Eta Tucanae

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Template:Short description

Eta Tucanae
Template:Location mark
Location of η Tucanae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Tucana
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) +5.00[2]
Characteristics
Spectral type A1V[2]
U−B Template:Engvar +0.08[3]
B−V Template:Engvar +0.06[3]
Astrometry
Radial velocity (Rv)+32.50[4] km/s
Proper motion (μ) RA: +78.850[1] mas/yr
Dec.: −62.049[1] mas/yr
Parallax (π)21.2425±0.3639 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)1.62[5]
Details
Mass1.94[6] Template:Solar mass
Radius1.8[7] Template:Solar radius
Luminosity23[8] Template:Solar luminosity
Surface gravity (log g)4.31[9] cgs
Temperature9,057[8] K
Rotational velocity (v sin i)190[6] km/s
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[10]
Database references
SIMBADdata

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Eta Tucanae, Latinized from η Tucanae, is a probable binary star[6] system in the southern constellation of Tucana, a few degrees to the north of Epsilon Tucanae. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of +5.00.[2] parallax measurements provide a distance estimate of about 154 light years from the Sun, and it is drifting further away with a mean radial velocity of +32.5 km/s.[4] It is a member of the 30 million year old Tucana-Horologium association of co-moving stars.[6][2]

The radial velocity for Eta Tucanae displays strong oscillations, suggesting this is a spectroscopic binary system. A companion was directly detected in 2014, but this result has some unexplained anomalies.[6] The primary component is an A-type main-sequence star with a stellar classification of A1V.[2] It is spinning rapidly with a projected rotational velocity of 190 km/s,[6] giving it an equatorial bulge that is 15% larger than the polar radius.[11] The star has 1.9[6] times the mass of the Sun and 1.8[7] times the Sun's radius. It is radiating 23[8] times the luminosity of the Sun from its photosphere at an effective temperature of 9,057 K.[8]

References

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  3. a b Script error: No such module "Citation/CS1".Vizier catalog entry
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  5. Script error: No such module "Citation/CS1". Vizier catalog entry
  6. a b c d e f g Script error: No such module "Citation/CS1".
  7. a b Script error: No such module "Citation/CS1". Vizier catalog entry
  8. a b c d Script error: No such module "Citation/CS1". Vizier catalog entry
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  10. Template:Cite simbad
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Template:Stars of Tucana