HD 11928

HD 11928 (HR 564; NSV 15408) is a solitary star^[13] located in the northern constellation of Triangulum. It is faintly visible to the naked eye as a red-hued point of light with an apparent magnitude of 5.85.^[14] Gaia DR3 parallax measurements imply a distance of 530 light-years and it is drifting closer with a heliocentric radial velocity of −1.93 km/s.^[6] At its current distance, HD 11928's brightness is diminished by an interstellar extinction of 0.13 magnitudes^[15] and it has an absolute magnitude of +0.11.^[7]

HD 11928

Location of HD 11928 on the map (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Triangulum
Right ascension	01h 57m 43.74417s[1]
Declination	+27° 48′ 15.7579″[1]
Apparent magnitude (V)	5.84 - 5.85[2]
Characteristics
Evolutionary stage	AGB[3]
Spectral type	M2 III[4]
B−V color index	+1.60[5]
Variable type	suspected[2]
Astrometry
Radial velocity (Rv)	−1.93±0.22[6] km/s
Proper motion (μ)	RA: +12.974 mas/yr[1] Dec.: −60.043 mas/yr[1]
Parallax (π)	6.1432 ± 0.1953 mas[1]
Distance	530 ± 20 ly (163 ± 5 pc)
Absolute magnitude (MV)	+0.11[7]
Details
Radius	52.68[8] R☉
Luminosity	485±17[9] L☉
Surface gravity (log g)	1.024[10] cgs
Temperature	3,656±72[11] K
Other designations
NSV 15408, AG+27°211, BD+27°310, GC 2357, HD 11928, HIP 9132, HR 564, SAO 75048[12]
Database references
SIMBAD	data

HD 11928 has a stellar classification of M2 III,^[4] indicating that is an evolved M-type giant star. It is currently an asymptotic giant branch star that is generating energy via the fusion of hydrogen and helium shells around an inert carbon core. At present it has expanded to 52.68 times the radius of the Sun^[8] and it radiates 485 times the luminosity of the Sun^[9] from its photosphere at an effective temperature of 3,656 K.^[11]

In 1997, the Hipparcos satellite observed that the star varied from 5.89 to 5.93 in the Hipparcos passband.^[16] Further observations from Koen & Eyer reveal that HD 11928 flucates between 5.84 and 5.85 in the visual passband within 50.7 days.^[17] As of 2004 however, its variability has not been confirmed,^[18] but it is still suspected to be variable.

References

1. 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.
2. Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. eISSN 1562-6881. ISSN 1063-7729. S2CID 125853869.
3. Eggen, Olin J. (July 1992). "Asymptotic giant branch stars near the sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239. ISSN 0004-6256. S2CID 121672252.
4. Wilson, Ralph E.; Joy, Alfred H. (March 1950). "Radial Velocities of 2111 Stars". The Astrophysical Journal. 111: 221. Bibcode:1950ApJ...111..221W. doi:10.1086/145261. eISSN 1538-4357. ISSN 0004-637X. S2CID 122883647.
5. Haggkvist, L.; Oja, T. (1970). "Results of BV photometry 1969-70 (Uppsala refractor)". Private Communication. Bibcode:1970Priv.........0H. S2CID 231475662.
6. Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (January 2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
7. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
8. Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
9. 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.
10. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. eISSN 1365-2966. ISSN 0035-8711. S2CID 73594365.
11. van Belle, G. T.; Lane, B. F.; Thompson, R. R.; Boden, A. F.; Colavita, M. M.; Dumont, P. J.; Mobley, D. W.; Palmer, D.; Shao, M.; Vasisht, G. X.; Wallace, J. K.; Creech-Eakman, M. J.; Koresko, C. D.; Kulkarni, S. R.; Pan, X. P.; Gubler, J. (1999). "Radii and Effective Temperatures for G, K, and M Giants and Supergiants". The Astronomical Journal. 117 (1): 521–533. Bibcode:1999AJ....117..521V. doi:10.1086/300677. S2CID 18617983.
12. "HD 11928". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 11, 2024.
13. Eggleton, P. P.; Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. eISSN 1365-2966. ISSN 0035-8711. S2CID 14878976.
14. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361. S2CID 17128864.
15. Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711. S2CID 118879856.
16. Perryman, M. A. C.; Lindegren, L.; Kovalevsky, J.; Hoeg, E.; Bastian, U.; Bernacca, P. L.; Crézé, M.; Donati, F.; Grenon, M.; Grewing, M.; van Leeuwen, F. (July 1997). "The HIPPARCOS Catalogue". Astronomy and Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P. ISSN 0004-6361.
17. Koen, Chris; Eyer, Laurent (March 2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society. 331 (1): 45–59. arXiv:astro-ph/0112194. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x. eISSN 1365-2966. ISSN 0035-8711. S2CID 10505995.
18. Samus, N. N.; Durlevich, O. V. (November 2004). "VizieR Online Data Catalog: Combined General Catalogue of Variable Stars (Samus+ 2004)". VizieR Online Data Catalog: II/250. Bibcode:2004yCat.2250....0S.