GQ Lupi

{{short description|Star in the constellation of Lupus}} {{Starbox begin}} {{Starbox image | image = [[Image:GQLupLightCurve.png|250px]] | caption = A [[Photometric_system#Photometric_letters|visual band]] [[light curve]] for GQ Lupi. The main plot (from [[All Sky Automated Survey|''ASAS'']] data<ref name=ASASServer/>), shows the long-term variability, and the inset plot (adapted from Broeg ''et al.''<ref name="Broeg2007"/>) shows the short-term periodic brightness variation. }} {{Starbox observe 2s | epoch = J2000.0 | constell = [[Lupus (constellation)|Lupus]]<ref name=vsx/> | component1 = GQ Lupi A | ra1 = {{RA|15|49|12.1054}}<ref name="Gaia DR3 for A"/> | dec1 = {{DEC|−35|39|05.058}}<ref name="Gaia DR3 for A"/> | appmag_v1 = {{Val|11.3|-|14.3}}<ref name=vsx/> | component2 = GQ Lupi C | ra2 = {{RA|15|49|13.3078}}<ref name="Gaia DR3 for C"/> | dec2 = {{DEC|−35|39|11.761}}<ref name="Gaia DR3 for C"/> | appmag_v2 = 19.72<ref name=msc/> }} {{Starbox character | component1 = GQ Lupi A | type = [[Pre-main sequence]]<ref name=ducourant2005/> | class = K7Ve<ref name=Herbig1977/> | b-v = 0.96<ref name=simbad /> | u-b = | variable = [[T Tauri variable]]<ref name=vsx/> | component2 = GQ Lupi C | type2 = [[Pre-main sequence]]<ref name="Alcala2020"/> | class2 = M4<ref name="Alcala2020"/> | b-v2 = | u-b2 = | variable2 = }} {{Starbox astrometry | component1 = GQ Lupi A | radial_v = {{Val|-3.6|1.3}}<ref name=Frasca2017/> | prop_mo_ra = {{val|−14.133}}<ref name="Gaia DR3 for A"/> | prop_mo_dec = {{val|−23.329}}<ref name="Gaia DR3 for A"/> | parallax = 6.4893 | p_error = 0.0289 | parallax_footnote = <ref name="Gaia DR3 for A"/> | component2 = GQ Lupi C | prop_mo_ra2 = {{val|−14.508}}<ref name="Gaia DR3 for C"/> | prop_mo_dec2 = {{val|−23.862}}<ref name="Gaia DR3 for C"/> | parallax2 = 5.7229 | p_error2 = 0.3559 | parallax_footnote2 = <ref name="Gaia DR3 for C"/> }} {{Starbox relpos | primary = GQ Lupi A | component = GQ Lupi C | projsep = 2430<ref name="Alcala2020"/> }} {{Starbox detail | component1 = GQ Lupi A | mass = {{Val|1.03|0.05}}<ref name=MacGregor2017/> | radius = {{Val|1.75|0.06|0.07}}<ref name=Kammerer2025/> | luminosity = {{val|1.05|0.27|0.22}}<ref name=Xuan2024/> | gravity = 3.7<ref name=Donati2012/> | temperature = {{Val|4306|35}}<ref name=Kammerer2025/> | rotation = {{Val|8.45|0.20}}<ref name=Broeg2007/> days | rotational_velocity = {{Val|5.66|0.02}}<ref name=Gonzalez2025/> | age_myr = {{Val|2.8|1.8|1.1}}<ref name=Xuan2024/> | component2 = GQ Lupi C | metal2 = | mass2 = {{Val|0.15|0.05}}<ref name="Alcala2020"/> | radius2 = {{Val|0.87|0.20}}<ref name="Alcala2020"/> | rotational_velocity2 = {{Val|13|6}}<ref name="Alcala2020"/> | luminosity2 = {{Val|0.07|0.02}}<ref name="Alcala2020"/> | temperature2 = {{Val|3230|101}}<ref name="Alcala2020"/> }} {{Starbox catalog | names = {{odlist|V=GQ Lup|WDS=J15492-3539}}<ref name=simbadA/> | component1 = GQ Lupi A | names1 = [[Durchmusterung|CD]]−35°10525<ref name=simbadA/> | component2 = GQ Lupi C | names2 = {{odlist|2MASS=J15491331-3539118}}<ref name=simbadC/> }} {{Starbox reference | Simbad = V*+GQ+Lup |sn=GQ Lupi A }} {{Starbox reference|no_heading=y | Simbad = TIC+442623949 |sn=GQ Lupi C }} {{Starbox end}}

'''GQ Lupi''' is a possible [[binary star]] system in the constellation [[Lupus (constellation)|Lupus]]. The system is young, with an age of a few million years (for comparison, the [[Solar System]] is roughly 4.6 billion years old), and is within the Lupus I [[star-forming region]],<ref name="Alcala2020"/> which is part of the [[Scorpius–Centaurus association]].<ref name=Comeron2008/>

==Stellar system== The primary component is designated GQ Lupi A, and was referred to simply as GQ Lupi before the discovery of the secondary stellar companion. It is a [[T Tauri star]], with a variable [[apparent magnitude]] ranging from 11.3 at brightest and 14.3 at faintest.<ref name=vsx/> The [[spectral type]] is K7Ve, with the 'e' indicating [[emission lines]] in the spectrum,<ref name=Herbig1977/> which in classical T Tauri stars such as GQ Lupi results from an extensive surrounding disk.<ref name=vsx/> The star has 1.03 times the [[mass of the Sun]]<ref name=MacGregor2017/> and 1.75 times the [[Sun's radius]], with an [[effective temperature]] of {{val|4306|ul=K}}.<ref name=MacGregor2017/> Its age is estimated at {{Val|2.8|1.8|1.1}} million years.<ref name=Xuan2024/> This star is surrounded by a [[circumstellar disk]] with a major axis of {{Val|59|12|ul=AU}}.<ref name=MacGregor2017/>

In 2020, a low-mass companion of GQ Lupi was discovered at a separation of about 16 [[arcsecond]]s, or {{val|2400|u=AU}}. Designated 2MASS J15491331-3539118 in the [[2MASS]] catalogue, it is a young stellar object that is likely gravitationally bound to the primary star, although the low quality of the companion's [[proper motion]] and [[parallax]] does not allow for a definitive conclusion. It is estimated to be approximately 15% the Sun's mass and 87% the Sun's radius. It has an effective temperature of about {{val|3230|u=K}}, indicating that it is a [[red dwarf]] with the spectral type M4.<ref name="Alcala2020">{{cite journal|title=2MASS J15491331-3539118: a new low-mass wide companion of the GQ Lup system|first=J. M.|last=Alcalá|journal=Astronomy & Astrophysics|display-authors=etal|arxiv=2001.10879|year=2020|volume=635|pages=L1|doi=10.1051/0004-6361/201937309|bibcode=2020A&A...635L...1A |s2cid=210942917}}</ref>

==Substellar companion== [[File:The Sub-Stellar Companion to GQ Lupi.jpg|thumb|left|VLT NACO image, taken in the Ks-band, of GQ Lupi. The feeble point of light to the right of the star is the newly found cold companion. It is 250 times fainter than the star itself and it located 0.73 [[arc second]] west. At the distance of GQ Lupi, this corresponds to a separation of roughly 100 [[astronomical unit|AU]]. North is up and East is to the left.]]In 2005, Ralph Neuhäuser and his colleagues reported a [[substellar object]], [[GQ Lupi b]], orbiting the star. Along with [[2M1207b]], this was one of the first [[extrasolar planet]] candidates to be directly imaged. The image was made with the [[Very Large Telescope|VLT telescope]] at [[Paranal Observatory]], [[Chile]], on June 25, 2004. Depending on its mass and the [[definition of a planet]], GQ Lupi b may or may not be considered a planet.<ref name=eso>[http://www.eso.org/public/outreach/press-rel/pr-2005/pr-09-05.html Is this a Brown Dwarf or an Exoplanet? New Young Sub-stellar Companion Imaged with the VLT] {{webarchive|url=https://web.archive.org/web/20080507074340/http://www.eso.org/public/outreach/press-rel/pr-2005/pr-09-05.html |date=2008-05-07 }}, ESO Press Release 09/05, April 7, 2005. Accessed on line June 13, 2008.</ref> As of 2006, the [[International Astronomical Union]] Working Group on Extrasolar Planets described GQ Lupi b as a "possible planetary-mass companion to a young star".<ref>[http://www.dtm.ciw.edu/boss/planets.html Lists of Extrasolar Planets] {{webarchive|url=https://web.archive.org/web/20131029204807/http://www.dtm.ciw.edu/boss/planets.html |date=2013-10-29 }}, IAU Working Group on Extrasolar Planets, August 28, 2006. Accessed on line June 13, 2008.</ref>

{{OrbitboxPlanet begin |period_unit=year}} {{OrbitboxPlanet | exoplanet = [[GQ Lupi b|b]] | mass = ~10{{snd}}40<ref name="Gonzalez2025"/> | radius = {{val|3.7|0.7}}<ref name=Xuan2024/> | semimajor = {{val|97.7|8.9|7.1}}<ref name=Venkatesan2025/> | period = {{Val|921|159|124}}{{efn|name=period|1=Calculated using {{nowrap|1=P2 = <var>a</var>3 / <var>M</var>tot}}, where <var>a</var> is the [[semi-major axis]] in [[astronomical unit]]s, <var>M</var>tot is the total mass of the system, in {{solar mass}}, and P is the period in years. Upper error bar calculated with the {{val|-7.14}} uncertainty in <var>a</var> and {{val|+0.07}} in <var>M</var>tot. Lower error bar calculated with the {{val|+8.92}} uncertainty in <var>a</var> and {{val|-0.06}} in <var>M</var>tot.}} | eccentricity = {{val|0.35|0.10|0.09}}<ref name=Venkatesan2025/> | inclination = {{val|48|4|5}}<ref name=Venkatesan2025/> }} {{Orbitbox end}}

==Notes== {{Notelist}}

==References== {{Reflist|refs=

<ref name=simbad>{{cite simbad|title=V* GQ Lup|accessdate=June 13, 2008}}</ref>

<ref name=ASASServer>{{cite web |title=ASAS All Star Catalogue |url=https://www.astrouw.edu.pl/asas/?page=aasc |publisher=The All Sky Automated Survey |access-date=8 December 2021}}</ref>

<ref name=simbadA>{{Cite SIMBAD|title=GQ Lup}}</ref>

<ref name=simbadC>{{Cite SIMBAD|title=V* GQ Lup C}}</ref>

<ref name=Herbig1977>{{Cite journal |last=Herbig |first=G. H. |date=June 1977 |title=Radial velocities and spectral types of T Tauri stars. |bibcode=1977ApJ...214..747H |journal=The Astrophysical Journal |language=en |volume=214 |pages=747–758 |doi=10.1086/155304 |issn=0004-637X}}</ref>

<ref name=Kammerer2025>{{cite journal |last1=Kammerer |first1=J. |last2=Winterhalder |first2=T. O. |last3=Lacour |first3=S. |last4=Stolker |first4=T. |last5=Marleau |first5=G.-D. |last6=Balmer |first6=W. O. |last7=Moore |first7=A. F. |last8=Piscarreta |first8=L. |last9=Toci |first9=C. |date=2025-11-02 |title=The ExoGRAVITY survey: A K-band spectral library of giant exoplanet and brown dwarf companions |journal=[[The Astrophysical Journal]] |volume=704 |pages=A318 |arxiv=2510.08691 |doi=10.1051/0004-6361/202556860 |bibcode=2025A&A...704A.318K }}</ref>

<ref name=Frasca2017>{{Cite journal |last1=Frasca |first1=A. |last2=Biazzo |first2=K. |last3=Alcalá |first3=J. M. |last4=Manara |first4=C. F. |last5=Stelzer |first5=B. |last6=Covino |first6=E. |last7=Antoniucci |first7=S. |date=2017-06-01 |title=X-shooter spectroscopy of young stellar objects in Lupus - Atmospheric parameters, membership, and activity diagnostics |journal=Astronomy & Astrophysics |language=en |volume=602 |pages=A33 |doi=10.1051/0004-6361/201630108 |arxiv=1703.01251 |bibcode=2017A&A...602A..33F |issn=0004-6361}}</ref>

<ref name=vsx>{{Cite web |title=VSX : Detail for GQ Lup |url=https://vsx.aavso.org/index.php?view=detail.top&oid=17792 |access-date=2026-02-07 |website=vsx.aavso.org}}</ref>

<ref name=Venkatesan2025>{{Cite journal |last1=Venkatesan |first1=Vidya |last2=Blunt |first2=S. |last3=Wang |first3=J. J. |last4=Lacour |first4=S. |last5=Marleau |first5=G.-D. |last6=Coleman |first6=G. A. L. |last7=Guerrero |first7=L. |last8=Balmer |first8=W. O. |last9=Pueyo |first9=L. |last10=Stolker |first10=T. |last11=Kammerer |first11=J. |last12=Pourré |first12=N. |last13=Nowak |first13=M. |last14=Rickman |first14=E. |last15=Sivaramakrishnan |first15=A. |date=2025-10-24 |title=Constraints on the Orbit of the Young Substellar Companion GQ Lup B from High-resolution Spectroscopy and VLTI/GRAVITY Astrometry |journal=The Astrophysical Journal |volume=993 |issue=1 |pages=69 |doi=10.3847/1538-4357/ae0c15 |doi-access=free |arxiv=2509.20621 |bibcode=2025ApJ...993...69V |issn=0004-637X}}</ref>

<ref name=Xuan2024>{{Cite journal |last1=Xuan |first1=Jerry W. |last2=Hsu |first2=Chih-Chun |last3=Finnerty |first3=Luke |last4=Wang |first4=Jason |last5=Ruffio |first5=Jean-Baptiste |last6=Zhang |first6=Yapeng |last7=Knutson |first7=Heather A. |last8=Mawet |first8=Dimitri |last9=Mamajek |first9=Eric E. |last10=Inglis |first10=Julie |last11=Wallack |first11=Nicole L. |last12=Bryan |first12=Marta L. |last13=Blake |first13=Geoffrey A. |last14=Mollière |first14=Paul |last15=Hejazi |first15=Neda |date=2024-07-01 |title=Are These Planets or Brown Dwarfs? Broadly Solar Compositions from High-resolution Atmospheric Retrievals of ∼10–30 MJup Companions |journal=The Astrophysical Journal |volume=970 |issue=1 |pages=71 |doi=10.3847/1538-4357/ad4796 |doi-access=free |arxiv=2405.13128 |bibcode=2024ApJ...970...71X |issn=0004-637X}}</ref>

<ref name=Broeg2007>{{Cite journal |last1=Broeg |first1=C. |last2=Schmidt |first2=T. O. B. |last3=Guenther |first3=E. |last4=Gaedke |first4=A. |last5=Bedalov |first5=A. |last6=Neuhäuser |first6=R. |last7=Walter |first7=F. M. |date=June 2007 |title=Rotational period of GQ Lupi |bibcode=2007A&A...468.1039B |journal=Astronomy and Astrophysics |language=en |volume=468 |issue=3 |pages=1039–1044 |doi=10.1051/0004-6361:20066793 |issn=0004-6361}}</ref>

<ref name=Donati2012>{{Cite journal |last1=Donati |first1=J.-F. |last2=Gregory |first2=S. G. |last3=Alencar |first3=S. H. P. |last4=Hussain |first4=G. |last5=Bouvier |first5=J. |last6=Dougados |first6=C. |last7=Jardine |first7=M. M. |last8=Ménard |first8=F. |last9=Romanova |first9=M. M. |date=2012-09-05 |title=Magnetometry of the classical T Tauri star GQ Lup: non-stationary dynamos and spin evolution of young Suns |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=425 |issue=4 |pages=2948–2963 |doi=10.1111/j.1365-2966.2012.21482.x |doi-access=free |arxiv=1206.1770 |bibcode=2012MNRAS.425.2948D |issn=0035-8711 }}</ref>

<ref name=MacGregor2017>{{Cite journal |last1=MacGregor |first1=Meredith A. |last2=Wilner |first2=David J. |last3=Czekala |first3=Ian |last4=Andrews |first4=Sean M. |last5=Dai |first5=Y. Sophia |last6=Herczeg |first6=Gregory J. |last7=Kratter |first7=Kaitlin M.|author7-link=Kaitlin Kratter |last8=Kraus |first8=Adam L. |last9=Ricci |first9=Luca |last10=Testi |first10=Leonardo |date=2017-01-16 |title=ALMA Measurements of Circumstellar Material in the GQ Lup System |journal=The Astrophysical Journal |volume=835 |issue=1 |pages=17 |doi=10.3847/1538-4357/835/1/17 |doi-access=free |arxiv=1611.06229 |bibcode=2017ApJ...835...17M |issn=0004-637X}}</ref>

<ref name=Comeron2008>{{Cite journal |last=Comerón |first=F. |year=2008 |title=The Lupus Clouds |bibcode=2008hsf2.book..295C |journal=Handbook of Star Forming Regions, Volume II |language=en |volume=5 |pages=295}}</ref>

<ref name=ducourant2005>{{cite journal |last1=Ducourant |first1=C. |last2=Teixeira |first2=R. |last3=Périé |first3=J. P. |last4=Lecampion |first4=J. F. |last5=Guibert |first5=J. |last6=Sartori |first6=M. J. |title=Pre-main sequence star Proper Motion Catalogue |journal=Astronomy and Astrophysics |date=2005 |volume=438 |issue=2 |page=769 |doi=10.1051/0004-6361:20052788 |bibcode=2005A&A...438..769D }}</ref>

<ref name=msc>{{cite journal |bibcode=2018ApJS..235....6T |title=The Updated Multiple Star Catalog |last1=Tokovinin |first1=Andrei |journal=The Astrophysical Journal Supplement Series |date=2018 |volume=235 |issue=1 |page=6 |doi=10.3847/1538-4365/aaa1a5 |doi-access=free |arxiv=1712.04750 }}</ref>

<ref name="Gonzalez2025">{{Cite journal |last=González Picos |first=D. |last2=Snellen |first2=I. A. G. |last3=de Regt |first3=S. |last4=Landman |first4=R. |last5=Zhang |first5=Y. |last6=Gandhi |first6=S. |last7=Sánchez-López |first7=A. |date=January 2025 |title=The ESO SupJup Survey: IV. Unveiling the carbon isotope ratio of GQ Lup B and its host star |url=https://www.aanda.org/10.1051/0004-6361/202451936 |journal=Astronomy & Astrophysics |volume=693 |pages=A298 |arxiv=2501.01789 |bibcode=2025A&A...693A.298G |doi=10.1051/0004-6361/202451936 |issn=0004-6361}}</ref>

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==External links== * {{cite journal |last1=Guenther |first1=E. W. |last2=Neuhäuser |first2=R. |last3=Wuchterl |first3=G. |last4=Mugrauer |first4=M. |last5=Bedalov |first5=A. |last6=Hauschildt |first6=P. H. |title=The low-mass companion of GQ Lup |journal=Astronomische Nachrichten |date=2005 |volume=326 |issue=10 |pages=958–963 |doi=10.1002/asna.200510461 |arxiv=astro-ph/0510794 |bibcode=2005AN....326..958G}} * {{cite arXiv |last1=Neuhaeuser |first1=Ralph |title=Homogeneous comparison of directly detected planet candidates: GQ Lup, 2M1207, AB Pic |date=2005 |eprint=astro-ph/0509906 }} *{{cite web |url=https://www.newscientist.com/article.ns?id=dn7225 |title=First image of exoplanet orbiting Sun-like star |accessdate=2008-06-09 |work=New Scientist |date=2005-04-04 |first=Kelly |last=Young}} *{{cite web |url=http://news.bbc.co.uk/1/hi/wales/4408187.stm |title=Telescopes see 'distant planet' |accessdate=2008-06-09 |work=BBC News |date=2005-04-04}} *{{cite web |url=https://www.space.com/scienceastronomy/050430_exoplanet_image.html |title=Fresh Debate over First Photo of Extrasolar Planet |accessdate=2008-06-09 |work=SPACE.com |date=2005-04-30 |first=Robert Roy |last=Britt}} {{-}}

[[Category:Planetary systems with one confirmed planet]] [[Category:Lupus (constellation)]] [[Category:T Tauri stars]] [[Category:K-type main-sequence stars]] [[Category:Objects with variable star designations|Lupi, GQ]] [[Category:Durchmusterung objects]]