Eta1 Hydri

For other stars with this Bayer designation, see η Hydri.
Eta1 Hydri
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydrus
Right ascension 01h 52m 34.78591s[1]
Declination −67° 56′ 40.1823″[1]
Apparent magnitude (V) 6.76[2]
Characteristics
Spectral type B9 V[3]
B−V color index −0.050±0.002[4]
Astrometry
Radial velocity (Rv)+15.0±3.0[2] km/s
Proper motion (μ) RA: +18.270[1] mas/yr
Dec.: −8.948[1] mas/yr
Parallax (π)5.2719 ± 0.0548 mas[1]
Distance619 ± 6 ly
(190 ± 2 pc)
Absolute magnitude (MV)+0.77[5]
Details
Luminosity91[6] L☉
Temperature9,816[6] K
Age311[5] Myr
Other designations
η1 Hyi, CD−68°87, HD 11733, HIP 8751, SAO 248455[7]
Database references
SIMBADdata

Eta1 Hydri, Latinized from η1 Hydri, is a blue-white hued star in the southern constellation of Hydrus. It has an apparent visual magnitude of 6.76,[2] which may be too faint to be visible to the naked eye. Based upon an annual parallax shift of 5.27 mas as measured from Earth,[1] the system is located about 619 light years distant from the Sun. At that distance, the visual magnitude of the star is diminished by 0.10 magnitudes of extinction due to interstellar dust.[5] The star is drifting further away with a heliocentric radial velocity of +15 km/s.[2]

This is a B-type main-sequence star with a stellar classification of B9 V[3] that was suspected in 1939 by Herbert Schneller of being variable.[8] However, this may have been based on a photographic plate that was later rejected.[9] It is listed in the General Catalogue of Variable Stars, but marked as probably constant.[10]

The star is about 311[5] million years old and is radiating 91 times the luminosity of the Sun from its photosphere at an effective temperature of 9,816 K.[6]

  1. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1979 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference AAVSO was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Sahade1950 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).