Astronomy:HD 197911

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Short description: Star in the constellation Cepheus
HD 197911
Location of HD 197911 (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cepheus[1]
Right ascension  20h 43m 21.60554s[2]
Declination +63° 12′ 32.8418″[2]
Apparent magnitude (V) 7.669[3]
Characteristics
Spectral type B2V[1]
B−V color index +0.065[1]
Astrometry
Radial velocity (Rv)−3.80±3.5[4] km/s
Proper motion (μ) RA: −13.478[2] mas/yr
Dec.: −3.025[2] mas/yr
Parallax (π)1.0802 ± 0.0214[2] mas
Distance3,020 ± 60 ly
(930 ± 20 pc)
Absolute magnitude (MV)−2.73[5]
Details
Mass8.7[6] M☉
Radius9.218±0.461[3] R☉
Luminosity5,458[6] L☉
Surface gravity (log g)3.99[7] cgs
Temperature21,727[6] K
Rotational velocity (v sin i)95.4[8] km/s
Other designations
BD+62°1854, GC 28915, HD 197911, HIP 102274, SAO 19003, PPM 22349, TYC 4250-1529-1, GSC 04250-01529, 2MASS J20432160+6312329[9]
Database references
SIMBADHD 197911

HD 197911 (HIP 102274) is a bluish-white hued star in the deep northern constellation of Cepheus, close to the border with Draco and Cygnus. With an apparent magnitude of 7.669, it is too faint to be seen by the naked eye under most conditions, but readily visible using binoculars.[10] The star is located some 3,020 light-years (930 parsecs) distant according to Gaia EDR3 parallax measurements, but is moving closer to the Solar System at a heliocentric radial velocity of −3.8±3.5 km/s.

The star appears close to the reflection nebula and H II region[11] Sh2-130, alongside the A0-type star HD 197809 and G5-type star SAO 18999,[12] though the latter two stars are located much closer to Earth at 469 ly (144 pc)[13] and 198 ly (61 pc),[14] respectively. The nebula itself is situated at a distance of 600 pc (2,000 ly).[12]

Properties and origin

HD 197911 is a massive B-type star with the spectral type B2V, a mass 8.7 times that of the Sun and 9.2 times its radius. It is a runaway star traversing space at a peculiar velocity of 56.69 km/s. The star is thought to have once been part of a binary system, from which it was ejected as its companion ended its life in a supernova.[15]

Initially, the star was thought to have originated in an OB association called the Cepheus OB2 association, which it left 2–3 million years ago, when the association was 3–4 million years old. This aligned with the age of the Cepheus bubble, an annular structure of infrared emission, providing compelling evidence for the binary-supernova scenario, that is, that it was blasted out of a binary system by a companion going supernova.[16]

However, with updated astrometric data, it is now considered more likely that it formed in either Alessi-Teutsch 5 or NGC 7160, two star clusters that are each 12.5 and 9.0 million years old. Both origins are consistent with the initially proposed scenario.[15]

References

  1. ↑ 1.0 1.1 1.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 Kervella, Pierre; Arenou, Frédéric; Mignard, François; Thévenin, Frédéric (2019). "Stellar and substellar companions of nearby stars from Gaia DR2". Astronomy & Astrophysics (EDP Sciences) 623: A72. doi:10.1051/0004-6361/201834371. ISSN 0004-6361.  Record for this source at VizieR.
  4. ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  5. ↑ Melnik, A. M.; Dambis, A. K. (2020). "Distance scale for high-luminosity stars in OB associations and in field with Gaia DR2. Spurious systematic motions". Astrophysics and Space Science 365 (7): 112. doi:10.1007/s10509-020-03827-0. Bibcode: 2020Ap&SS.365..112M. 
  6. ↑ 6.0 6.1 6.2 Quintana, Alexis L.; Wright, Nicholas J.; Martínez García, Juan (2025). "A census of OB stars within 1 KPC and the star formation and core collapse supernova rates of the Milky Way". Monthly Notices of the Royal Astronomical Society 538 (3): 1367. doi:10.1093/mnras/staf083. Bibcode: 2025MNRAS.538.1367Q. 
  7. ↑ Thomas, G. F.; Battaglia, G.; Gran, F.; Fernández-Alvar, E.; Tsantaki, M.; Pancino, E.; Hill, V.; Kordopatis, G. et al. (2024). "SpectroTranslator: Deep-neural network algorithm for homogenising spectroscopic parameters". Astronomy and Astrophysics 690: A54. doi:10.1051/0004-6361/202450198. Bibcode: 2024A&A...690A..54T. 
  8. ↑ Jönsson, Henrik; Holtzman, Jon A.; Allende Prieto, Carlos; Cunha, Katia; García-Hernández, D. A.; Hasselquist, Sten; Masseron, Thomas; Osorio, Yeisson et al. (2020). "APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South". The Astronomical Journal 160 (3): 120. doi:10.3847/1538-3881/aba592. Bibcode: 2020AJ....160..120J. 
  9. ↑ "HD 197911". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+197911. 
  10. ↑ Zarenski, Ed (2004). "Limiting Magnitude in Binoculars". Cloudy Nights. http://www.cloudynights.com/documents/limiting.pdf. 
  11. ↑ Sharpless, Stewart (1959). "A Catalogue of H II Regions.". The Astrophysical Journal Supplement Series (American Astronomical Society) 4: 257. doi:10.1086/190049. ISSN 0067-0049. 
  12. ↑ 12.0 12.1 "Sh 2-130". http://galaxymap.org/cat/view/sharpless/130. 
  13. ↑ Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  14. ↑ Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  15. ↑ 15.0 15.1 Bhat, A.; Irrgang, A.; Heber, U. (2022). "The origin of early-type runaway stars from open clusters". Astronomy & Astrophysics (EDP Sciences) 663: A39. doi:10.1051/0004-6361/202142993. ISSN 0004-6361. 
  16. ↑ Hoogerwerf, R.; de Bruijne, J. H. J.; de Zeeuw, P. T. (2001). "On the origin of the O and B-type stars with high velocities". Astronomy & Astrophysics (EDP Sciences) 365 (2): 49–77. doi:10.1051/0004-6361:20000014. ISSN 0004-6361. 



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