HD 21819

Last updated
HD 21819
Camelopardalis constellation map.svg
Red circle.svg
Location of HD 21819 on the map (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Camelopardalis [1]
Right ascension 03h 33m 39.06000s [2]
Declination +54° 58 29.4970 [2]
Apparent magnitude  (V)5.97±0.01 [3]
Characteristics
Evolutionary stage main sequence star [4]
Spectral type A3 V [5] or A2 Vp [6]
B−V color index +0.11 [7]
Astrometry
Radial velocity (Rv)−6.5±1.5 [8] km/s
Proper motion (μ)RA: −41.053 mas/yr [2]
Dec.: −0.357 mas/yr [2]
Parallax (π)13.1723±0.0317  mas [2]
Distance 247.6 ± 0.6  ly
(75.9 ± 0.2  pc)
Absolute magnitude  (MV)+1.62 [1]
Details
Mass 2.00+0.19
0.15
[9]   M
Radius 2.06±0.10 [10]   R
Luminosity 30.6+2.2
2.0
[4]   L
Surface gravity (log g)4.08 [11]   cgs
Temperature 9,000 [12]   K
Metallicity [Fe/H]−0.17 [11]   dex
Rotational velocity (v sin i)160±8 [6]  km/s
Age 737±102 [9]   Myr
Other designations
AG+54°370, BD+54°693, GC 4229, HD 21819, HIP 16599, HR 1073, SAO 24099, TIC 316848255 [13]
Database references
SIMBAD data

HD 21819, also designated as HR 1073, is a solitary star [14] located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.97, [3] making faintly visible to the naked eye under ideal conditions. The object is located relatively close at a distance of 248 light-years based on Gaia DR3 parallax measurements [2] and it is drifting closer with a heliocentric radial velocity of −6.5  km/s . [8] At its current distance, HD 21819's brightness is diminished by an interstellar extinction of 0.17 magnitudes [15] and it has an absolute magnitude of +1.62. [1]

HD 21819 has a stellar classification of A3 V, [5] indicating that it is an ordinary A-type main-sequence star that is generating energy via hydrogen fusion at its core. Abt & Morell (1995) gave a slightly hotter star of A2 Vp, [6] indicating that it is instead an Ap star with weak magnesium lines. It has twice the mass of the Sun [9] and 2.06 times the radius of the Sun. [10] It radiates 30.6 times the luminosity of the Sun [4] from its photosphere at an effective temperature of 9,000  K , [12] giving it a white hue when viewed in the night sky. HD 21819 is metal deficient with an iron abundance of [Fe/H] = −0.17 or 67.6% of the Sun's [11] and it is estimated to be 737 million years old, [9] having completed 55.7% of its main sequence lifetime. [4] Like most hot stars it spins rapidly, having a projected rotational velocity of 160  km/s . [6]

References

  1. 1 2 3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters . 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 6 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.
  3. 1 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.
  4. 1 2 3 4 Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv: 1201.2052 . Bibcode:2012A&A...537A.120Z. doi: 10.1051/0004-6361/201117691 . eISSN   1432-0746. ISSN   0004-6361. S2CID   55586789.
  5. 1 2 Cowley, A.; Cowley, C.; Jaschek, M.; Jaschek, C. (April 1969). "A study of the bright stars. I. A catalogue of spectral classifications". The Astronomical Journal. 74: 375. Bibcode:1969AJ.....74..375C. doi: 10.1086/110819 . ISSN   0004-6256. S2CID   121555804.
  6. 1 2 3 4 Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi: 10.1086/192182 . ISSN   0067-0049. S2CID   120495962.
  7. Häggkvist, L.; Oja, T. (1969). "Photoelectric BV photometry of 368 northern stars". Arkiv för Astronomi. 5: 125–135. Bibcode:1969ArA.....5..125H. ISSN   0004-2048.
  8. 1 2 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.
  9. 1 2 3 4 David, Trevor J.; Hillenbrand, Lynne A. (12 May 2015). "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv: 1501.03154 . Bibcode:2015ApJ...804..146D. doi: 10.1088/0004-637X/804/2/146 . eISSN   1538-4357. S2CID   33401607.
  10. 1 2 Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 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.
  11. 1 2 3 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 . eISSN   1432-0746. ISSN   0004-6361. S2CID   131780028.
  12. 1 2 Philip, A. G. D.; Egret, D. (May 1980). "An analysis of the Hauck-Mermillod catalogue of homogeneous four-color data. II". Astronomy and Astrophysics Supplement Series. 40: 199–205. Bibcode:1980A&AS...40..199P. ISSN   0365-0138.
  13. "HD 21819". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved December 24, 2023.
  14. De Rosa, R. J.; et al. (26 November 2013). "The VAST Survey – III. The multiplicity of A-type stars within 75 pc". Monthly Notices of the Royal Astronomical Society. 437 (2): 1216–1240. arXiv: 1311.7141 . Bibcode:2014MNRAS.437.1216D. doi: 10.1093/mnras/stt1932 . eISSN   1365-2966. ISSN   0035-8711. S2CID   88503488.
  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.