HD_44780

HD 44780

HD 44780

Binary star system in the constellation Gemini

For the Hitachi product, see Hitachi HD44780 LCD controller.

HD 44780 is a binary star system in the northern constellation of Gemini, located about 3° north of Mu Geminorum.[1][7] The pair have a combined apparent visual magnitude of 6.35,[3] which is near the lower limit of visibility to the naked eye. Although it is above magnitude 6.5, it was not included in the Bright Star Catalogue;[1] the designation HD 44780 comes from the Henry Draper catalogue. Based upon parallax measurements, the system is located at a distance of approximately 960 light years from the Sun. It is drifting further away with a radial velocity of +17 km/s.[3]

Quick Facts Constellation, Right ascension ...

The variable velocity of this system was first noted during a study at Mount Wilson observatory in 1952.[1] It is a double-lined spectroscopic binary[5] system with an orbital period of 1.581 years and an eccentricity of 0.24. Both components are similar, aging giant stars, a relatively rare combination.[1] Their combined spectrum matches a stellar classification of K2 III;[4] with the secondary being a slightly earlier type than the primary. They have an age of about 400 million years, with masses 3.10 and 3.02 times that of the Sun.[5]

References

  1. [1]
    Griffin, R. F. (April 1986), "The spectroscopic orbits of HD 44780 and 65 Geminorum", Journal of the Royal Astronomical Society of Canada, 80: 91–108, Bibcode:1986JRASC..80...91G.
  2. [2]
    Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  3. [3]
    Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  4. [4]
    Heard, John Frederick (1956), "The radial velocities, spectral classes and photographic magnitudes of 1041 late-type stars", Publications of the David Dunlap Observatory, 2 (4), University of Toronto, Toronto, Canada: University of Toronto Press: 107–143, Bibcode:1956PDDO....2..107H.
  5. [5]
    Pourbaix, D.; Boffin, H. M. J. (February 2003), "Reprocessing the Hipparcos Intermediate Astrometric Data of spectroscopic binaries. II. Systems with a giant component", Astronomy and Astrophysics, 398 (3): 1163–1177, arXiv:astro-ph/0211483, Bibcode:2003A&A...398.1163P, doi:10.1051/0004-6361:20021736, S2CID 12361870.
  6. [6]
    "HD 44780". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2011-11-30.
  7. [7]
    HD 044780, VizieR, retrieved 2011-11-30.
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