Gliese 570

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Template:Short description Template:Sky

Gliese 570
Template:Location mark
Location of Gliese 570 (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Libra
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 5.75 / 8.07 / 10.5
Characteristics
Spectral type K4V / M1V / M3V / T7V
U−B Template:Engvar 1.06 /1.22
B−V Template:Engvar 1.11 / 1.51
Variable type None / BY Dra
Astrometry
A
Radial velocity (Rv)Script error: No such module "val".[2] km/s
Proper motion (μ) RA: +1031.472 mas/yr[2]
Dec.: Script error: No such module "val". mas/yr[2]
Parallax (π)169.8843±0.0653 mas[2]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)6.89[3]
BC
Radial velocity (Rv)+25.9[4] km/s
Proper motion (μ) RA: +961.78[1] mas/yr
Dec.: Script error: No such module "val".[1] mas/yr
Parallax (π)169.1±0.9 mas[5]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)9.19[3] / 11.05
D
Proper motion (μ) RA: +1038.08[6] mas/yr
Dec.: Script error: No such module "val".[6] mas/yr
Parallax (π)169.30±1.70 mas[7]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Orbit[5]
PrimaryB
CompanionC
Period (P)Script error: No such module "val". days
Semi-major axis (a)Script error: No such module "val".
Eccentricity (e)Script error: No such module "val".
Inclination (i)Script error: No such module "val".°
Longitude of the node (Ω)Script error: No such module "val".°
Periastron epoch (T)Script error: No such module "val".
Argument of periastron (ω)
(secondary)		Script error: No such module "val".°
Semi-amplitude (K1)
(primary)		Script error: No such module "val". km/s
Semi-amplitude (K2)
(secondary)		Script error: No such module "val". km/s
Details
A
Mass0.802 ± 0.040[8] Template:Solar mass
RadiusScript error: No such module "val".[9] Template:Solar radius
Luminosity (bolometric)Script error: No such module "val".[9] Template:Solar luminosity
TemperatureScript error: No such module "val".[9] K
Metallicity[FeH] = 0.06[8]
Rotational velocity (v sin i)1.50[8] km/s
Metallicity [Fe/H]{{{metal_fe2}}} dex
B
MassScript error: No such module "val".[5] Template:Solar mass
RadiusTemplate:Solar radius calculator[10]Template:Efn Template:Solar radius
LuminosityScript error: No such module "val".[10] Template:Solar luminosity
TemperatureScript error: No such module "val".[10] K
C
MassScript error: No such module "val".[5] Template:Solar mass
RadiusTemplate:Solar radius calculator[10]Template:Efn Template:Solar radius
LuminosityScript error: No such module "val".[10] Template:Solar luminosity
TemperatureScript error: No such module "val".[10] K
Metallicity [Fe/H]{{{metal_fe2}}} dex
D
MassScript error: No such module "val".[11] MJup
RadiusScript error: No such module "val".[11] RJup
LuminosityScript error: No such module "val".[11] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[11] cgs
TemperatureScript error: No such module "val".[11] K
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[12]
A: Template:Odlist, MCC 726
BC: Template:Odlist
D: Template:Odlist
Database references
SIMBADA
BC
D
Exoplanet Archivedata
ARICNSdata

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Gliese 570 (or 33 G. Librae) is a quaternary star system approximately 19 light-years away. The primary star is an orange dwarf star (much dimmer and smaller than the Sun). The other secondary stars are themselves a binary system, two red dwarfs that orbit the primary star. A brown dwarf has been confirmed to be orbiting in the system.

Distance and visibility

In the night sky, the Gliese 570 system lies in the southwestern part of Libra. The system is southwest of Alpha Librae and northwest of Sigma Librae. In the early 1990s, the European Hipparcos mission measured the parallax of components B and C, suggesting that the system was at a distance of 24.4 light-years from the Sun. This, however, was a relatively large error as Earth-based parallax and orbit observations suggest that the two stars are actually part of a system with Gliese 570 A, and must actually lie at the same distance.

Star system

File:Gl570satlas.jpg
The quaternary star system Gliese 570. The T-type methane brown dwarf Gliese 570D is indicated with an arrow. Credit: 2MASS
File:GJ570D.jpg
An artist's impression of Gliese 570 D (with imagined satellite) showing the primary stars

The primary star of the system (component A) is an orange dwarf star that may just have over three fourths the mass of the Sun, about 77 percent of its radius, and only 15.6 percent of its visual luminosity. It has a separation of 190 astronomical units from the binary components B and C, moving in an eccentric orbit that takes at least 2130 years to complete.[13] Gliese 570 A is spectral type K4V and emits X-rays.[14] Radial velocities of the primary obtained in the course of an extrasolar planet search at Lick Observatory show a linear trend probably due to the orbital motion of the Gliese 570 BC system around the primary.[15]

A binary system in their own right, components B and C are both rather dim red dwarf stars that have less mass, radius, and luminosity than the Sun. Component B is spectral type M1V, component C is spectral type M3V, and both emit X-rays.[14]

On January 15, 2000, astronomers announced that they had found one of the coolest brown dwarfs then known. Catalogued as Gliese 570 D, it was observed at a wide separation of more than 1,500 astronomical unit from the triple star system.[16] It has an estimated mass of 50 times that of Jupiter.

The status of Gliese 570 D as a brown dwarf was confirmed by Doppler spectroscopy at the Cerro Tololo Interamerican Observatory in Chile. The surface temperature of this substellar object was found to be a relatively cool 500 degrees Celsius, making it cooler and less luminous than any other then-known brown dwarf (including the prototype "T" dwarf), and classifying the object as a T7-8V brown dwarf. No X-rays have been reported from this brown dwarf.

Search for planets

In 1998, an extrasolar planet was announced to orbit the primary star within the Gliese 570 system. The planet, identified as "Gliese 570 Ab", was considered doubtful and the claim was retracted in 2000.[17] No extrasolar planets have been confirmed to exist in this multiple star system thus far.

See also

Notes

Template:Notelist

References

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  11. ↑ a b c d e Script error: No such module "Citation/CS1".
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  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ a b Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "Citation/CS1".
  17. ↑ Script error: No such module "Citation/CS1".

External links

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Template:Nearest systems Template:Stars of Libra

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