Z Chamaeleontis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Chamaeleon |
| Right ascension | 08h 07m 27.7517s |
| Declination | −76° 32′ 00.6650″ |
| Apparent magnitude (V) | 11.5 - 16.2[2] |
| Characteristics | |
| Spectral type | DA? + M5.5e[3] |
| Variable type | SU UMa + Algol[4] |
| Astrometry | |
| Radial velocity (Rv) | −20[5] km/s |
| Proper motion (μ) | RA: −33.650 mas/yr[6] Dec.: +56.883 mas/yr[6] |
| Parallax (π) | 8.2805±0.074 mas[6] |
| Distance | 394 ± 4 ly (121 ± 1 pc) |
| Orbit | |
| Primary | white dwarf |
| Companion | red dwarf |
| Period (P) | 1.79 h[7] |
| Eccentricity (e) | 0[7] |
| Inclination (i) | 81.8±0.1[8]° |
| Semi-amplitude (K1) (primary) | 105[7] km/s |
| Details | |
| white dwarf | |
| Mass | 1[8] M☉ |
| Radius | 0.013/0.48 R☉ |
| Luminosity | 0.007/0.017 L☉ |
| Temperature | 14,700/3100 K |
| red dwarf | |
| 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 |
Z Chamaeleontis (abbreviated Z Cha) is a dwarf nova variable star system approximately 394 light-years[6] 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.[9]
Z Chamaeleontis was discovered in 1904, during the work required to produce the Astrographic Catalogue. By 1905 a period of variability had been derived.[10] in 1969, George S. Mumford discovered that in addition to being a dwarf nova, the star is an eclipsing variable.[11]
Substellar companion
[edit | edit source]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){kind=link}
| 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
[edit | edit source]References
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- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). (Erratum: Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).). Gaia EDR3 record for this source at VizieR.
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