HD 193556

HD 193556 (HR 7778) is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 6.17,^[2] making it visible to the naked eye under ideal conditions. Parallax measurements place the object at a distance of 467 light years^[1] and it is currently receding with a heliocentric radial velocity of 11.7 km/s.^[5]

HD 193556

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Delphinus
Right ascension	20h 20m 20.5234s[1]
Declination	+14° 34′ 09.3206″[1]
Apparent magnitude (V)	6.17±0.01[2]
Characteristics
Spectral type	G8 III[3]
U−B color index	+0.67[4]
B−V color index	+0.92[4]
Astrometry
Radial velocity (Rv)	11.7±0.3[5] km/s
Proper motion (μ)	RA: −3.887 mas/yr[1] Dec.: +5.610 mas/yr[1]
Parallax (π)	6.9878 ± 0.0252 mas[1]
Distance	467 ± 2 ly (143.1 ± 0.5 pc)
Absolute magnitude (MV)	+0.04[6]
Details
Mass	2.65[7] M☉
Radius	11.33[8] R☉
Luminosity	102[9] L☉
Surface gravity (log g)	2.76[10] cgs
Temperature	5,104[10] K
Metallicity [Fe/H]	+0.03[10] dex
Rotational velocity (v sin i)	1.5±1.2[11] km/s
Age	490[7] Myr
Other designations
AG+14°2187, BD+14°4263, FK5 3629, GC 28288, HD 193556, HIP 100274, HR 7778, SAO 105988[12]
Database references
SIMBAD	data

HD 193556 has a stellar classification of G8 III,^[3] indicating that it is a red giant. It has 2.65 times the mass of the Sun and is currently 490 million years old,^[7] having expanded to 11.33 times the radius of the Sun.^[8] It shines with a luminosity of 102 L_☉^[9] from its enlarged photosphere at an effective temperature of 5,104 K,^[10] giving it a yellow glow. HD 193556 has an iron abundance around solar level^[10] and spins leisurely with a poorly constrained projected rotational velocity of 1.5 km/s.^[11]

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. 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.
3. Harlan, E. A. (September 1969). "MK classifications for F and G-type stars. I." The Astronomical Journal. 74: 916. Bibcode:1969AJ.....74..916H. doi:10.1086/110881. ISSN 0004-6256.
4. Fernie, J. D. (May 1983). "New UBVRI photometry for 900 supergiants". The Astrophysical Journal Supplement Series. 52: 7. Bibcode:1983ApJS...52....7F. doi:10.1086/190856. eISSN 1538-4365. ISSN 0067-0049.
5. Gontcharov, G. A. (November 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. ISSN 1063-7737. S2CID 119231169.
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. ISSN 1063-7737. S2CID 255204555.
7. Dotter, Aaron; Chaboyer, Brian; Jevremović, Darko; Kostov, Veselin; Baron, E.; Ferguson, Jason W. (September 2008). "The Dartmouth Stellar Evolution Database". The Astrophysical Journal Supplement Series. 178 (1): 89–101. arXiv:0804.4473. Bibcode:2008ApJS..178...89D. doi:10.1086/589654. eISSN 1538-4365. ISSN 0067-0049.
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. Luck, R. Earle (25 August 2015). "Abundances in the Local Region. I. G and K Giants". The Astronomical Journal. 150 (3): 88. arXiv:1507.01466. Bibcode:2015AJ....150...88L. doi:10.1088/0004-6256/150/3/88. eISSN 1538-3881. ISSN 0004-6256. S2CID 118505114.
10. Liu, Y. J.; Tan, K. F.; Wang, L.; Zhao, G.; Sato, Bun'ei; Takeda, Y.; Li, H. N. (31 March 2014). "The Lithium Abundances of a Large Sample of Red Giants". The Astrophysical Journal. 785 (2): 94. arXiv:1404.1687. Bibcode:2014ApJ...785...94L. doi:10.1088/0004-637X/785/2/94. eISSN 1538-4357. ISSN 0004-637X.
11. de Medeiros, J. R.; Mayor, M. (November 1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement Series. 139 (3): 433–460. Bibcode:1999A&AS..139..433D. doi:10.1051/aas:1999401. ISSN 0365-0138.
12. "HD 193556". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved June 20, 2022.