p Eridani

p Eridani
Observation data; Epoch J2000.0 Equinox J2000.0
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
Distance	26.710 ± 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
Distance	26.733 ± 0.007 ly ; (8.196 ± 0.002 pc)
Absolute magnitude (MV)	6.27
Orbit
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 M☉
Radius	0.75 R☉
Luminosity	0.339 L☉
Surface gravity (log g)	4.63 cgs
Temperature	5,077 K
Metallicity [Fe/H]	–0.24 dex
Rotation	30 days
Age	4.94 Gyr
p Eri B
Mass	0.77 M☉
Radius	0.77 R☉
Luminosity	0.311 L☉
Surface gravity (log g)	4.65 cgs
Temperature	5,117 K
Metallicity [Fe/H]	–0.19 dex
Rotation	39 days
Age	1.96 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
SIMBAD	data
	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 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.

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

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.

References

^ ^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.

External links

"p Eridani 3?". SolStation. Retrieved 2008-06-21.

[dr3a-1] ^ ^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.

[hr-2] Hoffleit, D.; Jaschek, C. (1991), The Bright star catalogue, New Haven: Yale University Observatory, Bibcode:1991bsc..book.....H.

[dr3b-3] ^ ^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.

[gray-4] 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.

[Holmberg2009-5] 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.

[Hartkopf2006-6] 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.

[ag2018-7] ^ ^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.

[Hinkel2017-8] 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.

[mnras284_803-9] 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

[Nature1883-10] "Our Astronomical Column: The Binary Star p Eridani" (PDF), Nature: 589, 19 April 1883, retrieved 2019-05-27.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

Observation data Epoch J2000.0 Equinox J2000.0
Constellation	Eridanus
A
Right ascension	01^h 39^m 47.813^s^[1]
Declination	−56° 11′ 35.94″^[1]
Apparent magnitude (V)	5.76^[2]
B
Right ascension	01^h 39^m 47.565^s^[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 (R_v)	+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 (M_V)	6.25^[5]
B
Radial velocity (R_v)	+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 (M_V)	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
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
SIMBAD	data
	p Eri A
	p Eri B

p Eridani

Naming

See also

References

Further reading

External links