P Eridani

p Eridani
Location of p Eridani (circled in red)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Eridanus
A
Right ascension 01h 39m 47.813s
Declination −56° 11′ 35.94″
Apparent magnitude (V) 5.76
B
Right ascension 01h 39m 47.565s
Declination −56° 11′ 47.21″
Apparent magnitude (V) 5.87
Characteristics
Spectral type K2V + K2V
U−B color index +0.59 / +0.53
B−V color index +0.90 / +0.87
Astrometry
A
Radial velocity (Rv)+21.74±0.12 km/s
Proper motion (μ) RA: +262.615 mas/yr
Dec.: +14.961 mas/yr
Parallax (π)122.1088±0.0365 mas
Distance26.710 ± 0.008 ly
(8.189 ± 0.002 pc)
Absolute magnitude (MV)6.25
B
Radial velocity (Rv)+20.15±0.12 km/s
Proper motion (μ) RA: +309.230 mas/yr
Dec.: +10.815 mas/yr
Parallax (π)122.0035±0.0319 mas
Distance26.733 ± 0.007 ly
(8.196 ± 0.002 pc)
Absolute magnitude (MV)6.27
Orbit
Period (P)394±23 yr
Semi-major axis (a)7.24±0.26"
(59.3 AU)
Eccentricity (e)0.576±0.063
Inclination (i)141±4°
Longitude of the node (Ω)6.8±7.9°
Periastron epoch (T)1817±6
Argument of periastron (ω)
(secondary)		360±10°
Details
p Eri A
Mass0.77+0.04
−0.03 M☉
Radius0.76±0.02 R☉
Luminosity0.34±0.02 L☉
Surface gravity (log g)4.60±0.05 cgs
Temperature5,046+43
−40 K
Metallicity [Fe/H]–0.24 dex
Rotation30 days
Age4.94 Gyr
p Eri B
Mass0.76+0.04
−0.02 M☉
Radius0.72+0.01
−0.02 R☉
Luminosity0.31±0.02 L☉
Surface gravity (log g)4.630±0.060 cgs
Temperature5,076±43 K
Metallicity [Fe/H]–0.19 dex
Rotation39 days
Age1.96 Gyr
Other designations
DUN 5, p Eri, CD−56°328, GJ 66, HIP 7751, SAO 232490, WDS 01398-5612
p Eri A: HD 10360, HR 486, LTT 903
p Eri B: HD 10361, HR 487, LTT 902
Database references
SIMBADdata
p Eri A
p Eri B

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 is visible to the naked eye as a dim, orange-hued star, about 1° 5′ from the bright star Achernar. The system is moving further from the Earth with a heliocentric radial velocity of about +20 km/s.

This system was found to be a double star in December 1825 by James Dunlop in Australia at his home at Paramatta, now spelt Parramatta. It consists of a pair of near identical K-type main-sequence stars with stellar classifications of K2V. Component A has visual magnitude 5.87, while component B is magnitude 5.76. They orbit each other with a period of 394 years, an eccentricity of 0.576, and a semimajor axis of 7.24″.

Naming

The designation p Eridani was given to this star by Lacaille in his star catalogue Coelum Australe Stelliferum. Historically, it was sometimes also called 6 Eridani, which resembles a Flamsteed designation but actually comes from Bode. Bode numbers were commonly used in the early 19th century, but this antiquated system has now fallen into disuse for more than a century. The Flamsteed designation 6 Eridani refers to a different star.

See also

Notes

  1. ↑ Semi-major axis in AU = = 59.3 AU; as the eccentricity is 0.576, the distance fluctuates between 42.4% and 157.6% of that, roughly from 25.1 AU to 93.4 AU.

References

  1. 1 2 3 4 5 6 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.
  2. 1 2 3 4 5 Hoffleit, D.; Jaschek, C. (1991), The Bright star catalogue, New Haven: Yale University Observatory, Bibcode:1991bsc..book.....H.
  3. 1 2 3 4 5 6 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.
  4. 1 2 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.
  5. 1 2 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.
  6. 1 2 Izmailov, Igor; Khovritchev, Maxim (January 2025), "New Orbital Parameters of 850 Wide Visual Binary Stars and Their Statistical Properties", Research in Astronomy and Astrophysics, 25 (1): 015016, Bibcode:2025RAA....25a5016I, doi:10.1088/1674-4527/ad9da3, ISSN 1674-4527.
  7. 1 2 3 4 5 6 7 8 9 10 Harada, Caleb K.; et al. (June 2024), "Setting the Stage for the Search for Life with the Habitable Worlds Observatory: Properties of 164 Promising Planet-survey Targets", The Astrophysical Journal Supplement Series, 272 (2), id. 30, arXiv:2401.03047, Bibcode:2024ApJS..272...30H, doi:10.3847/1538-4365/ad3e81.
  8. 1 2 3 4 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.
  9. 1 2 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
  10. 1 2 "* p Eri". SIMBAD. Centre de données astronomiques de Strasbourg.
  11. ↑ Dunlop, James (1828), "Approximate Places of Double Stars in the Southern Hemisphere, observed at Paramatta in New South Wales", Memoirs of the Astronomical Society of London, 3: 257
  12. ↑ "Our Astronomical Column: The Binary Star p Eridani", Nature, 27: 589, 19 April 1883, doi:10.1038/027589a0.
  13. ↑ "* 6 Eri". SIMBAD. Centre de données astronomiques de Strasbourg.

Further reading