416 light years away, belonging to the Taurus Molecular Cloud.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 19m 15.8343s[2] |
| Declination | +29° 06′ 26.9295″[2] |
| Apparent magnitude (V) | 12.12 |
| Characteristics | |
| Evolutionary stage | pre-main-sequence star |
| Spectral type | K5 |
| Apparent magnitude (G) | 11.460[3] |
| Variable type | T Tau |
| Astrometry | |
| Radial velocity (Rv) | 15.76±0.13 km/s |
| Proper motion (μ) | RA: 8.889[3] mas/yr Dec.: -26.011[3] mas/yr |
| Parallax (π) | 7.8494 ± 0.0362 mas[3] |
| Distance | 416 ± 2 ly (127.4 ± 0.6 pc) |
| Details | |
| Mass | 1.24+0.25 −0.32[4] M☉ |
| Radius | 2.0[5] R☉ |
| Luminosity | 0.93[5] L☉ |
| Surface gravity (log g) | 4.32±0.14[6] cgs |
| Temperature | 3640+94 −92[6] K |
| Rotational velocity (v sin i) | 11.4+0.25 −0.55[6] km/s |
| Age | 6±4[4] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Properties
BP Tauri is still accreting mass at the low rate of 9×10−10 M☉ and 1.6×10−7 M☉/year,[7] as evidenced by X-rays produced by infalling matter,[8] and may be still in the process of spin-up.[9] Its chromospheric magnetic fields are rather strong at 2.5+0.15
−0.16 kilogauss,[6] and contains strong non-dipole components.[10] The star is producing 40% of its luminosity via the energy released by accretion.[5]
Suspected companions
There were two suspected stellar companions to BP Tauri on projected separations 3.00 and 5.45 arcseconds.[11] These were proven to be a background stars not related to BP Tauri with Gaia data though.[12][13]
Protoplanetary system
The star is surrounded by a protoplanetary disk. The disk is strongly depleted in carbon and carbon monoxide.[14]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| protoplanetary disk | 0–120[15] AU | 30[14]° | — | |||
Variability
BP Tauri varies in brightness, producing a strong flares due to unsteady accretion[5] held by stellar magnetic field. The lightcurve period is variable from 6.1 to 7.6 days, and quiescent periods without variability are also known.[16]