66 Eridani

Last updated
66 Eridani
Observation data
Epoch J2000        Equinox J2000
Constellation Eridanus
Right ascension 05h 06m 45.65314s [1]
Declination −04° 39 18.5939 [1]
Apparent magnitude  (V)5.12 [2]
Characteristics
Spectral type B9V [3]
U−B color index -0.16 [4]
B−V color index -0.06 [4]
Variable type α2 CVn
Astrometry
Radial velocity (Rv)32.28 ± 0.10 [5]  km/s
Proper motion (μ)RA: 10.70 [1]   mas/yr
Dec.: -0.78 [1]   mas/yr
Parallax (π)10.56 ± 0.34 [1]   mas
Distance 309 ± 10  ly
(95 ± 3  pc)
Absolute magnitude  (MV)0.37 [6]
Orbit [5]
Period (P)5.5226013 ± 0.0000020 d
Eccentricity (e)0.0844 ± 0.0013
Periastron epoch (T)2441356.499 ± 0.017
Argument of periastron (ω)
(secondary)
160.9 ± 1.1°
Semi-amplitude (K1)
(primary)
102.83 ± 0.20 km/s
Semi-amplitude(K2)
(secondary)
100.35 ± 0.19 km/s
Details [5]
66 Eri A
Mass 2.629 ± 0.032  M
Radius 1.948 ± 0.063  R
Luminosity 51.3 ± 3.3  L
Surface gravity (log g)4.28 ± 0.03  cgs
Temperature 11077  K
Rotational velocity (v sin i)17.1 ± 0.2 km/s
Age 30  Myr
66 Eri B
Mass 2.566 ± 0.032  M
Radius 1.919 ± 0.061  R
Luminosity46.9 ± 3.0  L
Surface gravity (log g)4.28 ± 0.03  cgs
Temperature 10914  K
Rotational velocity (v sin i)16.9 ± 0.2 km/s
Other designations
EN Eri, BD−04° 1044, HD  32964, HIP  23794, HR  1657, SAO  131777 [7]
Database references
SIMBAD data

66 Eridani is a binary star in the constellation of Eridanus. The combined apparent magnitude of the system is 5.12 on average. [2] Parallax measurements by Hipparcos put the system at some 309 light-years (95 parsecs) away. [1]

This is a spectroscopic binary: the two stars cannot be individually resolved, but periodic Doppler shifts in its spectrum mean there must be orbital motion. The two stars orbit each other every 5.5226013 days. [5] Their orbit is fairly eccentric, at 0.0844. [5]

The combined spectrum of 66 Eridani matches that of a B-type main-sequence star, [3] and the two stars have similar masses. [5] The spectrum also shows excess of mercury and manganese, as it is a type of chemically peculiar star called a mercury-manganese star. [5] 66 Eridani is an Alpha2 Canum Venaticorum variable. For this reason, it has been given the designation EN Eridani. [7]

Related Research Articles

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Omega Ursae Majoris Binary system in the constellation Ursa Major

Omega Ursae Majoris is the Bayer designation for a binary star system in the northern circumpolar constellation of Ursa Major. It is visible to the naked eye with an apparent visual magnitude of 4.61. Based upon an annual parallax shift of 13.24 mas, it is roughly 246 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.11 due to interstellar dust.

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Tau Virginis

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Pi Virginis

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40 Aurigae is a binary star in the constellation Auriga. Its apparent magnitude is 5.345, meaning it can just barely be seen with the naked eye. Based on parallax estimates made by the Hipparcos spacecraft, the system is located some 340 light-years away.

Tau<sup>4</sup> Eridani Star in the constellation Eridanus

Tau4 Eridani is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.65. The distance to this star can be estimated using the parallax method, which yields a value of roughly 300 light years.

Theta1 Crucis is a spectroscopic binary star system in the southern constellation of Crux. It is visible to the naked eye with an apparent visual magnitude of 4.30m. The distance to this star, as determined using parallax measurements, is around 235 light years.

HR 9038 is a triple star system located thirty-five light-years away, in the constellation Cepheus. Component A is a spectroscopic binary system with an orbital period of 7.753 days and a combined stellar classification of K3 V. Component B is a red dwarf star that orbits the primary pair every 290 years.

EZ Canis Majoris Binary star system in the constellation Canis Major

EZ Canis Majoris is binary system in the constellation of Canis Major. The primary is a Wolf-Rayet star and it is one of the ten brightest Wolf-Rayet stars, brighter than apparent magnitude 7.

88 Tauri, also known as d Tauri, is a multiple star system in the constellation Taurus. It has an apparent magnitude of about 4.25, meaning that it is visible to the naked eye. Based upon parallax measurements made by the Hipparcos spacecraft, the star system is some 156 light-years from the Sun.

HD 106112, also known as CO Camelopardalis, is a star in the constellation Camelopardalis. It has an apparent magnitude of about 5.1, meaning that it is just barely visible to the naked eye. Based upon parallax measurements made by the Hipparcos spacecraft, this star is around 177 light years away from the Sun.

20 Ceti is a single star located around 590 light years away in the equatorial constellation of Cetus. It is faintly visible to the naked eye with apparent magnitude is 4.76. The Bright Star Catalogue has this star classified as M0III, matching an aging red giant star that has consumed the hydrogen at its core and expanded. Houk and Swift (1999) listed an earlier class of K5 III. It has around 56 times the Sun's radius and is radiating 1,044 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,920 K.

Upsilon4 Eridani is a close binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.56. Based upon parallax measurements, the pair are located around 54.6 parsecs (178 ly) from the Sun.

Omega Eridani is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude is 4.37. The distance to this star, as determined by the parallax method, is around 235 light years.

15 Lyncis is a binary star system in the northern constellation of Lynx. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.35. Based on the system's parallax, it is located 178 light-years away. The pair are moving away from the Earth with a heliocentric radial velocity of +2 km/s.

90 Tauri is a star in the zodiac constellation of Taurus, located 144 light years away from the Sun. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.27. 90 Tauri is a member of the Hyades cluster and is listed as a double star.

66 Tauri, also known as r Tauri, is a binary star in the constellation of Taurus. The combined apparent magnitude of the system is 5.098, with the magnitudes of the two components being 5.8 and 5.9, respectively. Parallax measurements by Hipparcos put 66 Tauri at some 400 light-years away.

Rho3 Eridani, Latinized from ρ3 Eridani, is a star located in the constellation Eridanus. It forms an asterism with Rho1 and Rho2 Eridani, south of Cetus, in the upper north east portion of Eridanus. The star has an apparent visual magnitude of 5.26, which is bright enough to be seen with the naked eye on a dark, clear night. The distance to this star, as determined via the parallax method, is about 136 light years.

References

  1. 1 2 3 4 5 6 van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. 1 2 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. 1 2 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 5: 0. Bibcode:1999MSS...C05....0H.
  4. 1 2 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  5. 1 2 3 4 5 6 7 Makaganiuk, V.; Kochukhov, O.; Piskunov, N.; Jeffers, S. V.; Johns-Krull, C. M.; Keller, C. U.; Rodenhuis, M.; Snik, F.; Stempels, H. C.; Valenti, J. A. (2011). "Chemical spots in the absence of magnetic field in the binary Hg Mn star 66 Eridani". Astronomy & Astrophysics. 529: A160. arXiv: 1102.4661 . Bibcode:2011A&A...529A.160M. doi:10.1051/0004-6361/201016302. S2CID   118419097.
  6. Hubrig, S.; et al. (June 2001), "Search for low-mass PMS companions around X-ray selected late B stars", Astronomy and Astrophysics, 372: 152–164, arXiv: astro-ph/0103201 , Bibcode:2001A&A...372..152H, doi:10.1051/0004-6361:20010452, S2CID   17507782.
  7. 1 2 "* 66 Eri". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 13 August 2017.