Binary star system in the constellation Eridanus
p Eridani Location of p Eridani (circled in red)
Observation dataEpoch 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−Bcolor index +0.59 / +0.53[ 2] B−Vcolor index +0.90 / +0.87[ 2] Astrometry A Radial velocity (Rv )± 0.12[ 1] km/s Proper motion (μ)RA: +262.615mas /yr [ 1] Dec.: +14.961mas /yr [ 1] Parallax (π)122.1088± 0.0365 mas [ 1] Distance 26.710 ± 0.008 ly pc ) Absolute magnitude (MV )6.25[ 5] B Radial velocity (Rv )± 0.12[ 3] km/s Proper motion (μ)RA: +309.230mas /yr [ 3] Dec.: +10.815mas /yr [ 3] Parallax (π)122.0035± 0.0319 mas [ 3] Distance 26.733 ± 0.007 ly pc ) Absolute magnitude (MV )6.27[ 5] Orbit [ 6] Period (P)± 23yr Semi-major axis (a)± 0.26Eccentricity (e)± 0.063Inclination (i)± 4Longitude of the node (Ω)± 7.9Periastron epoch (T)± 6Argument of periastron (ω)± 10Details p Eri A Mass +0.04 [ 7] M ☉ Radius ± 0.02[ 7] R ☉ Luminosity ± 0.02[ 7] L ☉ Surface gravity (log g )± 0.05[ 7] cgs Temperature +43 [ 7] K Metallicity [Fe/H] –0.24[ 8] dex Rotation 30[ 9] Age 4.94[ 8] Gyr p Eri B Mass +0.04 [ 7] M ☉ Radius +0.01 [ 7] R ☉ Luminosity ± 0.02[ 7] L ☉ Surface gravity (log g )± 0.060[ 7] cgs Temperature ± 43[ 7] K Metallicity [Fe/H] –0.19[ 8] dex Rotation 39[ 9] Age 1.96[ 8] Gyr Other designations DUN 5,p Eri ,CD −56°328GJ 66HIP 7751SAO 232490WDS 01398-5612p Eri A :HD 10360HR 486LTT 903p Eri B :HD 10361HR 487LTT 902Database references SIMBAD data p Eri A p Eri B
p Eridani is abinary star system in theconstellation ofEridanus (theRiver ) whose distance from the Sun is 26.7 light-years based uponparallax . It was found to be adouble star in December 1825 byJames Dunlop inAustralia at his home at Paramatta, now speltParramatta . It is visible to the naked eye as a dim, orange-hued star. The system is moving further from the Earth with a heliocentricradial velocity of about
This system consists of a pair of near identicalK-type main-sequence stars withstellar classifications of K2V.[ 4] [ 2] period of 394 years, aneccentricity of 0.576, and asemimajor axis of″ [ 6]
The name "p Eridani", according toNature [ 10] 6 Eridani , which would imply that it was one ofFlamsteed's stars . Flamsteed, it is true has a star which he calls6 Eridani . The designated letter 'p' was attached to a star byLacaille in the catalogue at the end of his Coelum Australe Stelliferum. The number '6' is merely borrowed fromBode ."
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. The Flamsteed designation6 Eridani refers to a different star.[ 11]
^a b c d e 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 atVizieR .^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 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 atVizieR .^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 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 . ^a b c d e f g h i j 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 ^a b c d 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 . ^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, retrieved2019-05-27 .^ "* 6 Eri" .SIMBAD Centre de données astronomiques de Strasbourg .
