Summary
p Eridani is a binary star system in the constellation of Eridanus (the River) whose distance from the Sun is 26.7 light-years based upon parallax. It was found to be a double star in December 1825 by James Dunlop in Australia at his home at Paramatta, now spelt Parramatta. It is visible to the naked eye as a dim, orange-hued star. The system is moving further from the Earth with a heliocentric radial velocity of about +20 km/s.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Eridanus |
| A | |
| Right ascension | 01h 39m 47.813s[1] |
| Declination | −56° 11′ 35.94″[1] |
| Apparent magnitude (V) | 5.76[2] |
| B | |
| Right ascension | 01h 39m 47.565s[3] |
| Declination | −56° 11′ 47.21″[3] |
| Apparent magnitude (V) | 5.87[2] |
| Characteristics | |
| Spectral type | K2V + K2V[4] |
| U−B color index | +0.59 / +0.53[2] |
| B−V color index | +0.90 / +0.87[2] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +21.74±0.12[1] km/s |
| Proper motion (μ) | RA: 262.615[1] mas/yr Dec.: 14.961[1] mas/yr |
| Parallax (π) | 122.1088 ± 0.0365 mas[1] |
| Distance | 26.710 ± 0.008 ly (8.189 ± 0.002 pc) |
| Absolute magnitude (MV) | 6.25[5] |
| B | |
| Radial velocity (Rv) | +20.15±0.12[3] km/s |
| Proper motion (μ) | RA: 309.230[3] mas/yr Dec.: 10.815[3] mas/yr |
| Parallax (π) | 122.0035 ± 0.0319 mas[3] |
| Distance | 26.733 ± 0.007 ly (8.196 ± 0.002 pc) |
| Absolute magnitude (MV) | 6.27[5] |
| Orbit[6] | |
| Period (P) | 475.2 yr |
| Semi-major axis (a) | 7.826″ |
| Eccentricity (e) | 0.5344 |
| Inclination (i) | 140.5° |
| Longitude of the node (Ω) | 13.7° |
| Periastron epoch (T) | 1811.90 |
| Argument of periastron (ω) (secondary) | 18.6° |
| Details | |
| p Eri A | |
| Mass | 0.78[7] M☉ |
| Radius | 0.75[1] R☉ |
| Luminosity | 0.339[8] L☉ |
| Surface gravity (log g) | 4.63[7] cgs |
| Temperature | 5,077[7] K |
| Metallicity [Fe/H] | –0.24[7] dex |
| Rotation | 30[9] days |
| Age | 4.94[7] Gyr |
| p Eri B | |
| Mass | 0.77[7] M☉ |
| Radius | 0.77[3] R☉ |
| Luminosity | 0.311[3] L☉ |
| Surface gravity (log g) | 4.65[7] cgs |
| Temperature | 5,117[7] K |
| Metallicity [Fe/H] | –0.19[7] dex |
| Rotation | 39[9] days |
| Age | 1.96[7] Gyr |
| Other designations | |
| p Eri A: HD 10360, HR 486, LTT 903 | |
| p Eri B: HD 10361, HR 487, LTT 902 | |
| Database references | |
| SIMBAD | data |
| p Eri A | |
| p Eri B | |
This system consists of a pair of near identical K-type main-sequence stars with stellar classifications of K2V.[4] Component A has visual magnitude 5.87, while component B is magnitude 5.76.[2] They orbit each other with a period of 475.2 years, an eccentricity of 0.53, and a semimajor axis of 7.8″.[6]
Naming edit
The name "p Eridani", according to Nature, p. 589 (19 April 1883)[10] has been "occasionally miscalled 6 Eridani, which would imply that it was one of Flamsteed's stars. Flamsteed, it is true has a star which he calls 6 Eridani. The designated letter 'p' was attached to a star by Lacaille in the catalogue at the end of his Coelum Australe Stelliferum. The number '6' is merely borrowed from Bode."
The use of Bode numbers was commonly used in the early 19th century, but this antiquated system has now fallen into disuse for more than a century.
See also edit
References edit
- ^ a b c d e f g Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e Hoffleit, D.; Jaschek, C. (1991), The Bright star catalogue, New Haven: Yale University Observatory, Bibcode:1991bsc..book.....H.
- ^ a b c d e f g h Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b Gray, R. O.; et al. (2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
- ^ a b Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
- ^ a b Hartkopf, W. I.; et al. (June 30, 2006), Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory, archived from the original on 2017-08-01, retrieved 2017-06-02.
- ^ a b c d e f g h i j Aguilera-Gómez, Claudia; Ramírez, Iván; Chanamé, Julio (2018), "Lithium abundance patterns of late-F stars: An in-depth analysis of the lithium desert", Astronomy and Astrophysics, 614: A55, arXiv:1803.05922, Bibcode:2018A&A...614A..55A, doi:10.1051/0004-6361/201732209, S2CID 62799777.
- ^ Hinkel, Natalie R.; et al. (October 2017), "A Catalog of Stellar Unified Properties (CATSUP) for 951 FGK-Stars within 30 pc", The Astrophysical Journal, 848 (1): 19, arXiv:1709.04465, Bibcode:2017ApJ...848...34H, doi:10.3847/1538-4357/aa8b0f, S2CID 118941011, 34.
- ^ a b Saar, S. H.; et al. (February 1997), "Rotation, turbulence and evidence for magnetic fields in southern dwarfs", Monthly Notices of the Royal Astronomical Society, 284 (4): 803–810, Bibcode:1997MNRAS.284..803S, doi:10.1093/mnras/284.4.803
- ^ "Our Astronomical Column: The Binary Star p Eridani" (PDF), Nature: 589, 19 April 1883, retrieved 2019-05-27.
Further reading edit
External links edit
- "p Eridani 3?". SolStation. Retrieved 2008-06-21.