Astronomy:HD 191220
Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
---|---|
Constellation | Octans |
Right ascension | 20h 24m 54.91771s[1] |
Declination | −83° 18′ 38.2301″[1] |
Apparent magnitude (V) | 6.14±0.01[2] |
Characteristics | |
Spectral type | A2/3 mA8-F0[3] |
U−B color index | +0.13[4] |
B−V color index | +0.20[4] |
Astrometry | |
Radial velocity (Rv) | 0.1±1.3[5] km/s |
Proper motion (μ) | RA: +23.223[1] mas/yr Dec.: +6.228[1] mas/yr |
Parallax (π) | 13.331 ± 0.0247[1] mas |
Distance | 244.7 ± 0.5 ly (75.0 ± 0.1 pc) |
Absolute magnitude (MV) | +1.76[6] |
Details | |
Mass | 2.06±0.40[7] M☉ |
Radius | 2.17±0.06[8] R☉ |
Luminosity | 15.57[9] L☉ |
Surface gravity (log g) | 4.12±0.06[10] cgs |
Temperature | 7,706±126[11] K |
Metallicity [Fe/H] | −0.02[12] dex |
Age | 979±166[1] Myr |
Other designations | |
Database references | |
SIMBAD | data |
HD 191220, also known as HR 7698, is a solitary white hued star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.14,[2] placing it near the limit for naked eye visibility. The object is located relatively close at a distance of 245 light years based on Gaia DR3 parallax measurements[1] but is slowly receding with a heliocentric radial velocity of 0.1 km/s.[5] At its current distance, HD 191220's brightness is diminished by 0.22 magnitudes due to interstellar dust.[14]
This is a chemically peculiar Am star[15] with a stellar classification of A2/3mA8-F0,[3] an A-type star with the metallic lines of a star with a class of A8-F0. It has double the mass of the Sun and 2.2 times its girth.[7] It radiates 15.57 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 7,706 K.[11] HD 191220 is estimated to be nearly a billion years old[12] and has a near solar metallicity — what astronomers dub a star's abundance of chemical elements heavier than helium.[12]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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.
- ↑ 2.0 2.1 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H.
- ↑ 3.0 3.1 Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°. Bibcode: 1975mcts.book.....H.
- ↑ 4.0 4.1 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.
- ↑ 5.0 5.1 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. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode: 2006AstL...32..759G.
- ↑ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A.
- ↑ 7.0 7.1 Stassun, Keivan G.; Oelkers, Ryan J.; Pepper, Joshua et al. (20 August 2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal 156 (3): 102. doi:10.3847/1538-3881/aad050. Bibcode: 2018AJ....156..102S.
- ↑ Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S.
- ↑ 9.0 9.1 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (21 November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars: Parameters and IR excesses from Hipparcos". Monthly Notices of the Royal Astronomical Society 427 (1): 343–357. doi:10.1111/j.1365-2966.2012.21873.x. ISSN 0035-8711. Bibcode: 2012MNRAS.427..343M.
- ↑ Allende Prieto, C.; Lambert, D. L. (December 1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics 352: 555–562. ISSN 0004-6361. Bibcode: 1999A&A...352..555A.
- ↑ 11.0 11.1 Bai, Yu; Liu, JiFeng; Bai, ZhongRui; Wang, Song; Fan, DongWei (2 August 2019). "Machine-learning Regression of Stellar Effective Temperatures in the Second Gaia Data Release". The Astronomical Journal 158 (2): 93. doi:10.3847/1538-3881/ab3048. Bibcode: 2019AJ....158...93B.
- ↑ 12.0 12.1 12.2 Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters 38 (12): 771–782. doi:10.1134/S1063773712120031. ISSN 1063-7737. Bibcode: 2012AstL...38..771G.
- ↑ "HD 191220". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+191220.
- ↑ 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. doi:10.1093/mnras/stx2219. ISSN 0035-8711. Bibcode: 2017MNRAS.472.3805G.
- ↑ Renson, P.; Manfroid, J. (19 March 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy & Astrophysics 498 (3): 961–966. doi:10.1051/0004-6361/200810788. ISSN 0004-6361. Bibcode: 2009A&A...498..961R.
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