Gliese 570

Starbox begin
name = Gliese 570 ABCDStarbox observe
epoch = J2000.0
constell = Libra
ra = RA|14|57|28.0
dec = DEC|-21|24|55
appmag_v = 5.64 / ? / 9.90 Starbox character
class = K4V / M1V / M3V / T7V
b-v = 1.11 / 1.51
u-b = 1.06 /1.22
variable = "None" Starbox astrometry
radial_v = +27.9
prop_mo_ra = 1034.18
prop_mo_dec = -1725.60
parallax = 169.85
p_error = 0.82
absmag_v = 6.79 / ? / 11.05 Starbox detail|
age = ?
metal = 102%
mass = 0.76 / 0.55 / 0.35 / 0.05
radius = 0.77 / 0.65
rotation = 48.3 days
luminosity = 0.16 / 0.02 / 0.003 / 3•10^-6
temperature = 4170 / 2700
age = Starbox catalog
names = HD 131977 / 131976/ ?, BD -20°4125, LHS 387, LTT 5949, GCTP 3375.00, SAO 183040, FK5 1391, LFT 1161, LPM 551, Vys 726, ADS 9446, HIP 73184 / 73182 / ? Starbox reference
Simbad = HD+131977
ARICNS =

Gliese 570, also known as HR 5568, is a trinary star system approximately 19 light-years away in the constellation of Libra (the Scale). The primary star is an orange dwarf star (much dimmer and smaller then the Sun). The other secondary stars are a binary system themselves, two red dwarfs that orbit around one another. A brown dwarf has been confirmed to be orbiting in the system. As of 1998, an extrasolar planet was thought to orbit the primary star, but it was retracted in 2000.

Distance and visibility

In the night sky, the Gliese 570 system lies in the southwestern part of Libra (the Scale). The system would be located southwest Alpha Librae and northwest of Sigma Librae. In the early 1990s, the European Hipparcos mission measured the parallax of Gliese 570 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

The primary star of the system (Gliese 570 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 luminosity. Gliese 570 A has a separation of 190 astronomical units from the binary stars Gliese 570 B and C, moving in an eccentric orbit that takes at least 2130 years to complete. [cite web |url=http://ad.usno.navy.mil/wds/orb6.html |title=Sixth Catalog of Orbits of Visual Binary Stars |accessdate=2008-05-18]

A binary system on their own right, Gliese 570 B and C are both rather dim red dwarf stars that have less mass, radius, and luminosity then the Sun.

On January 15 2000, astronomers announced that they had found one of the coolest brown dwarfs then known. Cataloged as Gliese 570 D (or rarely Gliese 570 d) was observed at a wide separation of more than 1,500 astronomical unit from the triple star system. [cite journal | url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2000ApJ...531L..57B&db_key=AST&high=3c1a46b25814712 |author=Burgasser et al.|title=Discovery of a Brown Dwarf Companion to Gliese 570ABC: A 2MASS T Dwarf Significantly Cooler than Gliese 229B |journal = The Astrophysical Journal | volume=531 | issue=1 | pages=L57–L60 | year=2000|doi=10.1086/312522] 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 at 500 degrees Celsius, Gliese 570 D is definitely cooler and less luminous than any other known brown dwarf (including the prototype ) and classifying the object as a T7-8V brown dwarf.

Possible planetary system

In 1998, an extrasolar planet was announced to orbit the primary star within the Gliese 570 system. The planet (named "Gliese 570 Ab") was soon considered to be doubtful and would later be retracted in 2000. [cite journal | url= http://aa.springer.de/papers/0362002/2300585/small.htm|author=Kurster et al.|title=The planet search program at the ESO Coud´e Echelle spectrometer I. Data modeling technique and radial velocity precision tests |journal = Astronomy and Astrophysics | volume=362 | year=2000 | pages=585–594 ] Currently, there are no gas giant or smaller planets have been detected in this triple star system thus far.

PlanetboxOrbit hypothetical
exoplanet = Ab
mass = 0.75
period = 400
semimajor = 1
eccentricity = 0

See also

* Gliese 229
* HD 188753
* Iota Horologii
* Phi² Pavonis

References

External links

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