Xi Herculis

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Template:Short description

Xi Herculis
File:Xi Herculis.jpg
ξ Herculis in optical light
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hercules
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.70[2]
Characteristics
Evolutionary stage red clump[3]
Spectral type G8 III[4]
U−B Template:Engvar +0.66[2]
B−V Template:Engvar +0.93[2]
Astrometry
Radial velocity (Rv)Script error: No such module "val".[5] km/s
Proper motion (μ) RA: 81.919 mas/yr[1]
Dec.: Script error: No such module "val". mas/yr[1]
Parallax (π)23.8544±0.1068 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)+0.62[6]
Details
Mass2.01[7] Template:Solar mass
RadiusScript error: No such module "val".[8] Template:Solar radius
LuminosityScript error: No such module "val".[8] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[9] cgs
TemperatureScript error: No such module "val".[8] K
Metallicity [Fe/H]Script error: No such module "val".[9] dex
Rotation67[3] d
Rotational velocity (v sin i)2.8[5] km/s
Age2.48[7] Gyr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
ξ Her, 92 Her, BD+29°3156, HD 163993, HIP 87933, HR 6703, SAO 85590[10]
Database references
SIMBADdata

Script error: No such module "Check for unknown parameters".

Xi Herculis is a solitary[11] star located within the northern constellation of Hercules. The star is visible to the naked eye with an apparent visual magnitude of 3.70.[2] Based upon an annual parallax shift of 23.85 mas as seen from Earth, it is located 137 light years from the Sun.[1] At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.05 due to interstellar dust. It is a suspected member of the Sirius stream of co-moving stars.[12]

File:XiHerLightCurve.png
A light curve for Xi Herculis, plotted from Hipparcos data[13]

This is an evolved G-type giant star with a stellar classification of G8 III.[4] It is a red clump star, which means it is on the horizontal branch and generating energy through the thermonuclear fusion of hydrogen at its core. The star is emitting X-rays with a luminosity of Script error: No such module "val". in the 0.3–10 keV band.[3] It has twice[7] the mass of the Sun but, at the age of two and a half billion years,[7] it has expanded to 10 times the Sun's radius. The star is radiating 57 times the solar luminosity from its photosphere at an effective temperature of 5,032 K.[8]

Xi Herculis was discovered to be a variable star when the Hipparcos data was analyzed.[14] It is a semiregular variable star, oscillating in brightness by 3 hundredths of a magnitude, over a period of 120.8 days.[15]

Chinese name

In R.H.Allen's book Star Names: Their Lore and Meaning, this star, together with ν Her and 99 Her (b Herculis) represent the state of Zhongshan (or Chung Shan' "the Middle Mountain"),[16] but in Chinese literature, that names is applied to ο Her.[17]

Markov 1, the mini teapot

One third of a degree to the north-northwest of Xi Herculis is the location of a telescopic asterism in the shape of a teapot. This teapot (Markov 1) could be seen as a somewhat twisted small equivalent of the large and easy to recognize teapot asterism in the constellation Sagittarius.

References

<templatestyles src="Reflist/styles.css" />

  1. ↑ a b c d e Template:Cite DR3
  2. ↑ a b c d Script error: No such module "citation/CS1".
  3. ↑ a b c Script error: No such module "citation/CS1".
  4. ↑ a b Script error: No such module "citation/CS1".
  5. ↑ a b Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ a b c d Script error: No such module "citation/CS1".
  8. ↑ a b c d Script error: No such module "Citation/CS1".
  9. ↑ a b Script error: No such module "citation/CS1".
  10. ↑ Template:Cite simbad
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 6 日 Template:Webarchive

Script error: No such module "Check for unknown parameters".

Template:Stars of Hercules

Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=Xi_Herculis&oldid=5699143"