Alpha Pavonis
 Location of α Pavonis (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Pavo |
| Right ascension | 20h 25m 38.85705s[1] |
| Declination | −56° 44′ 06.3230″[1] |
| Apparent magnitude (V) | 1.94[2] |
| Characteristics | |
| Spectral type | B2 IV[3] |
| U−B color index | −0.71[2] |
| B−V color index | −0.20[2] |
| Astrometry | |
| Radial velocity (Rv) | +2.0[4] km/s |
| Proper motion (μ) | RA: 6.90[1] mas/yr Dec.: −86.02[1] mas/yr |
| Parallax (π) | 18.24 ± 0.52[1] mas |
| Distance | 179 ± 5 ly (55 ± 2 pc) |
| Details | |
| Mass | 6.3 ± 0.2[5] M☉ |
| Radius | 4.5–5.6[6] R☉ |
| Luminosity | 2,200[5] L☉ |
| Surface gravity (log g) | 3.8[7] |
| Temperature | 18,000[7] K |
| Rotational velocity (v sin i) | 39[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Alpha Pavonis (α Pav) is a star in the southern constellation Pavo, near the shared border with the Telescopium constellation. It is also known by the name Peacock, which was assigned by Her Majesty's Nautical Almanac Office in the late 1930s during the creation of the Air Almanac, a navigational almanac for the Royal Air Force. Of the fifty-seven stars included in the new almanac, two had no classical names: Epsilon Carinae and Alpha Pavonis. The RAF insisted that all of the stars must have names, so new names were invented. Alpha Pavonis was named "Peacock" ('pavo' is Latin for 'peacock') whilst Epsilon Carinae was called "Avior".[8]
At an apparent magnitude of 1.94, this is the brightest star in Pavo. Based upon parallax measurements, this star is about 179 light year distant from the Earth. It has an estimated six times the Sun's mass and 5–6 times the Sun's radius,[6] but 2,200 times the luminosity of the Sun.[5] The effective temperature of the photosphere is 18,000 K,[7] which gives the star a blue-white hue.[9] A stellar classification of B2 IV suggests it is a subgiant star that has begun to evolve from the main sequence with the exhaustion of the hydrogen at its core.
Alpha Pavonis is a spectroscopic binary consisting of a pair of stars that orbit around each other with a period of 11.753 days.[7] However, in part because the two stars have not been individually resolved, little is known about the companion. The system may be a member of the Tucana-Horologium association of stars that share a common motion through space.[10] The estimated age of this association is 30 million years, which, as the members share a common origin, suggests a similar age for Alpha Pavonis.[11]
[edit] Notes
- ^ a b c d e van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. Bibcode 2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- ^ a b c 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
- ^ a b "PEACOCK -- Spectroscopic binary", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Alpha+Pavonis, retrieved 2011-12-23
- ^ Wilson, Ralph Elmer (1953), General catalogue of stellar radial velocities, Carnegie Institution of Washington, Bibcode 1953QB901.W495.....
- ^ a b c Jerzykiewicz, M.; Molenda-Zakowicz, J. (September 2000), "Empirical Luminosities and Radii of Early-Type Stars after Hipparcos", Acta Astronomica 50: 369–380, Bibcode 2000AcA....50..369J
- ^ a b 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: 521–524, Bibcode 2001A&A...367..521P, doi:10.1051/0004-6361:20000451
- ^ a b c d e Vidal-Madjar, A. et al. (August 1988), "Deuterium in early-type stars - The case of Alpha-Pavonis", Astronomy and Astrophysics 201 (2): 273–275, Bibcode 1988A&A...201..273V
- ^ Sadler, D. H. (1993), A Personal History of H.M. Nautical Almanac Office, Edited and privately published by Wilkins, G. A., p. 46
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16
- ^ Zuckerman, B.; Song, Inseok; Webb, R. A. (September 2001), "Tucana Association", The Astrophysical Journal 559 (1): 388–394, Bibcode 2001ApJ...559..388Z, doi:10.1086/322305
- ^ da Silva, L. et al. (December 2009), "Search for associations containing young stars (SACY). III. Ages and Li abundances", Astronomy and Astrophysics 508 (2): 833–839, Bibcode 2009A&A...508..833D, doi:10.1051/0004-6361/200911736
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