19 Draconis

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19 Draconis
19 Draconis.jpg
19 Draconis in optical light
Observation data
Epoch J2000        Equinox J2000
Constellation Draco
Right ascension 16h 56m 01.68925s [1]
Declination +65° 08 05.2631 [1]
Apparent magnitude  (V)4.89 [2]
Characteristics
Spectral type F8V [3]
U−B color index -0.03 [2]
B−V color index +0.485 [2]
Astrometry
Radial velocity (Rv)−21.00 ± 0.8 [4]  km/s
Proper motion (μ)RA: 237.79 [1]   mas/yr
Dec.: 50.84 [1]   mas/yr
Parallax (π)65.54 ± 0.33  mas [1]
Distance 49.8 ± 0.3  ly
(15.26 ± 0.08  pc)
Absolute magnitude  (MV)3.98 [5]
Orbit [5]
Period (P)52.1089 ± 0.0001 d
Semi-major axis (a)20.0 mas
Eccentricity (e)0.2221 ± 0.0002
Inclination (i)90.5 ± 2.2°
Longitude of the node (Ω)23.5 ± 2.0°
Periastron epoch (T)JD 2453427.880 ± 0.007
Argument of periastron (ω)
(secondary)
338.46 ± 0.05°
Semi-amplitude (K1)
(primary)
17.465 ± 0.004 km/s
Details [5]
19 Dra A
Mass 1.04  M
Radius 1.2  R
Luminosity 2.02  L
Temperature 6298 ± 80  K
Metallicity Z = 0.013 ± 0.004
Age 4.7  Gyr
19 Dra B
Mass 0.37  M
Radius 0.3  R
Luminosity0.02  L
Temperature ~3963 [note 1]   K
Other designations
BD+65° 1157, GJ  648, HD  153597, HIP  82860, HR  6315, SAO  17281
Database references
SIMBAD data
ARICNS data

19 Draconis, also known as h Draconis, is a star system in the constellation Draco. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.89. [2] Based on its parallax, the system is located about 49.8 light-years (15.26 parsecs) away. [1] It is moving closer to the Earth with a heliocentric radial velocity of −21 km/s. [4]

This is a binary star system with an orbital period of 52.1 days and an eccentricity of 0.22. Only the primary star can be directly detected, via Doppler shifts or perturbations around the system's barycenter. Using spectroscopy and astrometry, the nature of the secondary star can be inferred. The primary star is an F-type main-sequence star with a stellar classification of F8V, [3] 4% more massive than the Sun. Its surface temperature is about 6,298 K, and it emits just over twice the amount of energy that the Sun does. The secondary is only 37% as massive as the Sun, and its luminosity is only 2% that of the Sun. The system is about 4.7 billion years old. [5]

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

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<span class="mw-page-title-main">Iota Canis Majoris</span> Variable star in the constellation Canis Major

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Psi1 Draconis Star in the constellation Draco

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Pi2 Cygni, Latinized from π2 Cygni, is a triple star system in the northern constellation of Cygnus. It is visible to the naked eye about 2.5° east-northeast of the open cluster M39, having an apparent visual magnitude of 4.24. Based upon an annual parallax shift of 2.95 mas, it is located at a distance of roughly 1,100 light years from the Sun.

<span class="mw-page-title-main">Theta Draconis</span> Binary star system in the constellation Draco

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Zeta Eridani is a binary star in the constellation of Eridanus. With an apparent visual magnitude of 4.80, it is visible to the naked eye on a clear dark night. Based on parallax measurements taken during the Hipparcos mission, it is approximately 110 light-years from the Sun.

<span class="mw-page-title-main">Sigma Geminorum</span> Binary star system in the constellation Gemini

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Chi Geminorum is a binary star system in the constellation Gemini, near the western border with Cancer. It can be viewed with the naked eye on a dark night, having an apparent visual magnitude of 4.98. Based upon an annual parallax shift of 12.73 mas, it is located roughly 260 light years from the Sun.

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20 Persei is a visual binary star in the northern constellation of Perseus, a few degrees from Pi Persei. It is visible to the naked eye as a dim, yellow-white hued point of light with a combined apparent visual magnitude of 5.343. The system is located around 230 light-years (71 pc) away from the Sun, based on its parallax. It is receding from the Earth with a heliocentric radial velocity of +6 km/s.

ω Leonis, is a star system located in the zodiac constellation of Leo. It is visible to the naked eye in the absence of light pollution, with an apparent visual magnitude of about 5.4. The distance to this star, as determined using parallax measurements, is around 108 light years from the Sun. Because of its location close to the ecliptic, it is subject to being obscured by the Moon, and potentially by planets.

Rho1 Eridani , is a star located in the constellation Eridanus. It forms an asterism with the stars Rho2 and Rho3 Eridani, south of Cetus, in the upper north east portion of Eridanus. The star has an apparent visual magnitude of 5.75, which indicates it is faintly visible to the naked eye on a clear, dark night. Based upon parallax measurements made with the Hipparcos satellite, this star is roughly 320 light years away from the Sun. Judging from changes to its proper motion, there is a chance that this is an astrometric binary.

Lambda Crateris, Latinized from λ Crateris, is the Bayer designation for a suspected binary star system in the southern constellation of Crater. With an annual parallax shift of 23.32 milliarcsecond as observed from Earth, it is located around 140 light years from the Sun. It is faintly visible to the naked eye with an apparent visual magnitude of 5.08.

References

  1. 1 2 3 4 5 6 van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. 1 2 3 4 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  3. 1 2 Abt, Helmut A. (2009). "MK Classifications of Spectroscopic Binaries". The Astrophysical Journal Supplement. 180 (1): 117–18. Bibcode:2009ApJS..180..117A. doi:10.1088/0067-0049/180/1/117. S2CID   122811461.
  4. 1 2 Gontcharov, G. A. (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. S2CID   119231169.
  5. 1 2 3 4 Wang, Xiaoli; Ren, Shulin; Fu, Yanning (2015). "Self-Consistent Orbits and Physical Properties for Eight Single-Lined Spectroscopic Binaries". The Astronomical Journal. 150 (4): 110. Bibcode:2015AJ....150..110W. doi: 10.1088/0004-6256/150/4/110 .

Notes

  1. From L = 4πR2σTeff4, rearranging to make Teff = (L / 4πR2σ)1/4. Where L is the luminosity, R is the radius, Teff is the effective surface temperature and σ is the Stefan–Boltzmann constant.