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]
| 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 d[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 |
Substellar companion
editDai 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)
| 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
editReferences
edit- ^ Wood, Janet; Horne, Keith; Berriman, Graham; Wade, R.; O'Donoghue, D.; Warner, B. (April 1986). "High-speed photometry of the dwarf nova Z Cha in quiescence". Monthly Notices of the Royal Astronomical Society. 219 (3): 629–655. Bibcode:1986MNRAS.219..629W. doi:10.1093/mnras/219.3.629.
- ^ Watson, C. L.; Henden, A. A.; Price, A. (May 2006). "The International Variable Star Index (VSX)". Society for Astronomical Sciences Annual Symposium. 25: 47. Bibcode:2006SASS...25...47W.
- ^ Wade, Richard A.; Horne, Keith (January 1988). "The radial velocity curve and peculiar TiO distribution of the red secondary star in Z Chamaeleontis". The Astrophysical Journal. 324: 411. Bibcode:1988ApJ...324..411W. doi:10.1086/165905. eISSN 1538-4357. ISSN 0004-637X.
- ^ Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. ISSN 1063-7729. S2CID 255195566.
- ^ Duflot, M.; Figon, P.; Meyssonnier, N. (December 1995). "Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue". Astronomy and Astrophysics Supplement Series. 114: 269. Bibcode:1995A&AS..114..269D. ISSN 0365-0138.
- ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c Marsh, T. R.; Horne, Keith; Shipman, H. L. (April 1987). "A spectrophotometric study of the emission lines in the quiescent dwarf nova Z Chamaeleontis". Monthly Notices of the Royal Astronomical Society. 225 (3): 551–580. Bibcode:1988ApJ...324..411W. doi:10.1093/mnras/225.3.551. eISSN 1365-2966. ISSN 0035-8711.
- ^ a b Otulakowska-Hypka, Magdalena; Olech, Arkadiusz; Patterson, Joseph (12 May 2016). "Statistical analysis of properties of dwarf novae outbursts". Monthly Notices of the Royal Astronomical Society. 460 (3): 2526–2541. arXiv:1605.02937. Bibcode:2016MNRAS.460.2526O. doi:10.1093/mnras/stw1120. eISSN 1365-2966. ISSN 0035-8711.
- ^ a b 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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