HD 193373

HD 193373 (HR 7771) is a solitary red hued star located in the equatorial constellation Delphinus. It has an apparent magnitude of 6.21,^[2] placing it near the limit for naked eye visibility. Parallax measurements place it 846 light years distant^[1] and it is currently receding with a heliocentric radial velocity of 22.7 km/s.^[5]

HD 193373

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Delphinus
Right ascension	20h 19m 29.2960s[1]
Declination	+13° 13′ 00.3571″[1]
Apparent magnitude (V)	6.21[2]
Characteristics
Evolutionary stage	AGB[3]
Spectral type	M1 III[4]
B−V color index	+1.63[2]
Astrometry
Radial velocity (Rv)	22.68±0.13[5] km/s
Proper motion (μ)	RA: −15.865 mas/yr[1] Dec.: −18.581 mas/yr[1]
Parallax (π)	3.8556 ± 0.0442 mas[1]
Distance	846 ± 10 ly (259 ± 3 pc)
Absolute magnitude (MV)	−0.46[6]
Details
Mass	1.77[7] M☉
Radius	57.5[8] R☉
Luminosity	592±16[9] L☉
Surface gravity (log g)	0.89[10] cgs
Temperature	3,884±122[8] K
Metallicity [Fe/H]	+0.08[10] dex
Other designations
AG+13°2092, BD+12°4289, HD 193373, HIP 100208, HR 7771, SAO 105961[11]
Database references
SIMBAD	data

This is an asymptotic giant branch star^[3] with a stellar classification of M1 III.^[4] In its current state, the object is fusing hydrogen and helium shells around an inert carbon core. HR 7771 has 177% the mass of the Sun^[7] but has expanded to an enlarged radius of 57.5 R_☉.^[8] It radiates at 592 times the luminosity of the Sun^[9] from its photosphere at an effective temperature of 3,884 K,^[8] giving a red hue. HD 193373 has an iron abundance 120% that of the Sun, making it slightly metal enriched.^[10]

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
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. 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.
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.
5. Famaey, B.; Pourbaix, D.; Frankowski, A.; Van Eck, S.; Mayor, M.; Udry, S.; Jorissen, A. (18 February 2009). "Spectroscopic binaries among Hipparcos M giants". Astronomy & Astrophysics. 498 (2): 627–640. arXiv:0901.0934. Bibcode:2009A&A...498..627F. doi:10.1051/0004-6361/200810698. eISSN 1432-0746. ISSN 0004-6361.
6. 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.
7. Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
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. ISSN 0004-6256.
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. Anders, F.; et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. ISSN 0004-6361.
11. "HR 7771". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved July 26, 2022.