Z Chamaeleontis
Z Chamaeleontis (abbreviated Z Cha) is a dwarf nova variable star system approximately 377 light-years away from the Sun, where two stars orbit each other every 1.78 hours. The system comprises an eclipsing white dwarf and red dwarf and possibly a yet unconfirmed third low-mass substellar companion.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Chamaeleon |
| Right ascension | 08h 07m 27.7422s[1] |
| Declination | −76° 32′ 00.6796″[1] |
| Apparent magnitude (V) | +13.0 |
| Characteristics | |
| Spectral type | DA / M6V |
| Astrometry | |
| Proper motion (μ) | RA: −33.650±0.222[1] mas/yr Dec.: 56.883±0.239[1] mas/yr |
| Parallax (π) | 8.6625 ± 0.1235[1] mas |
| Distance | 377 ± 5 ly (115 ± 2 pc) |
| Details | |
| Mass | 0.7/0.12 M☉ |
| Radius | 0.013/0.48 R☉ |
| Luminosity | 0.007/0.017 L☉ |
| Temperature | 14,700/3100 K |
| Orbit | |
| Period (P) | 0.0002 yr |
| Semi-major axis (a) | 0.003 AU |
| Inclination (i) | 81.7° |
| Other designations | |
Z Cha, 2E 1942, SBC9 505, CSV 1244, 2MASS J08072774-7632006, SON 4893, 2E 0808.8-7622, 1RXS J080728.8-763157, AAVSO 0809-76 | |
| Database references | |
| SIMBAD | data |
Substellar companion
Dai et al. (2009) invoke the presence of a third object to explain orbital period variations with an apparent periodicity of roughly 28 years. The third body could yield a minimum mass 20 times greater than Jupiter and be located 9.9 Astronomical Units away from the dwarf nova, being likely a low-mass brown dwarf.
_Z_Chamaeleontis_Star_system.png.webp)
Possible makeup of the Z Chamaeleontis Star system.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | ≥20 MJ | 9.9 | 28 | ≤0.2 | — | — |
See also
References
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- Dai; Qian, Shengbang; Lajús, Eduardo FernáNdez (26 August 2009). "Evidence of a Brown Dwarf in the Eclipsing Dwarf Nova Z Chamaeleonis". The Astrophysical Journal. 703 (1): 109–113. Bibcode:2009ApJ...703..109D. doi:10.1088/0004-637X/703/1/109.
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