HD 219617

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HD 219617
Observation data
Epoch J2000       Equinox J2000
Constellation Aquarius
Right ascension 23h 17m 05.0438s [1]
Declination −13° 51′ 03.5971″ [1]
Apparent magnitude  (V)8.14 [1]
Characteristics
HD 219617A
Evolutionary stage subdwarf star
Spectral type sdF5[ citation needed ]
HD 219617B
Spectral type sdF6[ citation needed ]
Astrometry
Radial velocity (Rv)13.28±0.35 [2]  km/s
Parallax (π)15.08 ± 1.8  mas [3]
Distance approx. 220  ly
(approx. 66  pc)
Absolute magnitude  (MV)3.64 [4]
Orbit [3]
PrimaryHD 219617A
CompanionHD 219617B
Period (P)388+34
−24 y
Semi-major axis (a)0.957+0.053
−0.041″
Eccentricity (e)0.464+0.040
−0.041
Inclination (i)86.93+0.07
−0.06°
Details
HD 219617A
Mass 1.126+0.004
−0.005 [3]   M☉
Luminosity 5825 [5]   L☉
Surface gravity (log g)4.30 [5]   cgs
Temperature 5825 [5]   K
Metallicity [Fe/H]−1.45 [6]   dex
Rotational velocity (v sin i)6.2 [7]  km/s
Age 16.14+0.81
−0.78 [8]   Gyr
HD 219617B
Mass 1.068±0.004 [3]   M☉
Surface gravity (log g)4.30 [5]   cgs
Other designations
BD−14 6437, HIP  114962, ADS  16644, 2MASS J23170501-1351046, Gaia EDR3 2411728178376670976 [1]
HD 219617A: TYC 5827-1181-2
HD 219617B: TYC 5827-1181-1
Database references
SIMBAD data

HD 219617 is a binary star system some 220 light-years away from the Solar System in the constellation Aquarius. It is composed of two metal-poor F-type subdwarf stars orbiting each other in a 388-year orbit. [3] Another theory suggests that the binary star is composed of subgiant stars. [4] Unlike many halo stars, which exhibit an excess of alpha elements relative to iron, HD 219617 is depleted in iron peak and alpha elements, although alpha elements concentrations are poorly constrained. [8] The stellar chemical composition is peculiar, being relatively oxygen-enriched [9] and extremely depleted in neutron capture elements. [6] The helium fraction of the binary star at present cannot be reliably determined, and appears to be near the primordial helium abundance. [10]

The binary star HD 219617 is part of the hierarchical triple system LDS 6393, together with the red subdwarf VB 12 (LHS 541) of spectral class sdM3 [11] at a projected separation of 19″ (1,200 AU). [4] VB 12 also has several peculiarities. [4] The star system belongs kinematically to the halo stars. Additional stellar components of the star system are suspected. [3]

The binary nature of HD 219617 has been known since the 19th century, but uncertainties in measurement and a stellar conjunction in 1920 precluded determining even an approximate orbit until 1991. [12] [10] Then in 2017, the orbit was measured accurately, as separation between the stars increased. [3]

Related Research Articles

<span class="mw-page-title-main">Subdwarf</span> Star of luminosity class VI under the Yerkes spectral classification system

A subdwarf, sometimes denoted by "sd", is a star with luminosity class VI under the Yerkes spectral classification system. They are defined as stars with luminosity 1.5 to 2 magnitudes lower than that of main-sequence stars of the same spectral type. On a Hertzsprung–Russell diagram subdwarfs appear to lie below the main sequence.

<span class="mw-page-title-main">Metallicity</span> Relative abundance of heavy elements in a star or other astronomical object

In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word "metals" as a convenient short term for "all elements except hydrogen and helium". This word-use is distinct from the conventional chemical or physical definition of a metal as an electrically conducting solid. Stars and nebulae with relatively high abundances of heavier elements are called "metal-rich" in astrophysical terms, even though many of those elements are nonmetals in chemistry.

<span class="mw-page-title-main">HD 10307</span> Binary star system in the constellation Andromeda

HD 10307 is a spectroscopic binary star in the constellation Andromeda. The primary is similar to the Sun in mass, temperature and metal content. situated about 42 light-years from Earth Its companion, HR 483 B, is a little-studied red dwarf.

<span class="mw-page-title-main">Mu Cassiopeiae</span>

Mu Cassiopeiae, Latinized from μ Cassiopeiae, is a binary star system in the constellation Cassiopeia. This system shares the name Marfak with Theta Cassiopeiae, and the name was from Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". It is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.16. The system is located at a distance of 24.6 light years from the Sun based on parallax, and is moving closer with a high radial velocity of −98 km/s. This star will move into the constellation Perseus around 5200 AD.

HD 11506 is a star in the equatorial constellation of Cetus. It has a yellow hue and can be viewed with a small telescope but is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.51. The distance to this object is 167 light years based on parallax, but it is drifting closer to the Sun with a radial velocity of −7.5 km/s. It has an absolute magnitude of 3.94.

HD 115404 is a binary star system located in the constellation Coma Berenices. Parallax measurements made by Hipparcos put the system at 36 light-years, or 11 parsecs, away. The combined apparent magnitude of the system is 6.52, with the magnitudes of the components being 6.66 and 9.50.

<span class="mw-page-title-main">V538 Aurigae</span> Single K-type star in constellation Auriga

V538 Aurigae is a single star in the northern constellation of Auriga. With an apparent visual magnitude of 6.23, this star requires good dark sky conditions to view with the naked eye. It is located at a distance of 40.0 light-years (12.3 pc) from Sun based on parallax. The star is drifting further away with a radial velocity of 0.9 km/s. It is a member of the Local Association, and is most likely a thin disk star.

26 Draconis is a triple star system in the constellation Draco, located 46 light years from the Sun. Two of the system components, A and B, form a spectroscopic binary that completes an orbit every 76 years. The composite spectral classification of the AB pair is G0V, which decomposes to individual spectral types F9V and K3V. A 1962 study estimated the masses of these two stars as 1.30 and 0.83 times the mass of the Sun, respectively. The stars are considered moderately metal-poor compared to the Sun, which means they have a lower proportion of elements other than hydrogen or helium.

Pi Chamaeleontis, its name Latinized from π Chamaeleontis, is a binary star system located in the southern circumpolar constellation of Chamaeleon. It is dimly visible to the naked eye with an apparent visual magnitude of 5.64. Parallax measurements by Hipparcos put the system approximately 135 light-years away. It is drifting closer with a radial velocity of −10 km/s.

HD 79498 is a primary of the star system located 159 light years away in the constellation Cancer. This G5 main sequence star has an apparent magnitude of 8.0 and is about the same size and mass as the Sun. It has a higher than solar abundance of elements other than hydrogen and helium; what astronomers term a metal-rich star.

μ Cygni, Latinised as Mu Cygni, is a binary star system in the northern constellation of Cygnus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.49. The system is located 72 light years distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +17 km/s.

15 Eridani is a binary star system in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.875. Based upon parallax measurements, the system is located around 260 light years away from the Sun. It is moving further from the Earth with a heliocentric radial velocity of 24 km/s.

99 Herculis is the Flamsteed designation for a binary star system in the northern constellation of Hercules. It has the Bayer designation b Herculis, while 99 Herculis is the Flamsteed designation. This system has an apparent visual magnitude of 5.1, which, according to the Bortle scale, makes it faintly visible to the naked eye from suburban skies. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.064″, corresponding to a physical distance of about 51.0 ly (15.6 pc) from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of +1.7 km/s.

HD 219623 is a solitary star in the northern circumpolar constellation of Cassiopeia. HD 219623 is its Henry Draper Catalogue designation. It has an apparent visual magnitude of 5.59, which lies in the brightness range that is visible to the naked eye. According to the Bortle scale, it can be observed from dark suburban skies. Parallax measurements place it at an estimated distance of around 67.2 light years. It has a relatively high proper motion, advancing 262 mas per year across the celestial sphere.

c Ursae Majoris is the Bayer designation for a double-lined spectroscopic binary star system in the northern constellation of Ursa Major. It has an apparent visual magnitude of 5.18, which indicates that is visible to the naked eye. Parallax measurements yield an estimated distance of 66 light years from the Sun. The star is moving closer to the Earth with a heliocentric radial velocity of −14 km/s.

Phi Phoenicis, Latinized from φ Phoenicis, is a binary star system in the southern constellation of Phoenix. It is faintly visible to the naked eye with an apparent visual magnitude of 5.1. Based upon an annual parallax shift of 10.185 mas as seen from Earth, it is located approximately 320 light years from the Sun. It is moving away with a heliocentric radial velocity of 10.4 km/s.

HD 146389, is a star with a yellow-white hue in the northern constellation of Hercules. The star was given the formal name Irena by the International Astronomical Union in January 2020. It is invisible to the naked eye with an apparent visual magnitude of 9.4 The star is located at a distance of approximately 446 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −9 km/s. The star is known to host one exoplanet, designated WASP-38b or formally named 'Iztok'.

<span class="mw-page-title-main">NY Virginis</span> Binary star in the constellation Virgo

NY Virginis is a binary star about 1,940 light-years away. The primary belongs to the rare class of subdwarf B stars, being former red giants with their hydrogen envelope completely stripped by a stellar companion. The companion is a red dwarf star. The binary nature of NY Virginis was first identified in 1998, and the extremely short orbital period of 0.101016 d, together with brightness variability on the timescale of 200 seconds was noticed, resulting in the identification of the primary star as a B-type subdwarf in 2003. Under a proposed classification scheme for hot subdwarfs it would be class sdB1VII:He1. This non-standard system indicates that it is a "normal" luminosity for a hot subdwarf and that the spectrum is dominated by hydrogen rather than helium.

HD 72945 and HD 72946 form a co-moving star system in the northern constellation of Cancer. HD 72945 is a binary star that is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.91. At an angular separation of 10.10″ is the fainter companion star HD 72946 at magnitude 7.25. It is being orbited by a brown dwarf. The system as a whole is located at a distance of approximately 84 light years from the Sun based on parallax measurements.

References

  1. 1 2 3 4 "HD 219617". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2021-06-10.
  2. ↑ Navarrete, Camila; Chanamé, Julio; Ramírez, Iván; Meza, Andrés; Anglada-Escudé, Guillem; Shkolnik, Evgenya (2015), "The Kapteyn Moving Group is Not Tidal Debris from ω Centauri", The Astrophysical Journal, 808 (1): 103–126, arXiv: 1506.02041 , Bibcode:2015ApJ...808..103N, doi:10.1088/0004-637X/808/1/103, S2CID   119021423
  3. 1 2 3 4 5 6 7 Mendez, Rene A.; Claveria, Ruben M.; Orchard, Marcos E.; Silva, Jorge F. (2017), "Orbits for 18 Visual Binaries and Two Double-line Spectroscopic Binaries Observed with HRCAM on the CTIO SOAR 4 m Telescope, Using a New Bayesian Orbit Code Based on Markov Chain Monte Carlo", The Astronomical Journal, 154 (5): 187, arXiv: 1709.06582 , Bibcode:2017AJ....154..187M, doi:10.3847/1538-3881/aa8d6f, S2CID   55695873
  4. 1 2 3 4 Krawchuk, C. A. P.; Dawson, P. C.; De Robertis, M. M. (2000), "Fundamental Parameters of Low-Mass Stars from Broadband Photometry. I. Method and First Results", The Astronomical Journal, 119 (4): 1956–1967, Bibcode:2000AJ....119.1956K, doi:10.1086/301292
  5. 1 2 3 4 Takeda, Yoichi; Takada-Hidai, Masahide (2011), "Chromospheres in Metal-Poor Stars Evidenced from the He I 10830Å Line", Publications of the Astronomical Society of Japan, 63: 547, arXiv: 1102.3210 , Bibcode:2011PASJ...63S.547T, doi:10.1093/pasj/63.sp2.S547
  6. 1 2 Fishlock, C. K.; Yong, D.; Karakas, A. I.; Alves-Brito, A.; Meléndez, J.; Nissen, P. E.; Kobayashi, C.; Casey, A. R. (2017), "Sc and neutron-capture abundances in Galactic low- and high-α field halo stars", Monthly Notices of the Royal Astronomical Society, 466 (4): 4672, arXiv: 1701.02423 , Bibcode:2017MNRAS.466.4672F, doi:10.1093/mnras/stx047
  7. ↑ De Medeiros, J. R.; Silva, J. R. P.; Do Nascimento Jr, J. D.; Canto Martins, B. L.; Da Silva, L.; Melo, C.; Burnet, M. (2006), "A catalog of rotational and radial velocities for evolved stars", Astronomy & Astrophysics, 458 (3): 895–898, arXiv: astro-ph/0608248 , doi:10.1051/0004-6361:20065642, S2CID   119343731
  8. 1 2 Ge, Z. S.; Bi, S. L.; Chen, Y. Q.; Li, T. D.; Zhao, J. K.; Liu, K.; Ferguson, J. W.; Wu, Y. Q. (2016), "Ages of 70 Dwarfs of Three Populations in the Solar Neighborhood: Considering O and C Abundances in Stellar Models", The Astrophysical Journal, 833 (2): 161, arXiv: 1612.01622 , Bibcode:2016ApJ...833..161G, doi:10.3847/1538-4357/833/2/161, S2CID   119190116
  9. ↑ Ramírez, I.; Meléndez, J.; Chanamé, J. (2012), "Oxygen Abundances in Low- and High-α Field Halo Stars and the Discovery of Two Field Stars Born in Globular Clusters", The Astrophysical Journal, 757 (2): 164, arXiv: 1208.3675 , Bibcode:2012ApJ...757..164R, doi:10.1088/0004-637X/757/2/164, S2CID   118520207
  10. 1 2 Smak, J. (1987), "On the helium content of the subdwarf binary ADS 16644", Acta Astronomica, 37: 357, Bibcode:1987AcA....37..357S
  11. ↑ Rajpurohit, A. S.; Reylé, C.; Allard, F.; Homeier, D.; Bayo, A.; Mousis, O.; Rajpurohit, S.; Fernández-Trincado, J. G. (2016), "Spectral energy distribution of M-subdwarfs: A study of their atmospheric properties", Astronomy and Astrophysics, 596: A33, arXiv: 1609.07062 , Bibcode:2016A&A...596A..33R, doi:10.1051/0004-6361/201526776, S2CID   119305968
  12. ↑ Heintz, W. D. (1991), "Orbits of visual binaries", Astronomy and Astrophysics Supplement Series, 90: 311, Bibcode:1991A&AS...90..311H
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