HD 100307 is a suspected variable star in the constellation of Hydra. Its apparent magnitude is 6.16,[2] but interstellar dust makes it appear 0.346 magnitudes dimmer than it should be.[6] It is located some 340 light-years (104 parsecs) away, based on parallax.[1]

HD 100307
Observation data
Epoch J2000      Equinox J2000
Constellation Hydra
Right ascension 11h 32m 23.28291s[1]
Declination −26° 44′ 48.4974″[1]
Apparent magnitude (V) 6.16[2]
Spectral type M2 III[3]
U−B color index +1.99[4]
B−V color index +1.67[4]
Variable type Suspected
Radial velocity (Rv)34.50 ± 0.6[5] km/s
Proper motion (μ) RA: −83.52[1] mas/yr
Dec.: 19.85[1] mas/yr
Parallax (π)4.54 ± 0.36 mas[1]
Distance720 ± 60 ly
(220 ± 20 pc)
Radius67.564 R
Luminosity687.324 ± 72.169 L
Temperature3598 ± 125 K
Other designations
CD−26° 8620, HD 100307, HIP 56293, HR 4445, SAO 179969
Database references

HD 100307 is a M-type red giant. It has evolved from the main sequence to a radius of 67.6 times that of the Sun. It emits 687 times as much energy as the Sun at a surface temperature of 3,598 K.[6]


  1. ^ a b c d e f van Leeuwen, F. (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. ^ a b 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. ^ Houk, Nancy (1982). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 3. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode:1982mcts.book.....H.
  4. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  5. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  6. ^ a b c McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. S2CID 73594365.