Iota Mensae

ι Mensae
Location of ι Mensae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Mensa
Right ascension 05h 35m 36.1787s[1]
Declination −78° 49′ 15.129″[1]
Apparent magnitude (V) 6.00 - 6.05[2]
Characteristics
Spectral type B8 III[3]
B−V color index −0.022[4]
Variable type Ellipsoidal?[2]
Astrometry
Radial velocity (Rv)12.6±4.3[5] km/s
Proper motion (μ) RA: +5.547[1] mas/yr[1]
Dec.: +25.710[1] mas/yr[1]
Parallax (π)3.7076 ± 0.1819 mas[1]
Distance880 ± 40 ly
(270 ± 10 pc)
Absolute magnitude (MV)−1.03[6]
Details
Mass3.6[1] M☉
Radius9.5[1] R☉
Luminosity301[1] L☉
Surface gravity (log g)3.4[7] cgs
Temperature11,272±264[8] K
Metallicity [Fe/H]+0.13[9] dex
Age203[1] Myr
Other designations
ι Men, CD−78°216, HD 38602, HIP 26264, HR 1991, SAO 256214[10]
Database references
SIMBADdata

Iota Mensae is a single star about 880 light years away in the faint constellation Mensa. It has a very slightly variable apparent magnitude of 6.0, making it visible with the naked eye under good skies.

A light curve for Iota Mensae plotted from TESS data[11]

Iota Mensae has a spectral type of B8III, indicating that it has exhausted hydrogen at its core and expanded away from the main sequence. It is about 3.6 times the mass (M☉), 301 times as luminous, and has swollen to 9.5 times the radius of the Sun (R☉). It is calculated to be 314 million years old.

It has been catalogued as a chemically peculiar star with abnormally strong lines of silicon in its spectrum but this classification is now considered doubtful.[12] Its brightness varies by a few hundredths of a magnitude. Its period was initially measured at 2.6 days,[13] but this is now considered to be a period of 5.3 days with primary and secondary minima of a similar depth. The variability is thought to be due to the rotation of the star.[2]

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  2. ^ a b c Cite error: The named reference gcvs was invoked but never defined (see the help page).
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  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
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  12. ^ Cite error: The named reference renson2009 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference gronbech1976 was invoked but never defined (see the help page).