Astronomy:Delta2 Chamaeleontis
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Chamaeleon[1] |
| Right ascension | 10h 45m 47.00487s[2] |
| Declination | −80° 32′ 24.6785″[2] |
| Apparent magnitude (V) | 4.42[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | B3 V[4] or B2.5 IV[5] |
| U−B color index | −0.728[3] |
| B−V color index | −0.192[3] |
| Variable type | β Cep+SPB[6] |
| Astrometry | |
| Radial velocity (Rv) | +22.6[7] km/s |
| Proper motion (μ) | RA: −36.917[2] mas/yr Dec.: +6.327[2] mas/yr |
| Parallax (π) | 8.7273 ± 0.1058[2] mas |
| Distance | 374 ± 5 ly (115 ± 1 pc) |
| Absolute magnitude (MV) | −0.71[1] |
| Details | |
| Mass | 5.0±0.1[8] M☉ |
| Radius | 3.9[9] R☉ |
| Luminosity | 1,072[6] L☉ |
| Temperature | 18,363[6] K |
| Rotational velocity (v sin i) | 55[6] km/s |
| Age | 32.6±16.3[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Delta2 Chamaeleontis is a solitary[11] star located in the southern circumpolar constellation of Chamaeleon. Its name is a Bayer designation that is Latinized from δ2 Chamaeleontis, and abbreviated Delta2 Cha or δ2 Cha. This star has an apparent visual magnitude of 4.42,[3] which is bright enough it to be viewed with the naked eye. Based upon an annual parallax shift of 8.73 mas,[2] it is located at a distance of around 374 light-years (115 pc) 351 light years from the Sun. The star is drifting further away with a line of sight velocity component of +23 km/s.[7]
This star is one of two systems named Delta Chamaeleontis, the other being the fainter Delta1 Chamaeleontis located about 6 arcminutes away.[12] Delta Chamaeleontis forms the southernmost component of the constellation's "dipper" or bowl. Together with Gamma Chamaeleontis, they point to a spot that is within 2° of the south celestial pole.[13]
Delta2 Chamaeleontis is a B-type main sequence star with a stellar classification of B3 V.[4] However, Hiltner et al. (1969) give a classification of B2.5 IV,[5] which would suggest it is a more evolved subgiant star. Based on data from the TESS space telescope, it is a pulsating star that displays characteristics of a Beta Cephei variable, a slowly pulsating B-type star, and a rotating variable.[6]
It is estimated to have five[8] times the mass of the Sun and 3.9[9] times the Sun's radius. With an age of 32.6[8] million years, it has a high rate of spin, showing a projected rotational velocity of 55 km/s. It is radiating over 1,000 times the solar luminosity from its outer atmosphere at an effective temperature of 18,363 K.[6] There is a 70% likelihood that this star is a member of Gould's Belt.[14]
References
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940. Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement Series 15: 459, doi:10.1086/190168, Bibcode: 1968ApJS...15..459G.
- ↑ 4.0 4.1 Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode: 1978mcts.book.....H.
- ↑ 5.0 5.1 Hiltner, W. A. et al. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal 157: 313, doi:10.1086/150069, Bibcode: 1969ApJ...157..313H.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Balona, L. A.; Ozuyar, D. (2020), "Pulsation among TESS a and B stars and the Maia variables", Monthly Notices of the Royal Astronomical Society 493 (4): 5871, doi:10.1093/mnras/staa670, Bibcode: 2020MNRAS.493.5871B.
- ↑ 7.0 7.1 Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, 30, University of Toronto: International Astronomical Union, p. 57, Bibcode: 1967IAUS...30...57E.
- ↑ 8.0 8.1 8.2 8.3 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ 9.0 9.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics", Astronomy and Astrophysics 367 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ "del02 Cha". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del02+Cha.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Inglis, Michael (2012), Astronomy of the Milky Way: The Observer's Guide to the Southern Milky Way, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media, p. 106, ISBN 978-1447106418, https://books.google.com/books?id=Gu4GCAAAQBAJ&pg=PA106.
- ↑ O'Meara, Stephen James (2002), Deep-Sky Companions: The Caldwell Objects, Cambridge University Press, p. 424, ISBN 0521827965, https://books.google.com/books?id=3Hg6YHgx9nAC&pg=PA427.
- ↑ Bobylev, V. V.; Bajkova, A. T. (September 2007), "Kinematics of the Scorpius-Centaurus OB association", Astronomy Letters 33 (9): 571–583, doi:10.1134/S1063773707090010, Bibcode: 2007AstL...33..571B.
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