Z Chamaeleontis

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Z Chamaeleontis
ZChaLightCurve.png
A light curve for Z Chamaeleontis, adapted from Wood et al. (1986) [1]
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
Primarywhite dwarf
Companionred 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]

Contents

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

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.

Possible makeup of the Z Chamaeleontis Star system. Diagram of the (possible) Z Chamaeleontis Star system.png
Possible makeup of the Z Chamaeleontis Star system.
The Z Chamaeleontis planetary system [9]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(years)		 Eccentricity Inclination Radius
b(unconfirmed)≥20 MJ 9.928≤0.2——

See also

References

  1. ↑ 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 .
  2. ↑ 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.
  3. ↑ 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.
  4. ↑ 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.
  5. ↑ 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.
  6. 1 2 3 4 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 .
  7. 1 2 3 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.
  8. 1 2 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.
  9. 1 2 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 .
  10. ↑ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C . Retrieved 26 January 2025.
  11. ↑ Mumford, G. S. (March 1969). "Z Chameleontis" (PDF). Information Bulletin on Variable Stars. 337: 1. Bibcode:1969IBVS..337....1M . Retrieved 26 January 2025.


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