Eta2 Pictoris
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Pictor |
| Right ascension | 05h 04m 58.01453s[1] |
| Declination | −49° 34′ 40.2079″[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] |
| Astrometry | |
| Radial velocity (Rv) | −5.0±7.4[4] km/s |
| Proper motion (μ) | RA: +68.96[1] mas/yr Dec.: −2.20[1] mas/yr |
| Parallax (π) | 7.35 ± 0.17[1] mas |
| Distance | 440 ± 10 ly (136 ± 3 pc) |
| Absolute magnitude (MV) | −1.2[5] |
| Details | |
| Radius | 40.6[6] R☉ |
| Luminosity | 363.50[7] L☉ |
| Temperature | 4,136[7] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
η2 Pictoris, Latinised as Eta2 Pictoris, is a solitary,[9] orange-hued star in the southern constellation of Pictor. It is visible to the naked eye with an apparent visual magnitude of 5.02.[2] With an annual parallax shift of 7.35[1] mas as seen from the Earth, it is located around 440 light years from the Sun. It is a member of the HR 1614 moving group of stars that share a common motion through space.[5]
This is an evolved K-type giant star with a stellar classification of K5 III.[3] The angular diameter of this star, after compensating for limb darkening is 2.774±0.063 mas.[10] At its estimated distance, this yields a physical size of about 40.6 times the radius of the Sun.[6] It is radiating an estimated 363.5 times the Sun's luminosity from its photosphere at an effective temperature of 4,136 K.[7] This is a member of the old disk population and is a suspected variable star.[11]
References
- 1 2 3 4 5 6 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752
, doi:10.1051/0004-6361:20078357. - 1 2 3 4 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.
- 1 2 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 2, Ann Arbor: Department of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ↑ 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, Bibcode:2012A&A...546A..61D, arXiv:1208.3048 , doi:10.1051/0004-6361/201219219, A61.
- 1 2 Eggen, Olin J. (October 1996), "Star Streams and Galactic Structure", Astronomical Journal, 112: 1595, Bibcode:1996AJ....112.1595E, doi:10.1086/118126.
- 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:
- 1 2 3 McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, Bibcode:2012MNRAS.427..343M, arXiv:1208.2037 , doi:10.1111/j.1365-2966.2012.21873.x.
- ↑ "eta02 Pic -- Variable Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-06-22.
- ↑ 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, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878 , doi:10.1111/j.1365-2966.2008.13596.x.
- ↑ Richichi, A.; et al. (October 2009), "A list of bright interferometric calibrators measured at the European Southern Observatory Very Large Telescope Interferometer", Monthly Notices of the Royal Astronomical Society, 399 (1): 399−409, Bibcode:2009MNRAS.399..399R, arXiv:0906.3981 , doi:10.1111/j.1365-2966.2009.15289.x.
- ↑ 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.
