LY Aurigae

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Binary star in the constellation Auriga

title: "LY Aurigae" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["auriga", "beta-lyrae-variables", "henry-draper-catalogue-objects", "hipparcos-objects", "o-type-giants", "eclipsing-binaries", "objects-with-variable-star-designations", "b-type-giants", "durchmusterung-objects", "o-type-bright-giants", "multiple-star-systems"] description: "Binary star in the constellation Auriga" topic_path: "general/auriga" source: "https://en.wikipedia.org/wiki/LY_Aurigae" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Binary star in the constellation Auriga ::

| name=LY Aurigae | image = [[File:LYAurigaeLocation.png|240px]] | caption = LY Aurigae is the bright star, with the red arrow pointing at it, in the southeast corner of this picture of Messier 38 | credit = | epoch = J2000 | ra = | dec = | appmag_v = 6.85)}} | constell = Auriga | class = O9II + O9III + B0.5III | r-i = | v-r = | b-v = +0.20 | u-b = −0.78 | variable = β Lyr | radial_v = 5.40 | prop_mo_ra = | prop_mo_dec = | parallax = 3.28 | p_error = 2.40 | parallax_footnote = | dist_pc = 2,090 | dist_ly = 6,800 | dist_footnote = | absmag_v = −5.62 + −5.11 + −4.43 | reference = | primary = Aa | name = Ab | period = | period_unitless = 4.0025 days | axis = | axis_unitless = | eccentricity = 0.0 | inclination = 87.7 | node = | periastron = | periarg = | periarg_primary = | k1 = 161.9 | k2 = 294.3 | reference = | primary = Ba | name = Bb | period = | period_unitless = 20.4642 days | axis = | axis_unitless = | eccentricity = 0.246 | inclination = | node = | periastron = | periarg = | periarg_primary = | k1 = 33.0 | k2 = | source = | component1 = Aa | mass = 25.5 | radius = 16.1 | luminosity = 214,000 | temperature = 31,000 | metal = | gravity = 3.425 | rotational_velocity = 194 | age = | source = | component1 = Ab | mass = 14.0 | radius = 12.6 | luminosity = 135,000 | temperature = 31,150 | metal = | gravity = 3.378 | rotational_velocity = 152 | age = | source = | component1 = B | mass = | radius = | luminosity = 47,000 | temperature = 26,000 | metal = | gravity = 4.00 | rotational_velocity = 30 | age_myr = 5 | names = LY Aurigae, BD+35°1137, HD 35921, SAO 58105, HIP 25733, WDS J05297+3523, AAVSO 0523+35 | Simbad = HD+35921 | ARICNS =

LY Aurigae is a multiple star system in the constellation Auriga. It is an eclipsing binary variable star, dropping in brightness by 0.7 magnitudes every 4 days. The system is around 6,800 light years away in the Auriga OB1 stellar association.

System

LY Aurigae is a close visual binary. The two stars are magnitude 6.85 and magnitude 8.35 0.6 arc-seconds apart. Each star is also a spectroscopic binary.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/7/79/LYAurLightCurve.png" caption="visual band]] [[light curve]] for LY Aurigae, adapted from Mayer ''et al.'' (2013)"] ::

In 1965, Pavel Mayer reported that the star, then called HD 35921, is a variable star. By 1968, he had determined that it is an eclipsing binary. It was given its variable star designation, LY Aurigae, in 1970. LY Aur A is a double-lined spectroscopic binary with an O9 bright giant and an O9 giant star in contact and eclipsing each other as they orbit every 4 days. It is classified as a Beta Lyr eclipsing variable system. The primary eclipse is 0.69 magnitudes deep and the secondary eclipse is 0.60 magnitudes. Because of the contact nature of the system and the deformed shapes of the stars, the magnitude varies constantly throughout the orbital cycle. The orbital period is slowly changing due to mass exchange between the stars. Each star is over a hundred thousand times the luminosity of the sun.

LY Aur B is a single-lined spectroscopic binary with an orbital period of 20.5 days. It is probably an early B main sequence star and the companion is undetectable. The two stars combined are 47,000 times the luminosity of the sun.

Notes

References

References

  1. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S.
  2. (1988). "New photometric data on LY Aurigae". Contributions of the Astronomical Institute of Brno.
  3. Stickland, D. J.. (1994). "Spectroscopic binary orbits from ultraviolet radial velocities. Paper 15: LY Aurigae (HD 35921)". The Observatory.
  4. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics.
  5. (2013). "The O-type eclipsing contact binary LY Aurigae - member of a quadruple system". Astronomy & Astrophysics.
  6. (2015). "A new catalogue of Strömgren-Crawford uvbyβ photometry". Astronomy & Astrophysics.
  7. (2002). "The Tycho double star catalogue". Astronomy and Astrophysics.
  8. (2006). "A catalogue of eclipsing variables". Astronomy and Astrophysics.
  9. (February 1968). "The Eclipsing Variable HD 35921". Publications of the Astronomical Society of the Pacific.
  10. (November 2013). "The O-type eclipsing contact binary LY Aurigae – member of a quadruple system". Astronomy & Astrophysics.
  11. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics.
  12. (October 1970). "57th Name-List of Variable Stars". Information Bulletin on Variable Stars.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

aurigabeta-lyrae-variableshenry-draper-catalogue-objectshipparcos-objectso-type-giantseclipsing-binariesobjects-with-variable-star-designationsb-type-giantsdurchmusterung-objectso-type-bright-giantsmultiple-star-systems