HD 204018

Last updated
HD 204018
Microscopium constellation map.svg
Red circle.svg
location of HD 204018 (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Microscopium
A
Right ascension 21h 27m 01.62303s [1]
Declination −42° 32′ 52.5560″ [1]
Apparent magnitude  (V)5.58±0.01 [2]
B
Right ascension 21h 27m 01.75500s [3]
Declination −42° 32′ 55.0458″ [3]
Apparent magnitude  (V)8.09±0.01 [2]
Characteristics
A
Evolutionary stage subgiant [4]
Spectral type kA4 hF0 V mF6 [5]
U−B color index +0.15 [6]
B−V color index +0.39 [6]
B
Spectral type F8 V [7]
U−B color index +0.06 [7]
B−V color index +0.55 [7]
Astrometry
Radial velocity (Rv)18.3±2.8 [8]  km/s
A
Proper motion (μ)RA: −48.257  mas/yr [1]
Dec.: +13.160  mas/yr [1]
Parallax (π)18.489 ± 0.0498  mas [1]
Distance 176.4 ± 0.5  ly
(54.1 ± 0.1  pc)
Absolute magnitude  (MV)+1.74 [9]
B
Proper motion (μ)RA: −53.002  mas/yr [3]
Dec.: +15.410  mas/yr [3]
Parallax (π)18.5325 ± 0.0349  mas [3]
Distance 176.0 ± 0.3  ly
(54.0 ± 0.1  pc)
Absolute magnitude  (MV)+4.00 [7]
Details
A
Mass 1.65±0.11 [10]   M☉
Radius 2.55±0.13 [11]   R☉
Luminosity 15±1.2 [12]   L☉
Surface gravity (log g)3.86±0.08 [13]   cgs
Temperature 6,778 [14]   K
Rotational velocity (v sin i)85 [15]  km/s
Age 1.36±0.19 [1]   Gyr
B
Mass 1.02 [16]   M☉
Radius 1.09±0.21 [17]   R☉
Surface gravity (log g)4.29 [16]   cgs
Temperature 6,235±115 [18]   K
Metallicity [Fe/H]−0.11 [19]   dex
Age 3.46 [19]   Gyr
Other designations
69 G. Microscopii [20] , CD−43°14539, CPD−43°9451, GC  30021, HD  204018, HIP  105913, HR  8202, SAO  230692, WDS J21270-4233AB [21]
Database references
SIMBAD The system
A
B

HD 204018, also designated as HR 8202, is a visual binary located in the southern constellation Microscopium. The primary has an apparent magnitude of 5.58, [2] making it faintly visible to the naked eye under ideal conditions. The companion has an apparent magnitude of 8.09. [2] The system is located relatively close at a distance of 176 light years based on Gaia DR3 parallax measurements [1] [3] but is receding with a heliocentric radial velocity of 18.3  km/s . [8] At its current distance, HD 204018's combined brightness is diminished by 0.13 magnitudes due to interstellar dust. [22]

HD 204018A is an Am star with a stellar classification of kA4hF0 VmF6, [5] indicating that it has the calcium K-line of an A4 star, the hydrogen lines of a F0 main-sequence star and the metallic lines of a F6 star. It has 1.65 times the mass of the Sun [10] and 2.55 times the Sun's radius. [11] It radiates 15 times the luminosity of the Sun [12] from its photosphere at an effective temperature of 6,778  K , [14] giving it a yellowish-white hue. At an age of 1.5 billion years, HD 2014018A is estimated to be on the subgiant branch. [4] An alternate model places it on the main sequence at an age of 1,35 billion years. [1] The object spins at a moderate speed with a projected rotational velocity of 85  km/s . [15]

The companion is an F8 main sequence star [7] located 2+1⁄2" away along a position angle of 151°. [23] It has an angular diameter of 0.186±0.035  arcseconds , [18] which yields a radius of 1.09  R☉ at its estimated distance. [17] It has 102% times the mass of the Sun [16] and an effective temperature of 6,235  K . [18] HD 204018B is estimated to be 3.46 billion years old and is slightly metal deficient. [19]

There is a magnitude 12 co-moving companion located 295.3" away from the system along a position angle of 75°. [23] It is a red dwarf with an estimated spectral class of K6 and any orbit would take over a million years. [24]

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<span class="mw-page-title-main">HD 24479</span> Star in the constellation Camelopardalis

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<span class="mw-page-title-main">HD 203842</span> Star in the constellation Equuleus

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<span class="mw-page-title-main">HD 90132</span> Solitary White-hued star and high proper motion star

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<span class="mw-page-title-main">HD 26764</span> Star in the constellation Camelopardalis

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<span class="mw-page-title-main">HD 27022</span> Star in the constellation Camelopardalis

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HD 46588 is a star in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.44, allowing it to be faintly seen with the naked eye. The object is relatively close at a distance of only 59 light years but is receding with a heliocentric radial velocity of 15 km/s.

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

HD 68375 is a solitary star in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye with an apparent magnitude of 5.54 and is estimated to be 289 light years distant. However, it is receding with a heliocentric radial velocity of 4.33 km/s.

HD 221420 is a likely binary star system in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.81, allowing it to be faintly seen with the naked eye. The object is relatively close at a distance of 102 light years but is receding with a heliocentric radial velocity of 26.5 km/s.

HD 58425, also known as HR 2830, is an astrometric binary located in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye as an orang point of light at an apparent magnitude of 5.64. Based on parallax measurements from Gaia DR3, the system is estimated to be 470 light years away from Earth. It appears to be rapidly receding from the Sun, having a heliocentric radial velocity of 58.6 km/s. HD 58425 is listed as 54 Ursae Majoris in Johann Hevelius' catalogue, but this was dropped after the official IAU's official constellation borders were drawn.

HD 26670, also known as HR 1305, is a star located in the northern circumpolar constellation of Camelopardalis, the giraffe. The object has been designated as 26 H. Camelopardalis, but is not commonly used in modern times. It has an apparent magnitude of 5.70, allowing it to be faintly visible to the naked eye. Based on parallax measurements from Gaia DR3, the object is estimated to be 491 light years away from the Solar System. It appears to be slowly receding with a heliocentric radial velocity of 0.4 km/s.

HR 8526, also known as HD 212168, is the primary of a triple star located in the southern circumpolar constellation Octans. The star and its companion have apparent magnitudes of 6.12 and 9.36 respectively. The system is located relatively close at a distance of 76 light years based on Gaia DR3 parallax measurements, but is receding with a heliocentric radial velocity of 15 km/s.

<span class="mw-page-title-main">HD 196737</span> K-type giant; Microscopium

HD 196737, also designated as HR 7893, is a solitary orange hued star located in the southern constellation Microscopium. It has an apparent magnitude of 5.47, allowing it to be faintly visible to the naked eye. The object is located relatively close at a distance of 241 light years based on Gaia DR3 parallax measurements, but is receding with a heliocentric radial velocity of 14.2 km/s. At its current distance, HD 196737's brightness is diminished by 0.14 magnitudes due to interstellar dust. It has an absolute magnitude of 1.17.

HD 200779 is a solitary star located in the equatorial constellation Equuleus, the foal. It has an apparent magnitude of 8.27, making it readily visible in binoculars but not to the naked eye. The object is located relatively close at a distance of 49 light years based on Gaia DR3 parallax measurements, and it is approaching rapidly with a heliocentric radial velocity of −67 km/s. It is classified as a high proper motion star, with a total proper motion of 569 mas/yr.

References

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  4. 1 2 Corbally, C. J. (December 1984). "Close visual binaries. III - Parameters and evolutionary status". The Astronomical Journal. 89: 1887. Bibcode:1984AJ.....89.1887C. doi: 10.1086/113700 . ISSN   0004-6256.
  5. 1 2 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.
  6. 1 2 Feinstein, A. (April 1967). "Multicolor UBVRI observations of metallic-line stars". Publications of the Astronomical Society of the Pacific. 79: 184. Bibcode:1967PASP...79..184F. doi: 10.1086/128464 . eISSN   1538-3873. ISSN   0004-6280.
  7. 1 2 3 4 5 Corbally, C. J. (August 1984). "Close visual binaries. I - MK classifications". The Astrophysical Journal Supplement Series. 55: 657. Bibcode:1984ApJS...55..657C. doi: 10.1086/190973 . eISSN   1538-4365. ISSN   0067-0049.
  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. ↑ 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.
  10. 1 2 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. arXiv: astro-ph/9911002 . Bibcode:1999A&A...352..555A. ISSN   0004-6361.
  11. 1 2 Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants". 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.
  12. 1 2 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.
  13. ↑ 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 . eISSN   1538-3881. hdl: 1721.1/124721 . S2CID   166227927.
  14. 1 2 Schofield, Mathew; et al. (14 March 2019). "The Asteroseismic Target List for Solar-like Oscillators Observed in 2 minute Cadence with the Transiting Exoplanet Survey Satellite". The Astrophysical Journal Supplement Series. 241 (1): 12. arXiv: 1901.10148 . Bibcode:2019ApJS..241...12S. doi: 10.3847/1538-4365/ab04f5 . eISSN   1538-4365.
  15. 1 2 Huang, Su-Shu (September 1953). "A Statistical Study of the Rotation of the Stars". The Astrophysical Journal. 118: 285. Bibcode:1953ApJ...118..285H. doi: 10.1086/145751 . eISSN   1538-4357. ISSN   0004-637X.
  16. 1 2 3 Anders, F.; et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics. 658: A91. arXiv: 2111.01860 . Bibcode:2022A&A...658A..91A. doi: 10.1051/0004-6361/202142369 . eISSN   1432-0746. ISSN   0004-6361.
  17. 1 2 Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3 ed.). Birkhäuser. ISBN   3-540-29692-1.. The radius (R*) is given by:
  18. 1 2 3 Stevens, Daniel J.; Stassun, Keivan G.; Gaudi, B. Scott (29 November 2017). "Empirical Bolometric Fluxes and Angular Diameters of 1.6 Million Tycho-2 Stars and Radii of 350,000 Stars with Gaia DR1 Parallaxes". The Astronomical Journal. 154 (6): 259. arXiv: 1708.05025 . Bibcode:2017AJ....154..259S. doi: 10.3847/1538-3881/aa957b . eISSN   1538-3881. S2CID   119191064.
  19. 1 2 3 Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv: 1606.08814 . Bibcode:2012AstL...38..771G. doi: 10.1134/S1063773712120031 . eISSN   1562-6873. ISSN   1063-7737.
  20. ↑ 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.
  21. ↑ "HR 8202". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 21 December 2022.
  22. ↑ 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.
  23. 1 2 Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi: 10.1086/323920 . ISSN   0004-6256.
  24. ↑ Tokovinin, Andrei (23 February 2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series. 235 (1): 6. arXiv: 1712.04750 . Bibcode:2018ApJS..235....6T. doi: 10.3847/1538-4365/aaa1a5 . eISSN   1538-4365.
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