4 Lacertae

4 Lacertae
	Location of 4 Lacertae (circled in red)
Observation data; Epoch J2000 Equinox ICRS
Constellation	Lacerta
Right ascension	22h 24m 30.99149s
Declination	+49° 28′ 35.0106″
Apparent magnitude (V)	4.55
Characteristics
Evolutionary stage	Blue supergiant (blue loop)
Spectral type	A0 Ib
B−V color index	0.092±0.034
Astrometry
Radial velocity (Rv)	−26.0±1.7 km/s
Proper motion (μ)	RA: −5.274(82)‍ mas/yr ; Dec.: −3.303(96)‍ mas/yr
Parallax (π)	1.2656±0.0891 mas
Distance	2,600 ± 200 ly ; (790 ± 60 pc)
Absolute magnitude (MV)	−4.42
Details
Mass	19+13; −8 M☉
Radius	36 ± 5 R☉
Luminosity	17,000+3,000; −2,500 L☉
Surface gravity (log g)	2.18 cgs
Temperature	11,000±600 K
Metallicity [Fe/H]	0.28±0.04 dex
Rotational velocity (v sin i)	28±3 km/s
Age	25.1±2.5 Myr
Other designations
	4 Lac, BD+48°3715, HD 212593, HIP 110609, HR 8541, SAO 51970, 2MASS J22243097+4928351
Database references
SIMBAD	data

4 Lacertae is a single blue supergiant star in the northern constellation Lacerta, located about 2,600 light years away. This object visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.55. It is moving closer to the Earth with a heliocentric radial velocity of −26 km/s. This star is a suspected member of the Lac OB1 association.

This blue supergiant star has a stellar classification of A0 Ib. The surface abundances show evidence of material that has been processed via the CNO cycle at the core. It has ten times the mass of the Sun and has expanded to about 36 times the Sun's radius. The star is around 25 million years old and is spinning with a projected rotational velocity of 28 km/s. It is believed to be a blue loop star that has already spent time as a red supergiant after fusing the hydrogen within its core.

Notes

1 2 Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
${\sqrt {{\biggl (}{\frac {5,772}{11,000}}{\biggr )}^{4}\cdot 10^{4.23}}}=36\ R_{\odot }$ .

References

1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
1 2 3 4 5 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.
1 2 3 Yüce, Kutluay (2005), "Spectral Analysis of 4 Lacertae and ν Cephei", Baltic Astronomy, 14: 51–82, Bibcode:2005BaltA..14...51Y.
1 2 Gray, R. O.; Garrison, R. F. (1987), "The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", The Astrophysical Journal Supplement Series, 65: 581, Bibcode:1987ApJS...65..581G, doi:10.1086/191237.
1 2 Kaltcheva, Nadia (October 2009), "Lacerta OB1 Revisited", Publications of the Astronomical Society of the Pacific, 121 (884): 1045–1053, Bibcode:2009PASP..121.1045K, doi:10.1086/606037, S2CID 120329065.
1 2 3 4 Markova, N.; Puls, J. (2008), "Bright OB stars in the Galaxy. IV. Stellar and wind parameters of early to late B supergiants", Astronomy and Astrophysics, 478 (3): 823, arXiv:0711.1110, Bibcode:2008A&A...478..823M, doi:10.1051/0004-6361:20077919, S2CID 14510634
1 2 3 4 Nurmakhametova, Shakhida T.; Umirova, Aziza B.; Vaidman, Nadezhda L.; Miroshnichenko, Anatoly S.; Khokhlov, Serik A.; Khokhlov, Azamat A.; Agishev, Damir T.; Alimbetova, Dina A. (2026-04-09), "Effective Temperatures of BA-Type Supergiants from SED Fitting", Galaxies, 14 (2): 32, doi:10.3390/galaxies14020032, ISSN 2075-4434.
↑ Gáspár, András; et al. (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal, 826 (2): 171, arXiv:1604.07403, Bibcode:2016ApJ...826..171G, doi:10.3847/0004-637x/826/2/171, S2CID 119241004.
1 2 3 Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
↑ "4 Lac". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-28.
↑ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.

[radius-8] 1 2 Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
${\sqrt {{\biggl (}{\frac {5,772}{11,000}}{\biggr )}^{4}\cdot 10^{4.23}}}=36\ R_{\odot }$ .

[Gaia_DR3-1] 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.

[Anderson2012-2] 1 2 3 4 5 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.

[Yüce2005-3] 1 2 3 Yüce, Kutluay (2005), "Spectral Analysis of 4 Lacertae and ν Cephei", Baltic Astronomy, 14: 51–82, Bibcode:2005BaltA..14...51Y.

[Gray1987-4] 1 2 Gray, R. O.; Garrison, R. F. (1987), "The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", The Astrophysical Journal Supplement Series, 65: 581, Bibcode:1987ApJS...65..581G, doi:10.1086/191237.

[Kaltcheva2009-5] 1 2 Kaltcheva, Nadia (October 2009), "Lacerta OB1 Revisited", Publications of the Astronomical Society of the Pacific, 121 (884): 1045–1053, Bibcode:2009PASP..121.1045K, doi:10.1086/606037, S2CID 120329065.

[markova-6] 1 2 3 4 Markova, N.; Puls, J. (2008), "Bright OB stars in the Galaxy. IV. Stellar and wind parameters of early to late B supergiants", Astronomy and Astrophysics, 478 (3): 823, arXiv:0711.1110, Bibcode:2008A&A...478..823M, doi:10.1051/0004-6361:20077919, S2CID 14510634

[Nurmakhametova2026-7] 1 2 3 4 Nurmakhametova, Shakhida T.; Umirova, Aziza B.; Vaidman, Nadezhda L.; Miroshnichenko, Anatoly S.; Khokhlov, Serik A.; Khokhlov, Azamat A.; Agishev, Damir T.; Alimbetova, Dina A. (2026-04-09), "Effective Temperatures of BA-Type Supergiants from SED Fitting", Galaxies, 14 (2): 32, doi:10.3390/galaxies14020032, ISSN 2075-4434.

[Gáspár2016-9] Gáspár, András; et al. (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal, 826 (2): 171, arXiv:1604.07403, Bibcode:2016ApJ...826..171G, doi:10.3847/0004-637x/826/2/171, S2CID 119241004.

[Tetzlaff2011-10] 1 2 3 Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.

[SIMBAD-11] "4 Lac". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-28.

[Eggleton2008-12] Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.