Gliese 570

{{Short description|Quaternary star system in the constellation Libra}} {{Sky|14|57|28.00144|-|21|24|55.7131|19.199}} {{Starbox begin}} {{Starbox image | image=[[File:Gl570satlas.jpg|250px]]|caption=The quaternary [[star system]] Gliese 570. The T-type methane [[brown dwarf]] Gliese 570D is indicated with an arrow. '''Credit''': ''[[2MASS]]'' }} {{Starbox observe | epoch = J2000.0 | constell = [[Libra (constellation)|Libra]] | ra = {{RA|14|57|28.00144}}<ref name=aaa474_2_653/> | dec = {{DEC|-21|24|55.7131}}<ref name=aaa474_2_653/> | appmag_v = 5.75 / 8.07 / 10.5{{cn|date=February 2026}} }} {{Starbox character | class = K4V / M1V / M3V / T7V{{cn|date=February 2026}} | b-v = 1.11 / 1.51 | u-b = 1.06 /1.22 | variable = None / [[BY Draconis variable|BY Dra]]{{cn|date=February 2026}} }} {{Starbox astrometry | component1 = A | radial_v = {{val|+26.75|0.12}}<ref name=dr3a/> | prop_mo_ra = +1031.472 | prop_mo_dec = {{val|-1723.619|fmt=none}} | pm_footnote = <ref name=dr3a/> | parallax = 169.8843 | p_error = 0.0653 | parallax_footnote=<ref name=dr3a/> | absmag_v = 6.89<ref name=Holmberg2009/> }} {{Starbox astrometry|no_heading=y | component1 = BC | radial_v = +25.9<ref name=rvbc/> | prop_mo_ra = +961.78<ref name=aaa474_2_653/> | prop_mo_dec = {{val|-1677.83|fmt=none}}<ref name=aaa474_2_653/> | parallax = 169.1 | p_error = 0.9 | parallax_footnote=<ref name=Merle2023/> | absmag_v = 9.19<ref name=Holmberg2009/> / 11.05{{cn|date=February 2026}} }} {{Starbox astrometry|no_heading=y | component1 = D | radial_v = | prop_mo_ra = +1038.08<ref name=weinberger2016/> | prop_mo_dec = {{val|-1677.59|fmt=none}}<ref name=weinberger2016/> | parallax = 169.30 | p_error = 1.70 | parallax_footnote=<ref name=faherty2012/> }} {{Starbox orbit | reference = <ref name=Merle2023/> | primary = B | name = C | period_unitless = {{val|308.86|0.01}} days | axis_unitless = {{val|148.1|0.5|ul=mas}} | eccentricity = {{val|0.758|0.001}} | inclination = {{val|106.1|0.1}} | node = {{val|16.9|0.2}} | periarg = {{val|308.3|0.2}} | periastron = {{val|50270.86|0.04}} | k1 = {{val|18.23|0.06}} | k2 = {{val|27.2|0.1}} }} {{Starbox detail | component1 = A | mass = {{nowrap|0.802 ± 0.040}}<ref name="aaa505"/> | radius = {{val|0.715|0.009}}<ref name=Rains2020/> | luminosity_bolometric = {{val|0.19|0.01}}<ref name=Rains2020/> | temperature = {{val|4505|76}}<ref name=Rains2020/> | rotational_velocity = 1.50<ref name="aaa505" /> | metal_fe = 0.06<ref name="aaa505" /> | age = }} {{Starbox detail|no_heading=y | component1 = B | mass = {{val|0.562|0.006}}<ref name=Merle2023/> | radius = {{solar radius calculator|type=logLT|-1.276|logLerr=0.05|3530|Terr=45|decimals=3}}<ref name=Hillenbrand2004/>{{efn|name=rad1}} | luminosity = {{val|0.053|0.006}}<ref name=Hillenbrand2004/> | temperature = {{val|3530|46|45}}<ref name=Hillenbrand2004/> | component2 = C | mass2 = {{val|0.377|0.003}}<ref name=Merle2023/> | radius2 = {{solar radius calculator|type=logLT|-1.768|logLerr=0.05|3304|Terr=64|decimals=3}}<ref name=Hillenbrand2004/>{{efn|name=rad2}} | luminosity2 = {{val|0.0171|0.0021|0.0019}}<ref name=Hillenbrand2004/> | temperature2 = {{val|3304|64|63}}<ref name=Hillenbrand2004/> }} {{Starbox detail|no_heading=y | component1 = D | mass_mj = {{val|34.6|7.5|6.5}}<ref name=Zhang2021/> | temperature = {{val|786|20}}<ref name=Zhang2021/> | luminosity = {{val|2.88|0.21|0.19|e=-7}}<ref name=Zhang2021/> | radius_rj = {{val|0.89|0.05|0.04}}<ref name=Zhang2021/> | gravity = {{val|5.04|0.13}}<ref name=Zhang2021/> }} {{Starbox catalog | names = {{odlist | Gould=33 G. Librae | ADS=9446 | GJ=570 | WDS=J14575-2125}}<ref name=Gould1879/> | component2 = A | names2 = {{odlist | V=KX Lib | BD=-20°4125 | FK5=1391 | HD=131977 | HIP=73184 | HR=5568 | LAL=27173 | LFT=1161 | LHS=387 | LPM=551 | LTT=5949 | PLX=3375 | SAO=183040}}, [[McCormick Observatory|MCC]] 726 | component3 = BC | names3 = {{odlist | BD=-20°4123 | HD=131976 | HIP=73182 | LFT=1160 | LHS=386 | LPM=550 | LTT=5948 | SAO=183039}} | component4 = D | names4 = {{odlist | 2MASS=J14571496-2121477}} }} {{Starbox reference | Simbad = TYC+6180-855-1|sn=A | Simbad2 = TYC+6180-1230-1|sn2=BC | Simbad3 = GJ+570+D|sn3=D | NSTED = GJ 570A | ARICNS = 01180 | EPE =  }} {{Starbox image | image= {{Location mark | image=Libra constellation map.svg | float=center | width=250 | position=right | mark=Red circle.svg | mark_width=7 | mark_link=Gliese 570 | x%=60.5 | y%=66.0 }} | caption=Location of Gliese 570 (circled) }} {{Starbox end}}

'''Gliese 570''' (or '''33 G. Librae''') is a quaternary [[star system]] approximately 19 [[light-year]]s away. The primary star is an [[orange dwarf]] [[star]] (much dimmer and smaller than the [[Sun]]). The other secondary stars are themselves a [[binary star|binary system]], two [[red dwarf]]s 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 (constellation)|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-year]]s 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== [[Image:GJ570D.jpg|thumb|250px|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 unit]]s from the binary components B and C, moving in an [[Orbital eccentricity|eccentric]] orbit that takes at least 2130 years to complete.<ref>{{cite web |url=http://ad.usno.navy.mil/wds/orb6.html |title=Sixth Catalog of Orbits of Visual Binary Stars |access-date=2008-05-18 |archive-url=https://web.archive.org/web/20090412084731/http://ad.usno.navy.mil/wds/orb6.html |archive-date=2009-04-12 |url-status=dead }}</ref> Gliese 570 A is [[spectral type]] K4V and emits X-rays.<ref name=Schmitt>{{ cite journal |author1=Schmitt JHMM |author2=Fleming TA |author3=Giampapa MS |title=The X-Ray View of the Low-Mass Stars in the Solar Neighborhood |journal=Astrophys. J. |date=September 1995 |volume=450 |issue=9 |pages=392–400 |bibcode=1995ApJ...450..392S |doi=10.1086/176149 |doi-access=free }}</ref> [[Radial velocity|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.<ref name="Howard2016"/>

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.<ref name=Schmitt/>

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.<ref>{{cite journal | bibcode=2000ApJ...531L..57B |author=Burgasser |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 | date=2000|doi=10.1086/312522 | last2=Kirkpatrick | first2=J. Davy | last3=Cutri | first3=Roc M. | last4=McCallon | first4=Howard | last5=Kopan | first5=Gene | last6=Gizis | first6=John E. | last7=Liebert | first7=James | last8=Reid | first8=I. Neill | last9=Brown | first9=Michael E.|pmid=10673414 | display-authors = 8|arxiv = astro-ph/0001194 |s2cid=19109066 }}</ref> 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|"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.<ref>{{cite journal | url=http://aa.springer.de/papers/0362002/2300585/small.htm | author=Kurster | display-authors=etal | 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 | date=2000 | pages=585–594 | bibcode=2000A&A...362..585E | access-date=2007-08-19 | archive-date=2012-02-08 | archive-url=https://web.archive.org/web/20120208035403/http://aa.springer.de/papers/0362002/2300585/small.htm | url-status=dead }}</ref> No extrasolar planets have been confirmed to exist in this multiple star system thus far.

==See also== * [[Epsilon Indi]] * [[Gliese 229]] * [[HD 188753]] * [[Iota Horologii]] * [[Phi2 Pavonis|Phi<sup>2</sup> Pavonis]] * [[List of nearest stars by spectral type#List of nearest K-type stars|List of nearest K-type stars]]

==Notes== {{Notelist|notes=

{{Efn|name=rad1|1=Calculated, using the [[Stefan-Boltzmann law]] and the star's [[effective temperature]] and luminosity, with respect to the [[Sun|solar]] nominal effective temperature of {{val|5772|ul=K}}:<math display="block">\sqrt{\biggl(\frac{5772}{3530}\biggr)^4 \cdot 10^{-1.276}} = 0.615\ R_\odot.</math>}}

{{Efn|name=rad2|1=Calculated, using the [[Stefan-Boltzmann law]] and the star's [[effective temperature]] and luminosity, with respect to the [[Sun|solar]] nominal effective temperature of {{val|5772|ul=K}}:<math display="block">\sqrt{\biggl(\frac{5772}{3304}\biggr)^4 \cdot 10^{-1.768}} = 0.399\ R_\odot.</math>}}

}}

==References== <references> <ref name=dr3a>{{Cite Gaia DR3|6232511606838403968}}</ref>

<ref name=Hillenbrand2004>{{Cite journal |last1=Hillenbrand |first1=Lynne A. |last2=White |first2=Russel J. |date=2004-04-01 |title=An Assessment of Dynamical Mass Constraints on Pre-Main-Sequence Evolutionary Tracks |journal=The Astrophysical Journal |language=en |volume=604 |issue=2 |pages=741 |doi=10.1086/382021 |arxiv=astro-ph/0312189 |bibcode=2004ApJ...604..741H |issn=0004-637X}}</ref>

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<ref name=Rains2020>{{cite journal | title=Precision angular diameters for 16 southern stars with VLTI/PIONIER | last1=Rains | first1=Adam D. | last2=Ireland | first2=Michael J. | last3=White | first3=Timothy R. | last4=Casagrande | first4=Luca | last5=Karovicova | first5=I. | journal=Monthly Notices of the Royal Astronomical Society | volume=493 | issue=2 | pages=2377–2394 | date=April 2020 | arxiv=2004.02343 | bibcode=2020MNRAS.493.2377R | doi=10.1093/mnras/staa282 | doi-access=free }}</ref>

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<ref name=weinberger2016>{{cite journal |bibcode=2016AJ....152...24W |title=Trigonometric Parallaxes and Proper Motions of 134 Southern Late M, L, and T Dwarfs from the Carnegie Astrometric Planet Search Program |journal=The Astronomical Journal |volume=152 |issue=1 |pages=24 |last1=Weinberger |first1=Alycia J. |last2=Boss |first2=Alan P. |last3=Keiser |first3=Sandra A. |last4=Anglada-Escudé |first4=Guillem |last5=Thompson |first5=Ian B. |last6=Burley |first6=Gregory |year=2016 |arxiv=1604.05611 |doi=10.3847/0004-6256/152/1/24 |s2cid=119287203 |doi-access=free }}</ref>

<ref name=faherty2012>{{cite journal |bibcode=2012ApJ...752...56F |title=The Brown Dwarf Kinematics Project (BDKP). III. Parallaxes for 70 Ultracool Dwarfs |journal=The Astrophysical Journal |volume=752 |issue=1 |pages=56 |last1=Faherty |first1=Jacqueline K. |last2=Burgasser |first2=Adam J. |last3=Walter |first3=Frederick M. |last4=Van Der Bliek |first4=Nicole |last5=Shara |first5=Michael M. |last6=Cruz |first6=Kelle L. |last7=West |first7=Andrew A. |last8=Vrba |first8=Frederick J. |last9=Anglada-Escudé |first9=Guillem |year=2012 |arxiv=1203.5543 |doi=10.1088/0004-637X/752/1/56 |s2cid=18160586 }}</ref>

<ref name=Holmberg2009>{{citation | display-authors=1 | last1=Holmberg | first1=J. | last2=Nordström | first2=B. | last3=Andersen | first3=J. | title=The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics | volume=501 | issue=3 |date=July 2009 | pages=941–947 | journal=Astronomy and Astrophysics | doi=10.1051/0004-6361/200811191 | bibcode=2009A&A...501..941H | arxiv=0811.3982 | s2cid=118577511 | postscript=. }}</ref>

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<ref name=Merle2023>{{Cite journal |last1=Merle |first1=T. |last2=Pourbaix |first2=D. |last3=Jorissen |first3=A. |last4=Siopis |first4=C. |last5=Eck |first5=S. Van |last6=Winckel |first6=H. Van |date=2024-04-01 |title=Update of SB9 orbits using HERMES/Mercator radial velocities |url=https://www.aanda.org/articles/aa/full_html/2024/04/aa45918-23/aa45918-23.html |journal=Astronomy & Astrophysics |language=en |volume=684 |pages=A74 |doi=10.1051/0004-6361/202345918 |doi-access=free |arxiv=2312.09151 |bibcode=2024A&A...684A..74M |issn=0004-6361}}</ref>

<ref name="Howard2016">{{cite journal |title=Limits on Planetary Companions from Doppler Surveys of Nearby Stars |last1=Howard |first1=Andrew W. |last2=Fulton |first2=Benjamin J. |journal=Publications of the Astronomical Society of the Pacific |volume=128 |issue=969 |at=114401 |year=2016 |arxiv=1606.03134 |bibcode=2016PASP..128k4401H |doi=10.1088/1538-3873/128/969/114401 |s2cid=118503912 }}</ref>

<ref name="aaa505">{{cite journal | title=Mass-radius relation of low and very low-mass stars revisited with the VLTI | journal=Astronomy and Astrophysics | volume=505 | issue=1 | date=October 2009 | pages=205–215 | doi=10.1051/0004-6361/200911976 | bibcode=2009A&A...505..205D |arxiv = 0906.0602 |last1=Demory |first1=Brice-Olivier |last2=Ségransan |first2=Damien |last3=Forveille |first3=Thierry |last4=Queloz |first4=Didier |last5=Beuzit |first5=Jean-Luc |last6=Delfosse |first6=Xavier |last7=Di Folco |first7=Emmanuel |last8=Kervella |first8=Pierre |last9=Le Bouquin |first9=Jean-Baptiste |last10=Perrier |first10=Christian |last11=Benisty |first11=Myriam |last12=Duvert |first12=Gilles |last13=Hofmann |first13=Karl-Heinz |last14=Lopez |first14=Bruno |last15=Petrov |first15=Romain |s2cid=14786643 }}</ref>

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==External links== * {{cite web |url=http://www.solstation.com/stars/gl570abc.htm |title=Gliese 570 / HR 5568 ABC |access-date=2008-06-12 |work=SolStation |archive-date=2011-05-13 |archive-url=https://web.archive.org/web/20110513234202/http://www.solstation.com/stars/gl570abc.htm |url-status=dead }} * {{cite web |url=http://www.space.com/scienceastronomy/astronomy/brown_dwarf_000117.html |title=Astronomers Unveil Hot Photo of Cool Star |access-date=2008-06-12 |last=Bridges |first=Andrew |date=2000-01-17 |work=SPACE.com |archive-date=2008-09-05 |archive-url=https://web.archive.org/web/20080905073938/http://www.space.com/scienceastronomy/astronomy/brown_dwarf_000117.html |url-status=dead }}

{{Nearest systems|3}} {{Stars of Libra}}

[[Category:Libra (constellation)]]  [[Category:K-type main-sequence stars]] [[Category:M-type main-sequence stars]] [[Category:T-type brown dwarfs]] [[Category:Triple star systems]]  [[Category:Gould objects|Librae, 33]] [[Category:Gliese and GJ objects|0570]] [[Category:Henry Draper Catalogue objects|131976]] [[Category:Bright Star Catalogue objects|5568]] [[Category:Hipparcos objects|073182 4]] [[Category:Durchmusterung objects|BD-20 4125]] [[Category:Hypothetical planetary systems]] [[Category:Population I stars]] [[Category:Objects with variable star designations|Librae, KX]]