Lacaille 8760

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

Template:Short description Template:Sky

Lacaille 8760
Script error: No such module "Location map".
Observation data
Epoch J2000      Equinox J2000
Constellation Microscopium
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 6.67[2]
Characteristics
Spectral type M0Ve[3][4]
U−B Template:Engvar +1.165[3]
B−V Template:Engvar +1.395[3]
Variable type Flare star
Astrometry
Radial velocity (Rv)Template:Val[1] km/s
Proper motion (μ) RA: Template:Val mas/yr[1]
Dec.: Template:Val mas/yr[1]
Parallax (π)251.9124±0.0352 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)8.69[2]
Details
Mass0.60[2] Template:Solar mass
Radius0.51[5] Template:Solar radius
Luminosity (bolometric)0.072[6] Template:Solar luminosity
Luminosity (visual, LV)0.029 Template:Solar luminosity
Surface gravity (log g)4.78[5] cgs
Temperature3,800[7] K
Metallicity [Fe/H]Template:Val[8] dex
Rotational velocity (v sin i)3.3[4] km/s
AgeTemplate:Val[9] Gyr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[3]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Script error: No such module "Location map".

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

Lacaille 8760 (AX Microscopii) is a red dwarf star in the constellation Microscopium. It is one of the nearest stars to the Sun at about 12.9 light-years' distance, and the brightest M-class main-sequence star in Earth's night sky, although it is generally too faint to be seen without a telescope. At an apparent magnitude of +6.7, it may only be visible to the unaided eye under exceptionally good viewing conditions, under dark skies.

This star was originally listed in a 1763 catalog that was published posthumously by the French Abbé Nicolas-Louis de Lacaille. He observed it in the southern sky while working from an observatory at the Cape of Good Hope.[10] Number 8760 was assigned to this star in the 1847 edition of Lacaille's catalogue of 9,766 stars by Francis Baily.[11]

In the past, Lacaille 8760 has been classified anywhere from spectral class K7 down to M2. In 1979, the Irish astronomer Patrick Byrne discovered that it is a flare star,[12] and it was given the variable star designation AX Microscopii, or AX Mic. As a flare star it is relatively quiescent.

File:AXMicLightCurve.png
An ultraviolet band light curve for a flare on AX Microscopii, adapted from Byrne (1981)[12]

Lacaille 8760 is one of the largest and brightest red dwarfs known, with about 60%[2] the mass and 51%[5] the radius of the Sun. It is about five[9] billion years old and is spinning at a projected rotational velocity of 3.3 km/s.[4] The star is radiating 7.2%[6] of the luminosity of the Sun from its photosphere at an effective temperature of 3,800 K.[7]

Despite efforts by astronomers, as of 2011 no planets had been detected in orbit around this star.[13]

Lacaille 8760 orbits around the galaxy with a relatively high ellipticity of 0.23.[14] Its closest approach to the Sun occurred about 20,000 years ago when it came within Template:Convert.[15] Due to its low mass (60% of the Sun), it has an expected lifespan of about 75 billion (7.5 × 1010) years,[16] seven times longer than the Sun's.

References

Template:Reflist

External links

Template:Nearest systems Template:Stars of Microscopium

  1. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named GaiaDR3
  2. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named RECONS
  3. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  4. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named aaa460_3_695
  5. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named apjss168_2_297
  6. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named apj801_2_143
  7. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named apj667_1_527
  8. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Lindgren2017
  9. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Boehle_et_al_2019
  10. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named st200307
  11. ↑ Francis Baily. A Catalogue of 9766 Stars (1847), Page 219
  12. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named mnras195_143
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Carson2011
  14. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named rmaa34_37
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aaa379_634
  16. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named apj1_251_639
Retrieved from "http://debianws.lexgopc.com/wiki143/index.php?title=Lacaille_8760&oldid=1756106"