η2 Pictoris, Latinised as Eta2 Pictoris, is a solitary[8] star in the southern constellation of Pictor. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.02.[2] With an annual parallax shift of 7.8 mas as seen from the Earth,[1] it is located around 418 light years from the Sun. It is a member of the HR 1614 moving group of stars that share a common motion through space.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Pictor |
| Right ascension | 05h 04m 58.01433s[1] |
| Declination | −49° 34′ 40.2034″[1] |
| Apparent magnitude (V) | 5.02[2] |
| Characteristics | |
| Spectral type | K5 III[3] |
| U−B color index | +1.82[2] |
| B−V color index | +1.51[2] |
| Variable type | suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | −5.0±7.4[5] km/s |
| Proper motion (μ) | RA: +68.538[1] mas/yr Dec.: −2.186[1] mas/yr |
| Parallax (π) | 7.8033 ± 0.1351 mas[1] |
| Distance | 418 ± 7 ly (128 ± 2 pc) |
| Absolute magnitude (MV) | −1.2[6] |
| Details | |
| Radius | 40.56+0.59 −2.38[1] R☉ |
| Luminosity | 362.6±7.4[1] L☉ |
| Temperature | 3,955+121 −28[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved K-type giant star with a stellar classification of K5 III,[3] having exhausted the supply of hydrogen at its core, then cooled and expanded off the main sequence. At present it has 41[1] times the girth of the Sun. It is radiating an estimated 363.5 times the Sun's luminosity from its photosphere at an effective temperature of 4,136 K.[9] This is a member of the old disk population and is a suspected variable star.[10]
References edit
- ^ a b c d e f g h i j Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Cousins, A. W. J.; et al. (1969), "Comparison Stars for Long Period Variables", Monthly Notes of the Astronomical Society of Southern Africa, 28: 63, Bibcode:1969MNSSA..28...63C.
- ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Department of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ 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: B/gcvs. Bibcode:2009yCat....102025S.
- ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b Eggen, Olin J. (October 1996), "Star Streams and Galactic Structure", Astronomical Journal, 112: 1595, Bibcode:1996AJ....112.1595E, doi:10.1086/118126.
- ^ "* eta02 Pic". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-22.
{{cite web}}: CS1 maint: postscript (link) - ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ Eggen, O. J. (1973), "The classification of intrinsic variables. IV. Very-small-amplitude, very-short-period red variables", Astrophysical Journal, 184: 793, Bibcode:1973ApJ...184..793E, doi:10.1086/152371.