HD 190422

HD 190422, also known as HR 7674 or rarely 77 G. Telescopii, is a solitary star located in the southern constellation Telescopium. It has an apparent magnitude of +6.25,^[2] placing it near the limit for naked eye, even under ideal conditions. At its current distance, HD 190422's brightness is diminished by 0.11 magnitudes due to extinction from interstellar dust^[16] and it has an absolute magnitude of +4.41.^[6]

HD 190422

Location of HD 190422(circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Telescopium
Right ascension	20h 07m 35.09061s[1]
Declination	−55° 00′ 57.6492″[1]
Apparent magnitude (V)	6.25±0.01[2]
Characteristics
Spectral type	F9 V CH−0.4[3]
B−V color index	+0.53[4]
Astrometry
Radial velocity (Rv)	12.7±0.3[5] km/s
Proper motion (μ)	RA: +18.283 mas/yr[1] Dec.: +35.310 mas/yr[1]
Parallax (π)	41.5069 ± 0.028 mas[1]
Distance	78.58 ± 0.05 ly (24.09 ± 0.02 pc)
Absolute magnitude (MV)	+4.41[6]
Details
Mass	1.25[7] M☉
Radius	1.09±0.05[8] R☉
Luminosity	1.534+0.006 −0.005[1] L☉
Surface gravity (log g)	4.42[3] cgs
Temperature	6,235±100[9] K
Metallicity [Fe/H]	−0.13±0.03[10] dex
Rotation	27.2 d[11]
Rotational velocity (v sin i)	15.6±0.8[12] km/s
Age	400[13][3] Myr
Other designations
77 G. Telescopii[14], CD−55°8393, CPD−55°9317, GC 27884, HD 190422, HIP 99137, HR 7674, SAO 246444[15]
Database references
SIMBAD	data

The star is located relatively close at a distance of 79 light years based on Gaia DR3 parallax measurements^[1] but it is receding with a heliocentric radial velocity of 12.7 km/s.^[5] Approximately 1.6 million years ago, HD 190422 was located 7.806 parsecs (25.46 ly) away from the Sun.^[17]

HD 190422 has a stellar classification of F9 V CH−0.4,^[3] indicating that it is a F-type main-sequence star with a mild underabundance of the CH radical in its spectrum. It has 125% the mass of the Sun^[7] and 109% of the Sun's radius.^[8] It radiates 1.534 times the luminosity of the Sun^[1] from its photosphere at an effective temperature of 6,235 K,^[9] giving it a whitish-yellow hue. HD 190422 is slightly metal deficient with a metallicity of [Fe/H] = −0.13^[10] and it spins modestly with a projected rotational velocity of 15.6 km/s.^[12] The star is estimated to be 400 million years old,^[13][3] less than a tenth the age of the Sun.

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. 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.
3. Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2 June 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. eISSN 1538-3881. ISSN 0004-6256. S2CID 250741593.
4. Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J. S2CID 118307502.
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. eISSN 1562-6873. 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. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
7. Chandler, Colin Orion; McDonald, Iain; Kane, Stephen R. (17 February 2016). "The Catalog of Earth-Like Exoplanet Survey Targets (CELESTA): A Database of Habitable Zones Around Nearby Stars". The Astronomical Journal. 151 (3): 59. arXiv:1510.05666. Bibcode:2016AJ....151...59C. doi:10.3847/0004-6256/151/3/59. eISSN 1538-3881. S2CID 119246448.
8. Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants. Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
9. Casagrande, L.; Schönrich, R.; Asplund, M.; Cassisi, S.; Ramírez, I.; Meléndez, J.; Bensby, T.; Feltzing, S. (26 May 2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s): Improved astrophysical parameters for the Geneva-Copenhagen Survey⋆". Astronomy & Astrophysics. 530: A138. arXiv:1103.4651. Bibcode:2011A&A...530A.138C. doi:10.1051/0004-6361/201016276. eISSN 1432-0746. ISSN 0004-6361. S2CID 56118016.
10. Netopil, Martin (4 May 2017). "Metallicity calibrations for dwarf stars and giants in the Geneva photometric system". Monthly Notices of the Royal Astronomical Society. 469 (3): 3042–3055. arXiv:1705.00883. Bibcode:2017MNRAS.469.3042N. doi:10.1093/mnras/stx1077. eISSN 1365-2966. ISSN 0035-8711. S2CID 119034918.
11. Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B.; Kuhn, Rudolf B.; James, David; Gaudi, B. Scott (2018). "Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey". The Astronomical Journal. 155 (1): 39. arXiv:1711.03608. Bibcode:2018AJ....155...39O. doi:10.3847/1538-3881/aa9bf4. S2CID 119515775.
12. Ammler-von Eiff, M.; Reiners, A. (June 2012). "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?". Astronomy & Astrophysics. 542: A116. arXiv:1204.2459. Bibcode:2012A&A...542A.116A. doi:10.1051/0004-6361/201118724. eISSN 1432-0746. ISSN 0004-6361. S2CID 53666672.
13. Henry, Todd J.; Soderblom, David R.; Donahue, Robert A.; Baliunas, Sallie L. (January 1996). "A Survey of CA II H and K Chromospheric Emission in Southern Solar-Type Stars". The Astronomical Journal. 111: 439. Bibcode:1996AJ....111..439H. doi:10.1086/117796. ISSN 0004-6256. S2CID 120627407.
14. Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
15. "HD 190422". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved March 31, 2023.
16. 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.
17. Bailer-Jones, C. A. L. (19 February 2015). "Close encounters of the stellar kind". Astronomy & Astrophysics. 575: A35. arXiv:1412.3648. Bibcode:2015A&A...575A..35B. doi:10.1051/0004-6361/201425221. eISSN 1432-0746. ISSN 0004-6361. S2CID 59039482.