HD 83953

This article is about I (upper case "i") Hydrae. Not to be confused with l (lower case "L") Hydrae or ι (iota) Hydrae.
HD 83953
Observation data
Epoch J2000      Equinox J2000
Constellation Hydra
Right ascension 09h 41m 17.00785s[1]
Declination −23° 35′ 29.4325″[1]
Apparent magnitude (V) 4.76[2]
Characteristics
Spectral type B5 V[3]
B−V color index −0.117±0.015[2]
Astrometry
Radial velocity (Rv)+16.05±1.5[4] km/s
Proper motion (μ) RA: −29.969[1] mas/yr
Dec.: +1.914[1] mas/yr
Parallax (π)6.5733 ± 0.2851 mas[1]
Distance500 ± 20 ly
(152 ± 7 pc)
Absolute magnitude (MV)−1.19[2]
Details
Mass4.57±0.08[5] M☉
Radius4.00±0.08[6] R☉
Luminosity708+60
−55[5] L☉
Surface gravity (log g)2.54±0.03[6] cgs
Temperature15,000±150[6] K
Rotational velocity (v sin i)315[5][7] km/s
Other designations
I Hya, BD−22° 2684, HD 83953, HIP 47522, HR 3858, SAO 177840[8]
Database references
SIMBADdata

HD 83953 (I Hydrae) is a single,[9] blue-white hued star in the equatorial constellation of Hydra. It is visible to the naked eye, having an apparent visual magnitude of 4.76.[2] Based upon an annual parallax shift of 6.6 mas,[1] the distance to this star is estimated as 500 light years. It is moving further from Earth with a heliocentric radial velocity of +16 km/s.[4]

This is a B-type main-sequence star with a stellar classification of B5 V.[3] It has been known to be a Be star since 1926, when an Hβ emission line was discovered in the stellar spectrum by Mount Wilson Observatory.[10] This energy is coming from a circumstellar envelope of heated gas that has been expelled from the central star and formed a thin orbiting disk.[11] HD 83953 is spinning rapidly with a projected rotational velocity of 315 km/s, giving the star an oblate shape with an equatorial bulge that is 18% larger than the polar radius.[7]

HD 83953 has 4.6[5] times the mass of the Sun and 4.0[6] times the Sun's radius. It is radiating 708[5] times the Sun's luminosity from its photosphere at an effective temperature of 15,000 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 Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Becker2015 was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference zorec2012 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference Arcos2018 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference belle2012 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Merrill1933 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Arcos2017 was invoked but never defined (see the help page).