Binary star system in the constellation Eridanus
p Eridani 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: 262.615[ 1] mas /yr Dec.: 14.961[ 1] mas /yr 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: 309.230[ 3] mas /yr Dec.: 10.815[ 3] mas /yr 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)475.2yr 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)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 –0.24[ 7] dex Rotation 30[ 9] 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 –0.19[ 7] dex Rotation 39[ 9] Age 1.96[ 7] 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 475.2 years, aneccentricity of 0.53, 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.
^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 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 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 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 Hartkopf, W. I.; et al. (June 30, 2006),Sixth Catalog of Orbits of Visual Binary Stars the original on 2017-08-01, retrieved2017-06-02 . ^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, retrieved2019-05-27 .
