Chi Aquarii
| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 23h 16m 50.93916s[1] |
| Declination | −07° 43′ 35.4023″[1] |
| Apparent magnitude (V) | +5.06[2] |
| Characteristics | |
| Spectral type | M3 III[3] |
| U−B color index | +1.60[2] |
| B−V color index | +1.60[2] |
| Variable type | SRb?[4] |
| Astrometry | |
| Radial velocity (Rv) | –13.72 ± 0.86[5] km/s |
| Proper motion (μ) | RA: −19.18[1] mas/yr Dec.: −14.10[1] mas/yr |
| Parallax (π) | 5.32 ± 0.37[1] mas |
| Distance | 610 ± 40 ly (190 ± 10 pc) |
| Details | |
| Radius | 137[6] R☉ |
| Other designations | |
| Data sources: | |
| Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) | |
Chi Aquarii (χ Aqr, χ Aquarii) is the Bayer designation of a star in the equatorial constellation of Aquarius. The distance to this star, based upon parallax measurements with a 7% margin of error, is roughly 610 light-years (190 parsecs).[1] It is visible to the naked eye with an apparent visual magnitude of +5.06.[2]
This is a red giant star with a spectral classification of M3 III.[3] The interferometry-measured angular diameter of this star is 6.70 ± 0.15 mas,[8] which, at its estimated distance, equates to a physical radius of about 137 times the radius of the Sun.[6] It is classified as a semi-regular variable star and its brightness varies by an amplitude of 0.0636 in magnitude.[9] The identified pulsation periods are 32.3, 38.5, and 44.9 days.[10]
References
- 1 2 3 4 5 6 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752
, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. - 1 2 3 4 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
- 1 2 Crampton, D.; Lloyd Evans, T. (1973), "Spectroscopic observations of M giant stars at the South Galactic Pole", Monthly Notices of the Royal Astronomical Society, 162: 11–15, Bibcode:1973MNRAS.162...11C, doi:10.1093/mnras/162.1.11.
- ↑ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- ↑ Famaey, B.; et al. (May 2009), "Spectroscopic binaries among Hipparcos M giants. I. Data, orbits, and intrinsic variations", Astronomy and Astrophysics, 498 (2): 627–640, arXiv:0901.0934, Bibcode:2009A&A...498..627F, doi:10.1051/0004-6361/200810698.
- 1 2 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
- ↑ "chi Aqr -- Semi-regular pulsating Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-05.
- ↑ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
- ↑ Koen, Chris; Eyer, Laurent (March 2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331 (1): 45–59, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x.
- ↑ Tabur, V.; et al. (December 2009), "Long-term photometry and periods for 261 nearby pulsating M giants", Monthly Notices of the Royal Astronomical Society, 400 (4): 1945–1961, arXiv:0908.3228, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x.
