XZ Tauri
Star in the constellation Taurus
From Wikipedia, the free encyclopedia
XZ Tauri is a binary system approximately 460 light-years away in the constellation Taurus. The system consists of two T Tauri stars orbiting each other about 6 billion kilometers apart (roughly the same distance as Pluto is from the Sun). The system made news in 2000 when a superflare was observed in the system.
A visual band light curve for XZ Tauri. The main plot shows the long-term variability, and the inset shows the year 2000 superflare on the north star. Adapted from Dodin et al. (2016)[1] and Coffey et al. (2004).[2] | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 31m 40.08690s[3] |
| Declination | +18° 13′ 56.6424″[3] |
| Apparent magnitude (V) | 10.40[4] |
| Characteristics | |
| Spectral type | M2.0 + M3.5[5] |
| Astrometry | |
| Proper motion (μ) | RA: 9.1[6] mas/yr Dec.: −17.8[6] mas/yr |
| Distance | 460 ly (140[7] pc) |
| Orbit[8] | |
| Primary | A[a] |
| Name | B |
| Period (P) | 155 yr |
| Semi-major axis (a) | 0.172+0.002 −0.003″ |
| Eccentricity (e) | 0.742+0.025 −0.034 |
| Inclination (i) | 0.0° |
| Argument of periastron (ω) (secondary) | −42.2+2.0 −4.7° |
| Details[5] | |
| A[a] | |
| Mass | 0.37 M☉ |
| Radius | 1.1 R☉ |
| Luminosity | 0.17 L☉ |
| B | |
| Mass | 0.29 M☉ |
| Radius | 1.7 R☉ |
| Luminosity | 0.31 L☉ |
| Temperature | 3,550[7] K |
| Age | 4.6[7] Myr |
| Other designations | |
| XZ Tau, GSC 01269-00171[9] | |
| Database references | |
| SIMBAD | data |
A third star, component C, has been observed at a separation of 0.09″, but subsequent observations failed to find it.[10][8] The T Tauri star HL Tauri, 23″ away, is also sometimes listed as a companion.[9]
The discovery by Pelageya Fedorovna Shajn, that XZ Tauri is a variable star, was announced in 1928.[11]
Gallery
Notes
- Sources vary on their definitions of the primary and secondary components. A is defined here as the more massive component, with a lower temperature but higher luminosity. Other sources refer to the components as north and south,[2] or Aa and Ab.[9] The southerly star Ab is generally brighter at optical wavelengths and more massive, but is less luminous.