U Lacertae

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

U Lacertae
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]
Characteristics
Spectral type M4epIab + B[3]
U−B color index +1.46[2]
B−V color index +2.34[2]
Variable type SRc[3]
Astrometry
Radial velocity (Rv)−68[4] km/s
Proper motion (μ) RA: −3.207 [5] mas/yr
Dec.: −3.150 [5] mas/yr
Parallax (π)0.3519 ± 0.0708[5] mas
Distance2,750[6] pc
Absolute magnitude (MV)−5.6[7]
Details
Mass22[7] M☉
Radius785[8] R☉
Luminosity87,000 - 93,000[8] L☉
Temperature3,535±170[8] 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
SIMBADdata

Despite being in the constellation of Lacerta, U Lacertae is considered to be a member of the Cepheus OB1 association.[9] It has been listed as a member of the open cluster ASCC 123.[10]

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.[11]

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.[12] A study of Hipparcos satellite photometry found an amplitude of 0.77 magnitudes and found no periodicity.[13] 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.[14]

See also

References
  1. 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. Ducati, J. R. (2002). "VizieR On-line Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  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. 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.
  5. 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.
  6. 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. S2CID 118515353.
  7. Stothers, R.; Leung, K. C. (1971). "Luminosities, masses and periodicities of massive red supergiants". Astronomy and Astrophysics. 10: 290. Bibcode:1971A&A....10..290S.
  8. Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
  9. 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. 94: 211. Bibcode:1992A&AS...94..211G.
  10. 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. S2CID 54789717.
  11. 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.
  12. 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.
  13. Adelman, Saul J. (2001). "Stars with the Largest Hipparcos Photometric Amplitudes". Baltic Astronomy. 10: 589. Bibcode:2001BaltA..10..589A.
  14. 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 (1): 15. Bibcode:2014ApJS..211...15Y. doi:10.1088/0067-0049/211/1/15.
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