U Lacertae

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U Lacertae
Lacerta constellation map.svg
Red circle.svg
Location of U Lacertae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Lacerta
Right ascension 22h 47m 43.42677s[1]
Declination 55° 09′ 30.3036″[1]
Apparent magnitude (V) 9.40[2]
Spectral type M4epIab + B[3]
U−B color index +1.46[2]
B−V color index +2.34[2]
Variable type SRc[3]
Proper motion (μ) RA: -3.333 ± 0.054 [4] mas/yr
Dec.: -3.039 ± 0.052 [4] mas/yr
Parallax (π)2.03 ± 0.91[4] mas
Distance2,750[5] pc
Absolute magnitude (MV)−5.6[6]
Mass22[6] M
Radius1,022[7] R
Diameter1,022[7] D
Luminosity147,000[8] L
Temperature3,535[9] K
Other designations
U Lac, HIP 112545, PPM 411, GSC 03988-01641, IRC+50446, TYC 3988-1641-1, BD+54 2863, HD 215924, 2MASS J22474341+5509303, AAVSO 2243+54
Database references

U Lacertae is a spectroscopic binary star in the constellation Lacerta.

Despite being in the constellation of Lacerta, U Lacertae is considered to be a member of the Cepheus OB1 association.[10] It has been listed as a member of the open cluster ASCC 123.[11]

U Lacertae is a VV Cephei binary consisting of a red supergiant and a small hot companion. The companion has been identified from a high excitation component in the spectrum and from radial velocity variations, but the orbit is unknown.[12]

U Lacertae is a variable star classified as a semiregular variable.[3] The periodicity is uncertain but a main period of 150 days and a long secondary period of 550 – 690 days have been suggested.[13] A study of Hipparcos satellite photometry found an amplitude of 0.77 magnitudes and found no periodicity.[14] The General Catalogue of Variable Stars lists an amplitude of 2.7 magnitudes.[3]

Water masers have been detected around U Lacertae, common in the extended atmospheres of very luminous cool stars.[15]

See also[edit]


  1. 1.0 1.1 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653. arXiv:0708.1752. Bibcode 2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. 2.0 2.1 2.2 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. 3.0 3.1 3.2 3.3 U Lac, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line November 12, 2010.
  4. 4.0 4.1 4.2 Gaia Collaboration (2016). "VizieR Online Data Catalog: Gaia DR1 (Gaia Collaboration, 2016)". VizieR On-line Data Catalog: I/337. Originally published in: Astron. Astrophys 1337. Bibcode 2016yCat.1337....0G.
  5. Reiter, Megan; Marengo, Massimo; Hora, Joseph L.; Fazio, Giovanni G. (2015). "A Spitzer/IRAC characterization of Galactic AGB and RSG stars". Monthly Notices of the Royal Astronomical Society 447 (4): 3909. arXiv:1501.02749. Bibcode 2015MNRAS.447.3909R. doi:10.1093/mnras/stu2725.
  6. 6.0 6.1 Stothers, R.; Leung, K. C. (1971). "Luminosities, masses and periodicities of massive red supergiants". Astronomy and Astrophysics 10: 290. Bibcode 1971A&A....10..290S.
  7. {{{1}}}
  8. Mauron, N.; Josselin, E. (2011). "The mass-loss rates of red supergiants and the de Jager prescription". Astronomy and Astrophysics 526: A156. arXiv:1010.5369. Bibcode 2011A&A...526A.156M. doi:10.1051/0004-6361/201013993.
  9. Verhoelst, T.; Van Der Zypen, N.; Hony, S.; Decin, L.; Cami, J.; Eriksson, K. (2009). "The dust condensation sequence in red supergiant stars". Astronomy and Astrophysics 498: 127. arXiv:0901.1262. Bibcode 2009A&A...498..127V. doi:10.1051/0004-6361/20079063.
  10. Garmany, C. D.; Stencel, R. E. (1992). "Galactic OB associations in the northern Milky Way Galaxy. I - Longitudes 55 deg to 150 deg". Astronomy and Astrophysics Supplement Series (ISSN 0365-0138) 94: 211. Bibcode 1992A&AS...94..211G.
  11. Zejda, M.; Paunzen, E.; Baumann, B.; Mikulášek, Z.; Liška, J. (2012). "Catalogue of variable stars in open cluster fields". Astronomy & Astrophysics 548: A97. arXiv:1211.1153. Bibcode 2012A&A...548A..97Z. doi:10.1051/0004-6361/201219186.
  12. Burki, G.; Mayor, M. (1983). "Nineteen new spectroscopic binaries and the rate of binary stars among F-M supergiants". Astronomy and Astrophysics 124: 256. Bibcode 1983A&A...124..256B.
  13. Houk, N. (1963). "V1280 Sagttarii and the other long-period variables with secondary period". Astronomical Journal 68: 253. Bibcode 1963AJ.....68..253H. doi:10.1086/108948.
  14. Adelman, Saul J. (2001). "Stars with the Largest Hipparcos Photometric Amplitudes". Baltic Astronomy 10: 589. Bibcode 2001BaltA..10..589A.
  15. Yoon, Dong-Hwan; Cho, Se-Hyung; Kim, Jaeheon; Yun, Young joo; Park, Yong-Sun (2014). "SiO and H2O Maser Survey toward Post-asymptotic Giant Branch and Asymptotic Giant Branch Stars". The Astrophysical Journal Supplement 211: 15. Bibcode 2014ApJS..211...15Y. doi:10.1088/0067-0049/211/1/15.

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