HD 861

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HD 861
Cassiopeia constellation map.svg
Red circle.svg
Location of HD 861 (circled)
Observation data
Epoch J2000 [1]        Equinox J2000 [1]
Constellation Cassiopeia [2]
Right ascension 00h 13m 12.73037s [3]
Declination +62° 02′ 27.1598″ [3]
Apparent magnitude  (V)6.622 [4]
Characteristics
Spectral type A2m [5] + GV [6]
B−V color index +0.208 [4]
Astrometry
Radial velocity (Rv)8.80±6.28 [3] km/s
Proper motion (μ)RA: 72.804 [3] mas/yr
Dec.: -19.171 [3] mas/yr
Parallax (π)8.0883±0.0269  mas [3]
Distance 403 ± 1  ly
(123.6 ± 0.4  pc)
Absolute magnitude  (MV)1.30 (A), 5.62 (B) [6]
Orbit [6]
PrimaryHD 861 A
CompanionHD 861 B
Period (P)15.9696 d
Eccentricity (e)0.124
Details [6]
HD 861 A
Mass 2.04  M☉
Radius 2.775 ± 0.139 [7]   R☉
Surface gravity (log g)4.00  cgs
Temperature 8100  K
Metallicity [Fe/H]0.44  dex
Rotational velocity (v sin i)37 km/s
Age 724  Myr
HD 861 B
Mass 0.95  M☉
Surface gravity (log g)4.5  cgs
Temperature 5500  K
Other designations
AG+61°8, BD+61°16, GC 233, HD 861, HIP 1063, SAO 11044, PPM 12017, TIC 83612641, TYC 4018-687-1, GSC 04018-00687, 2MASS J00131272+6202271, Renson 130 [1]
Database references
SIMBAD HD 861

HD 861 is a spectroscopic binary star system in the deep northern constellation of Cassiopeia. With an apparent magnitude of 6.622, the star is faintly visible to the naked eye under very dark skies and readily visible using binoculars. [8] It is located approximately 403 light-years (124 parsecs) distant according to Gaia DR3 parallax measurements, and is moving further away at a heliocentric radial velocity of 8.80 km/s.

Contents

Stellar properties

The primary star is a typical Am star, enriched in iron and especially so in barium but depleted in carbon, oxygen and calcium. At an age of 724 million (108.86) years, it is currently a main-sequence star fusing hydrogen into helium at its core. It will continue to do so for the next 320 million years until it runs out of core hydrogen at 1.05 billion (109.02) years old, at which point it will leave the main sequence and enter the subgiant phase. [6]

The secondary star is a G-type main-sequence star slightly less massive than the Sun and less than half as luminous. [6]

Orbit

The orbital properties of the companion were first determined in 1971 by Acker, with an orbital period of 11.2153 days and an eccentricity of 0.22. [9] In 2002, however, Debernardi found an entirely different set of orbital parameters in his PhD thesis and also discovered the stellar spectra of the secondary star. This new orbit has a longer period of 15.9696 days and a lower eccentricity of 0.124. This was backed up by Budaj et al., [10] who also independently found the secondary spectra and obtained a mass ratio between the two stars that agreed with Debernardi's research. [6]

References

  1. 1 2 3 "HD 861". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 5 November 2024.
  2. ↑ 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.
  3. 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.
  4. 1 2 Høg, E.; et al. (February 2000). "The Tycho-2 Catalogue of the 2.5 Million Brightest Stars". Astronomy and Astrophysics. 355 (1): L27 –L30. Bibcode:2000A&A...355L..27H.
  5. ↑ Abt, H.A. (2009). "MK classifications of spectroscopic binaries". VizieR On-line Data Catalog. Centre de Donnees Strasbourg (CDS). Bibcode:2009yCat..21800117A. doi:10.26093/CDS/VIZIER.21800117 . Retrieved 5 November 2024.
  6. 1 2 3 4 5 6 7 Iliev, I. K.; et al. (1 August 2006). "Abundance analysis of Am binaries and search for tidally driven abundance anomalies - II. HD 861, HD 18778, HD 20320, HD 29479, HD 96528 and HD 108651". Monthly Notices of the Royal Astronomical Society. 370 (2). Oxford University Press (OUP): 819–827. Bibcode:2006MNRAS.370..819I. doi: 10.1111/j.1365-2966.2006.10513.x . ISSN   0035-8711. Creative Commons by small.svg  This article incorporates textfrom this source, which is available under the CC BY 4.0 license.
  7. ↑ Kervella, Pierre; et al. (2019). "Stellar and substellar companions of nearby stars from Gaia DR2". Astronomy & Astrophysics. 623. EDP Sciences: A72. arXiv: 1811.08902 . Bibcode:2019A&A...623A..72K. doi: 10.1051/0004-6361/201834371 . ISSN   0004-6361. Record for this source at VizieR.
  8. ↑ Zarenski, Ed (2004). "Limiting Magnitude in Binoculars" (PDF). Cloudy Nights. Archived (PDF) from the original on 21 July 2011. Retrieved 6 May 2011.
  9. ↑ Acker, A. (September 1971). "Orbital elements of the spectroscopic binaries HD 24733 and HD 861". Astronomy & Astrophysics (in French). 14: 189. Bibcode:1971A&A....14..189A.
  10. ↑ Budaj, J.; Iliev, I. Kh.; Fenovcik, M.; Barzova, I.; Richards, M. T.; Geordzheva, E. (12 March 2004). "Discovery of the Secondary in the Spectrum of the SB1 System HD 861". Information Bulletin on Variable Stars. 5509 (1). International Astronomical Union. Bibcode:2004IBVS.5509....1B. ISSN   0374-0676.
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