TW Pictoris
TW Pictoris is a 14th magnitude cataclysmic variable star system in the southern constellation of Pictor. It is located at a distance of approximately 1,430 light-years based on parallax measurements. Photometric observations in the visual band suggest a binary system with an orbital period of 6.06 hours. One of the components is an accreting white dwarf.
A light curve for TW Pictoris. The main plot,adapted from Scaringi et al. (2021), shows the long-term visual band variation, and the inset plot, adapted from Patterson and Moulden (1993), shows the periodic variability. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pictor |
| Right ascension | 05h 34m 50.586s |
| Declination | −58° 01′ 40.77″ |
| Apparent magnitude (V) | 15.10 (14.1 - 15.6) |
| Characteristics | |
| U−B color index | 0.99 |
| B−V color index | 0.27 |
| Variable type | Nova-like variable |
| Astrometry | |
| Proper motion (μ) | RA: −11.632 mas/yr Dec.: 3.745 mas/yr |
| Parallax (π) | 2.2839 ± 0.0223 mas |
| Distance | 1,430 ± 10 ly (438 ± 4 pc) |
| Other designations | |
TW Pic, H0534-581 | |
| Database references | |
| SIMBAD | data |
The X-ray source H0534-581 was identified from the data collected by the HEAO 1 satellite in 1979. In 1984, a candidate optical counterpart was identified by I. R. Tuohy and associates from photographs taken at the Schmidt telescope. A low-resolution spectrum revealed this is a cataclysmic variable, and it was assigned the variable star designation TW Pictoris. It was initially proposed to be an intermediate polar, but the lack of an X-ray pulsation makes this less likely. The current classification remains controversial.