Nu Pictoris
ν Pictoris, Latinized as Nu Pictoris, is a binary star system in the southern Pictor constellation. It is visible to the naked eye as a dim point of light with an apparent visual magnitude of 5.60.[2] The system is located around 157 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +7 km/s.[2]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pictor |
| Right ascension | 06h 22m 55.82671s[1] |
| Declination | −56° 22′ 11.8909″[1] |
| Apparent magnitude (V) | 5.60[2] |
| Characteristics | |
| Spectral type | A1mA3-A9[3] |
| U−B color index | 0.12[4] |
| B−V color index | 0.26[4] |
| Astrometry | |
| Radial velocity (Rv) | +6.7±2.9[2] km/s |
| Proper motion (μ) | RA: −39.96[1] mas/yr Dec.: −20.13[1] mas/yr |
| Parallax (π) | 20.72 ± 0.56[1] mas |
| Distance | 157 ± 4 ly (48 ± 1 pc) |
| Absolute magnitude (MV) | +2.18[2] |
| Orbit[5] | |
| Period (P) | 452+13 −16 d |
| Semi-major axis (a) | 5.9+1.6 −0.9 mas |
| Eccentricity (e) | 0.20+0.35 −0.19 |
| Inclination (i) | 116+12 −10° |
| Longitude of the node (Ω) | 53+166 −16° |
| Periastron epoch (T) | 2448660 |
| Argument of periastron (ω) (secondary) | 109±53° |
| Details | |
| Radius | 2.19+0.12 −0.10[6] R☉ |
| Luminosity | 15.4±0.4[6] L☉ |
| Temperature | 7,733+170 −203[6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Hipparcos satellite astrometry showed that ν Pictoris moved in a way that was not consistent with the proper motion and annual parallax of a single star. The unusual measurements were not readily identifiable as being due to orbital motion, and it was referred to as having a stochastic solution to its astrometry. Later analysis derived an orbit, although nothing is known about the companion except its approximate mass and motion about the visible star.[5]
The pair orbit each other with a period of 452 days and an eccentricity of 0.2.[5] The primary, component A, is a metal-lined Am star with a stellar classification of A1mA3-A9.[3] It has 2.2 times the radius of the Sun and is radiating 15 times the Sun's luminosity from its photosphere at an effective temperature of 7,733 K.[6] The secondary, component B, has around one fourth the mass of the primary.[8][5] The system is a source for X-ray emission, which is most likely coming from the companion.[9]
References
- van Leeuwen, F. (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. Vizier catalog entry
- Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
- Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. 1. Ann Arbor: Dept. of Astronomy, University of Michigan. Bibcode:1975mcts.book.....H.
- Feinstein, A. (1974). "Photoelectric UBVRI observations of AM stars". Astronomical Journal. 79: 1290. Bibcode:1974AJ.....79.1290F. doi:10.1086/111675.
- Goldin, A. (2007). "Astrometric Orbits for Hipparcos Stochastic Binaries". The Astrophysical Journal Supplement Series. 173 (1): 137–142. arXiv:0706.0361. Bibcode:2007ApJS..173..137G. doi:10.1086/520513.
- 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.
- "nu. Pic". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 December 2016.
- Goldin, A.; Makarov, V. V. (September 2006). "Unconstrained Astrometric Orbits for Hipparcos Stars with Stochastic Solutions". The Astrophysical Journal Supplement Series. 166 (1): 341–350. arXiv:astro-ph/0606293. Bibcode:2006ApJS..166..341G. doi:10.1086/505939.
- Schröder, C.; Schmitt, J. H. M. M. (November 2007). "X-ray emission from A-type stars". Astronomy and Astrophysics. 475 (2): 677–684. Bibcode:2007A&A...475..677S. doi:10.1051/0004-6361:20077429.