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Epsilon Draconis

Epsilon Draconis
Draco constellation map.png
Location of ε Draconis (upper left).
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension 19h 48m 10.3521s
Declination 70° 16′ 04.549″
Apparent magnitude (V) 3.9974
Characteristics
Spectral type G8III+F5III
U−B color index +0.48
B−V color index +0.88
Astrometry
Radial velocity (Rv) +3.1 km/s
Proper motion (μ) RA: +79.31 mas/yr
Dec.: 39.08 mas/yr
Parallax (π) 22.04 ± 0.37mas
Distance 148 ± 2 ly
(45.4 ± 0.8 pc)
Absolute magnitude (MV) 0.71
Details
Mass 2.7 M
Radius 10 R
Luminosity ~60 L
Temperature 5,068  K
Metallicity -0.31 Fe/H
Rotational velocity (v sin i) 1.2  km/s
Age 5.0×108 years
Other designations
Tyl, ε Dra, 63 Dra, HR 7582, AG+70° 689, BD+69° 1070, HD 188119, HIP 97433, PLX 4689, SAO 9540, GC 27471, CCDM J19482+7016AB, 2MASS J19481035+7016045, IRAS 19483+7008
Database references
SIMBAD data

Coordinates: Sky map19h 48m 10.35s, +70° 16′ 04.55″

Epsilon Draconis (ε Dra, ε Draconis) is a fourth-magnitude star in the constellation Draco. This star along with Delta Draconis (Altais), Pi Draconis and Rho Draconis forms an asterism known as Al Tāis, meaning "the Goat".

In Chinese astronomy, 天廚 (Tiān Chú), meaning the Celestial Kitchen, refers to an asterism consisting of Epsilon Draconis, Delta Draconis, Sigma Draconis, Rho Draconis, 64 Draconis and Pi Draconis. Consequently, Epsilon Draconis itself is known as 天廚三 (Tiān Chú sān, English: the Third Star of the Celestial Kitchen.) Most authors do not use a traditional name for this star, using the Bayer designation; however, in the literature it can be found the name Tyl.

With a declination in excess of 70 degrees north, Epsilon Draconis is principally visible in the northern hemisphere, with southern locations north of 20° South able to see it just above the horizon. The star is circumpolar throughout all of Europe, China, most of India and as far south as the tip of the Baja peninsula in North America as well as other locations around the globe having a latitude greater than ± 20° North. Since Epsilon Draconis has an apparent magnitude of almost 4.0, the star is easily observable to the naked eye as long as one's stargazing is not hampered by the light pollution common to most cities.


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Wikipedia

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