{{short description|Substellar companion to the star GQ Lupi}} {{Infobox planet | name = GQ Lupi b/B | image = The Sub-Stellar Companion to GQ Lupi.jpg | caption = Direct imaging of GQ Lupi b and its host star, in a near-infrared wavelength. The companion 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. <!-- DISCOVERY -->| discovery_ref = <ref name=Neuhauser2005/><ref name=eso/> | discoverer = Neuhäuser et al. | discovery_site = ESO's [[Paranal Observatory]],<br />[[Chile]] | discovered = April 2005 | discovery_method = [[Direct imaging]] <!-- DESIGNATIONS --> <!-- ORBITAL -->| orbit_ref = <ref name=Venkatesan2025/> | apoastron = {{val|132}}{{efn|name=apoastron|calculated with ''a'' {{=}} 1+''e'', where ''a'' is the semi-major axis and ''e'' is the eccentricity}} au | periastron = {{val|63.5}}{{efn|name=periastron|calculated with ''a'' {{=}} 1&minus;''e'', where ''a'' is the semi-major axis and ''e'' is the eccentricity}} au | semimajor = {{val|97.7|8.9|7.1|ul=au}} | eccentricity = {{Val|0.35|0.10|0.09}} | period = {{Val|921|159|124}}{{efn|name=period|1=Calculated using {{nowrap|1=P<sup>2</sup> = <var>a</var><sup>3</sup> / <var>M</var><sub>tot</sub>}},<br/> where <var>a</var> is the [[semi-major axis]] in [[astronomical unit]]s, <var>M</var><sub>tot</sub> 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><sub>tot</sub>. Lower error bar calculated with the {{val|+8.92}} uncertainty in <var>a</var> and {{val|-0.06}} in <var>M</var><sub>tot</sub>.}} years | inclination = {{val|48|4|5|ul=deg}} | asc_node = {{val|257|8|5|u=deg}} | time_periastron = | arg_peri = {{val|176|10|24|u=deg}} | semi-amplitude = | apsis = astron | star = [[GQ Lupi]] A <!-- PHYS CHARS -->| mass = 30 (10{{snd}}40)<ref name=Stolker2021/><ref name=Venkatesan2025/> {{Jupiter mass|link=y}}<br />{{val|22|2|3}}<ref name=Demars2023/> {{Jupiter mass}}<br />{{val|33|10}}<ref name=Xuan2024/> {{Jupiter mass}}<br />~{{val|20|10}}<ref name="Sun2024"/> {{Jupiter mass}}<br />~10 – 40<ref name=Gonzalez2025/> {{Jupiter mass}}<br />{{Val|26.4|2.9|3.8}}<ref name=Kammerer2025/> {{Jupiter mass}} | mean_radius = {{Val|3.7|0.7}}<ref name=Xuan2024/> {{Jupiter radius|link=y}} | single_temperature = {{Val|2719|14}}<ref name=Cugno2024/> [[Kelvin|K]] | surface_grav = {{Val|3.83|0.17|0.18}}<ref name=Gonzalez2025/> [[cgs]] | spectral_type = M9 (M8{{snd}}M9)<ref name=Stolker2021/><ref name=Gonzalez2025/> <!-- ATMOSPHERE --> <!-- NOTES -->}} [[File:Exoplanet Comparison GQ Lupi b.png|thumb|Size comparison with Jupiter]] '''GQ Lupi b''', or '''GQ Lupi B''' is a [[substellar companion]] to the [[T Tauri star]] [[GQ Lupi]]. Classified as either an [[exoplanet]]<ref name=Swastik2021/><ref name=Venkatesan2025/> or a [[brown dwarf]],<ref name=Alcalá2020/><ref name=Majidi2020/><ref name=Horstman2024/><ref name=Cugno2024/> this object is still in the early stages of its formation, [[Accretion (astrophysics)|accreting]] gas from its circumplanetary disk. GQ Lupi b is orbiting at nearly 100&nbsp;[[astronomical unit]]s from the star, with an estimated orbital period around a millenium. The object was discovered by R. Neuhäuser ''et al.'', through [[direct imaging]] and announced in April 2005, less than a month before the full confirmation of [[2M1207b]] was announced. Along with [[2M1207b]], this was one of the first [[extrasolar planet]] candidates to be directly imaged.

==Discovery== GQ Lupi b was discovered in 2005 by a team led by R. Neuhäuser. By analysing data taken from the [[Very Large Telescope#NACO|NACO]] adaptive optics aboard the [[Very Large Telescope]], they discovered a faint companion to GQ Lupi A, and combining this with archival observations from the [[Subaru Telescope|Subaru]] and [[Hubble Space Telescope]]s, they were able to confirm that the companion [[proper motion companion|co-moves with the star]] and thus is gravitationally bound.<ref name=Neuhauser2005/> At the time, this was considered to be the first [[direct imaging]] discovery of a planetary-mass companion orbiting a star.<ref name=Seifahrt2007/> The image was made with the [[European Southern Observatory]]'s [[Very Large Telescope|VLT telescope]] at the [[Paranal Observatory]], [[Chile]] on June 25, 2004.<ref name=eso/> In 2006, the [[International Astronomical Union|IAU]]'s Working Group on Extrasolar Planets described GQ Lup b as a "possible planetary-mass companion to a young star".<ref name="IAU-list"/>

==Location== GQ Lupi b is within the Lupus I molecular cloud,<ref name=Alcalá2020/> a [[star-forming region]]<ref name=Majidi2023/> that is part of the [[Scorpius–Centaurus association]].<ref name=Comeron2008/> The cloud is located at a distance of roughly {{convert|140|±|50|pc|ly|abbr=off|lk=on|order=flip}}.<ref name=Neuhauser2005/> The GQ Lupi system is located at a distance of {{val|{{convert|153.82|pc|ly|disp=number}}|{{convert|0.67|pc|ly|disp=number}}|{{convert|0.82|pc|ly|disp=number}}|u=ly}} ({{Val|153.82|0.67|0.82|u=pc}}).<ref name=Bailer-Jones2021/> As seen from Earth, it is within the constellation of [[Lupus (constellation)|Lupus]].<ref name=vsx/>

==Orbit and surroundings== GQ Lupi b orbits at a [[semi-major axis]] of 98&nbsp;[[astronomical unit]]s from its host star, having a moderate [[orbital eccentricity]] of 0.35. This means that the farthest passage ([[apoastron]]) occurs at 132&nbsp;au{{Efn|name=apoastron}} while the closest passage ([[periastron]]) occurs at 64&nbsp;au.{{efn|name=periastron}} The orbital period is of roughly 920 years,{{Efn|name=period}} and the orbit's [[inclination]] relative to Earth is {{val|48|u=deg}}.<ref name=Venkatesan2025/>

===Host star=== {{main|GQ Lupi}} GQ Lupi is a [[T Tauri star]], with a variable [[apparent magnitude]] ranging from 11.3 at brightest and 14.3 at faintest.<ref name=vsx/> Its [[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 a surrounding, extensive disk.<ref name=vsx/> The star has {{Val|1.03|0.05}} times the [[mass of the Sun]],<ref name=MacGregor2017/> {{Val|1.75|0.06|0.07}} times the [[Sun's radius]], and an [[effective temperature]] of {{Val|4306|35|ul=K}}.<ref name=Kammerer2025/> Its estimated age is {{Val|2.8|1.8|1.1}}&nbsp;[[million years]], which is thought to be the same of GQ Lupi b.<ref name=Xuan2024/>

GQ Lupi also likely has a more widely-separated stellar companion, named 2MASS J15491331-3539118 or GQ Lupi C. This star has a [[projected separation]] of from 2400&nbsp;[[astronomical unit|au]] from the primary, has roughly 0.15 times the mass of the Sun, 0.9 times the Sun's radius, and an effective temperature of 3200&nbsp;K.<ref name=Alcalá2020/>

===Circumplanetary material=== Emission by hydrogen in the near-infrared ([[Paschen lines|Paschen-beta]]) was first detected in 2007 with the [[Very Large Telescope]] (VLT). This was interpreted as a sign of [[Accretion disk|accretion]] of material from a disk.<ref name=Seifahrt2007/> Additionally [[Hydrogen-alpha|H-alpha]] emission was detected with Hubble.<ref name=Zhou2014/>

As a very young object, GQ Lupi b is still embedded in its [[circumplanetary disk]], composed by gas and dust, and [[Accretion (astrophysics)|accretes]] gas from it.<ref name=Stolker2021/><ref name=Cugno2024/><ref name=Horstman2024/> The disk has a radius of {{Val|80|10|ul=Jupiter radius}} and is inclined at {{Val|85.6|0.5}}° relative to Earth.<ref name=Cugno2024/>{{rp|5}} There is evidence for a cavity within the disk, which has been suggested to be caused the accretion of dust by forming satellites. Thus, the disk of GQ Lupi b may be in its late stages where the formation of satellites is taking place and the inner parts were already cleared.<ref name=Stolker2021/> The accretion rate of GQ Lupi b is estimated at {{Val|3.2|e=-7|u=Jupiter mass}} per year.<ref name=Stolker2021/>{{rp|1}}

==Physical parameters== As a young object that is still contracting, GQ Lupi b still retain a fairly large radius and a hot temperature when compared to older objects.<ref name=Patience2012/>{{rp|10}} Cold substellar objects are predicted to have radii below {{jupiter radius|1.2}},<ref name=Garfinkle2025/> while GQ Lupi b is over double<ref name=Demars2023/> or triple this.<ref name=Cugno2024/>

===Mass=== In the early years following its discovery, the models of thermal evolution for substellar objects, used to infer a mass estimate for such objects based on their luminosities (or temperatures) and ages, were not calibrated to objects as young as GQ Lupi, which combined with uncertainties on the luminosity, made its mass very uncertain.<ref name=Seifahrt2007/><ref name=Neuhauser2008/> Taking the age of the companion as 1.1&nbsp;Myr and the luminosity as {{val|4.3|6.7|2.6|e=-3|ul=solar luminosity}}, the discovery paper derived a mass of {{jupiter mass|1{{snd}}42}} based on the combination of three evolutionary models. One of these models, from Wuchterl & Tscharnuter (2003), were consistent with an object of just {{jupiter mass|1{{snd}}2}}.<ref name=Neuhauser2005/> This estimate assumed that the object formed in a [[protoplanetary disk]] and was subsequently challenged as such a formation scenario would need at least a million years, in tension with the estimated age of the system.<ref name=Janson2006/>{{rp|6}} Janson ''et al.'' (2006) derived masses between {{jupiter mass|12 and 40}} based on GQ Lup b's luminosity, and between {{jupiter mass|3 and 20}} based on its [[effective temperature]] of {{val|1200|-|2500|ul=K}}.<ref name=Janson2006/> Marois ''et al.'' (2006) then derived masses of {{jupiter mass|15}} and {{jupiter mass|10{{snd}}20}} based on different models and an updated luminosity of {{val|3.80|0.67|0.57|e=-3|u=solar luminosity}}, hence a range of {{jupiter mass|10{{snd}}20}} was adopted.<ref name=Marois2006/>

Seifahrt ''et al.'' (2007) came up with a mass derived independently from evolutionary models, based on the relation of [[surface gravity]], radius, and mass. They arrived at a value of {{jupiter mass|20}}, but due to the uncertainty of both radius and surface gravity, this value is also uncertain, and could be as high as {{jupiter mass|155}} and as low as {{jupiter mass|4}}. The upper range was narrowed down to {{jupiter mass|36}} based on comparisons to the brown dwarf [[2M0535-05]]&nbsp;B, which it was thought to be coeval with GQ Lupi B at 1&nbsp;[[Myr]] and had its mass ({{jupiter mass|36}}) and radius ({{jupiter radius|5.0}}) measured independently from the models.<ref name=Seifahrt2007/> Based on the same calculations of Seifahrt ''et al.'' (2007) and an updated radius, Neuhäuser ''et al.'' (2008) derived a nominal value of {{jupiter mass|20}} with a lower value of a {{jupiter mass|few}} and a upper value constrained by the comparisons with 2M0535-05&nbsp;B. The nominal value agreed with the expectations of evolutionary models, but the uncertainties on such models still allowed for highly different values. The mass estimates from this epoch were thus consistent with GQ Lupi b being either a lower-mass [[gas giant]] [[exoplanet]] (which would give it the designation {{nobr|GQ Lup b}}<ref name=Seifahrt2007/>) or a higher-mass [[brown dwarf]] (which would give it the designation {{nobr|GQ Lup B}}<ref name=Seifahrt2007/>).<ref name=Neuhauser2008/>

In the years that followed, updated and more robust evolutionary models, precise measurements of the distance by the [[Gaia spacecraft]] resulting in accurate luminosity measurements, and revised age estimates for the system, helped narrowing down the range of estimated masses.<ref name=Xuan2024/> Stolker ''et al.'' (2021) came up with a mass of {{jupiter mass|30}} based on a revised [[absolute magnitude]] with the Gaia distance, an assumed age of 3&nbsp;Myr that was consistent with a range of {{val|2|-|5}}&nbsp;[[Myr]] derived in 2012, and AMES-Dusty evolutionary models from 2000.<ref name=Stolker2021/>{{rp|2–6, 12}} While this value was considered uncertain, other parameters derived with the same model showed agreement with those from atmospheric models.<ref name=Stolker2021/>{{rp|12}} Using an [[effective temperature]] of {{Val|2638|33|51|ul=K}} and an age between 2 and 5&nbsp;Myr, Demars ''et al.'' (2023) obtained a mass of {{val|22|2|3|u=Jupiter mass}} based on ATMO evolutionary tracks (2015).<ref name=Demars2023/> Using the updated luminosity from the Gaia distance ({{Val|7.08|1.83|1.46|e=-3|ul=solar luminosity}}) and an age of {{Val|2.5|1.5|0.9}}&nbsp;Myr, Xuan ''et al.'' (2024) derived a mass of {{val|33|10|u=Jupiter mass}} based on four evolutionary models which "have been shown to reasonably reproduce the bulk properties of benchmark substellar companions with dynamical masses".<ref name=Xuan2024/> Kammerer ''et al.'' (2025), adopting an age of {{val|3.5|1.5}}&nbsp;Myr and a luminosity of {{Val|3.24|0.86|1.03|e=-3|u=solar luminosity}} derived from a single passband, obtained {{Val|26.4|2.9|3.8|u=Jupiter mass}} from evolutionary models.<ref name=Kammerer2025/>

While improvements in the evolutionary models and the inclusion of brown dwarf binaries increased the robustness of the mass estimates, all of them are based on differing age estimates and the models still remain largely uncalibrated at the youngest ages and planetary masses. This is well visible in the case of GQ Lup b in differences of up to about 40% in best mass estimates like ~{{val|20|10}}<ref name="Sun2024"/> vs. {{val|33|10}}<ref name=Xuan2024/> {{Jupiter mass}}, both published in 2024, partially remaining large error ranges like 10{{snd}}40 {{Jupiter mass}},<ref name=Stolker2021/><ref name=Venkatesan2025/> as well as higher mass despite lower age estimate ({{val|33|10|u=Jupiter mass}} at {{Val|2.5|1.5|0.9}}&nbsp;Myr)<ref name="Xuan2024" /> vs. lower mass despite higher age estimate ({{Val|26.4|2.9|3.8|u=Jupiter mass}} at {{val|3.5|1.5}}&nbsp;Myr).<ref name="Kammerer2025" />

===Radius=== The first estimate of the radius was performed by the discovery paper. By comparing their low-resolution spectrum to atmosphere models and assuming a distance of {{convert|140|pc|ly}} based on membership to the Lupus I cloud, they found a best-fit radius of {{val|2|ul=Jupiter radius}}.<ref name=Neuhauser2005/> In 2006, Marois ''et al.'' derived a radius of {{Val|3.7|0.5|u=Jupiter radius}} by comparing the obtained spectrum to model atmospheres and assuming the same distance.<ref name=Marois2006/> In 2007, Seifahrt ''et al.'' found a radius of {{Val|3.50|1.50|1.03|u=Jupiter radius}} based on the estimated luminosity and [[effective temperature]],<ref name=Seifahrt2007/> while Neuhäuser ''et al.'' (2008) refined it to {{Val|3.0|0.5|u=Jupiter radius}} based on a more precise luminosity.<ref name=Neuhauser2008/>

In 2012, Patience ''et al.'' inferred radii between {{jupiter radius|4.4 and 8.6}} as a way to match the best-fitting model atmosphere to the observed brightness.<ref name=Patience2012/> Zhou ''et al.'' (2014) arrived at an estimate of {{Val|4.6|1.4|u=Jupiter radius}} by scaling synthetic spectra to the [[spectral energy distribution]] (SED).<ref name=Zhou2014/>

Stolker ''et al.'' (2021) analysed the full spectral energy distribution of GQ Lupi b and obtained a radius of {{val|3.77|u=Jupiter radius}} from an atmosphere model taking in account [[interstellar extinction]] and the surrounding [[circumplanetary disk|protolunar disk]].<ref name=Stolker2021/> Demars ''et al.'' (2023) obtained a mass of {{Val|4.20|0.25|0.13|u=Jupiter radius}} from their best-fit atmospheric model, but they note that evolutionary tracks would predict a smaller radius of {{Val|2.65|-|3.3|u=Jupiter radius}}. This could be due to evolutionary tracks not capturing the physics of GQ Lupi b such as [[deuterium burning]], but is more likely to be to an inaccurate estimate of the extinction in the atmospheric model. They note this discrepancy is not unique to GQ Lupi b and might indicate that it is a close binary of nearly identical components in terms of luminosity and temperature, which would result in a radius of {{jupiter radius|3}} for each and agree with evolutionary tracks.<ref name=Demars2023/> Radial velocity measurements have not detected such a companion.<ref name=Horstman2024/>

Cugno ''et al.'' (2024) found radii of {{Val|3.60|0.03|u=Jupiter radius}} and {{Val|3.67|0.02|u=Jupiter radius}}, by analysing the spectral energy distribution of the companion with the best-fitting atmospheric models that take in account the contributions of the circumplanetary disk, which are stronger at longer wavelengths, and [[Accretion (astrophysics)|accretion]].<ref name=Cugno2024/> Xuan ''et al.'' (2024) obtained a radius of {{val|3.7|0.7|ul=Jupiter radius}} based on evolutionary models adopting a system age of {{Val|2.5|1.5|0.9}}&nbsp;[[Myr]] and a luminosity of {{Val|7.08|1.83|1.46|e=-3|ul=solar luminosity}}.<ref name=Xuan2024/>

===Effective temperature=== The first temperature measurement was performed by the discovery paper by comparing the spectrum to model atmospheres, which resulted in {{Val|2000|ul=K}}.<ref name=Neuhauser2005/> Marois ''et al.'' (2006) used the same technique and obtained {{Val|2335|100|u=K}} with their spectra.<ref name=Marois2006/> The same was done by Seifahrt ''et al.'' (2007) who obtained {{Val|2650|100|u=K}}.<ref name=Seifahrt2007/>

Stolker ''et al.'' (2021) obtained {{Val|2700|u=K}} by comparing the full [[spectral energy distribution]] (SED) of GQ Lupi b to an atmosphere model taking in account [[interstellar extinction]] and the surrounding [[circumplanetary disk|disk]].<ref name=Stolker2021/> Demars ''et al.'' (2023) obtained {{Val|2638|33|51|u=K}} from their best-fit atmospheric model.<ref name=Demars2023/> Cugno ''et al.'' (2024) obtained {{Val|2717|14|u=K}} and {{Val|2719|14|u=K}} by comparing the SED to the best-fitting atmospheric models that take in account the surrounding disk and [[Accretion (astrophysics)|accretion]].<ref name=Cugno2024/>

==Formation== There are at least three formation pathways that can form a gas giant substellar companion: bottom-up accretion in a [[protoplanetary disk]] (also called [[Core-accretion theory|core accretion]]), gravitational instability in a [[circumstellar disk]] or the fragmentation of a molecular cloud, both of which are 'top-down' channels.<ref name=Xuan2024/>{{rp|1, 2}} The first two mechanisms are able to generate giant planets and objects beyond the [[Deuterium fusion|deuterium burning]] limit in the protoplanetary disk, while the last one is considered a stellar formation mechanism, that can form objects of planetary mass, brown dwarfs or stars.

GQ Lupi b has most likely formed through cloud fragmentation, similar to a star (in this case a failed star)<ref name=Venkatesan2025/><ref name=Holstein2021/> or by disk instability, like a planet within the disk (in this case a brown dwarf or exoplanet).<ref name="Gonzalez2025" /><ref name=Stamatellos2015 /> Its [[circumplanetary disk]] is likely misaligned with the circumstellar disk of GQ Lupi, which is consistent with formation through collapse of a molecular cloud, similar to stars, or through instability in the circumstellar disk, if the object formed far from the disk's midplane or if the disk is originally asymmetric.<ref name=Holstein2021/>{{rp|19}} Measurements of the companion's orbit have found it to be misaligned with the host star's disk and spin axis, and to be mildly [[orbital eccentricity|eccentric]], which in combination with the chemical composition, points toward formation through cloud fragmentation.<ref name=Venkatesan2025/> Its formation mechanism is, however, not yet unequivocally determined, as the companion's {{SimpleNuclide|Carbon|12}}/{{SimpleNuclide|Carbon|13}} isotope ratio and C/O ratio are roughly the same as for the host star, which is consistent with both objects having formed from a shared material reservoir, so either forming through cloud fragmentation or disk instability,<ref name="Gonzalez2025" />{{rp|1}} and the latter formation mechanism is suggested by its higher than expected accretion rate.<ref name="Stamatellos2015" />

==See also== * [[DH Tauri b]] * [[List of largest exoplanets]]

==Notes== {{notelist}}

==References== {{reflist|refs=

<ref name=Neuhauser2005>{{Cite journal |last1=Neuhäuser |first1=R. |last2=Guenther |first2=E. W. |last3=Wuchterl |first3=G. |last4=Mugrauer |first4=M. |last5=Bedalov |first5=A. |last6=Hauschildt |first6=P. H. |date=2005-05-01 |title=Evidence for a co-moving sub-stellar companion of GQ Lup |journal=Astronomy & Astrophysics |language=en |volume=435 |issue=1 |pages=L13–L16 |doi=10.1051/0004-6361:200500104 |arxiv=astro-ph/0503691 |bibcode=2005A&A...435L..13N |issn=0004-6361}}</ref>

<ref name=eso>{{Cite web |title=Is this a Brown Dwarf or an Exoplanet? New Young Sub-stellar Companion Imaged with the VLT |url=http://www.eso.org/public/outreach/press-rel/pr-2005/pr-09-05.html |date=2005-04-07 |url-status=dead |archive-url=https://web.archive.org/web/20080507074340/http://www.eso.org/public/outreach/press-rel/pr-2005/pr-09-05.html |archive-date=2008-05-07 |access-date=2008-06-13 |website=[[European Southern Observatory]]}}</ref>

<ref name=Stolker2021>{{Cite journal |last1=Stolker |first1=Tomas |last2=Haffert |first2=Sebastiaan Y. |last3=Kesseli |first3=Aurora Y. |last4=van Holstein |first4=Rob G. |last5=Aoyama |first5=Yuhiko |last6=Brinchmann |first6=Jarle |last7=Cugno |first7=Gabriele |last8=Girard |first8=Julien H. |last9=Marleau |first9=Gabriel-Dominique |last10=Meyer |first10=Michael R. |last11=Milli |first11=Julien |last12=Quanz |first12=Sascha P. |last13=Snellen |first13=Ignas A. G. |last14=Todorov |first14=Kamen O. |date=2021-12-01 |title=Characterizing the Protolunar Disk of the Accreting Companion GQ Lupi B |journal=The Astronomical Journal |volume=162 |issue=6 |pages=286 |doi=10.3847/1538-3881/ac2c7f |doi-access=free |arxiv=2110.04307 |bibcode=2021AJ....162..286S |issn=0004-6256}}</ref>

<ref name=Janson2006>{{Cite journal |last1=Janson |first1=M. |last2=Brandner |first2=W. |last3=Henning |first3=T. |last4=Zinnecker |first4=H. |date=2006-07-01 |title=Early ComeOn+ adaptive optics observation of GQ Lupi and its substellar companion |journal=Astronomy & Astrophysics |language=en |volume=453 |issue=2 |pages=609–614 |doi=10.1051/0004-6361:20054475 |arxiv=astro-ph/0603228 |bibcode=2006A&A...453..609J |issn=0004-6361}}</ref>

<ref name=Marois2006>{{Cite journal |last1=Marois |first1=Christian |last2=Macintosh |first2=Bruce |last3=Barman |first3=Travis |date=2006-12-28 |title=GQ Lup B Visible and Near-Infrared Photometric Analysis |journal=The Astrophysical Journal |language=en |volume=654 |issue=2 |pages=L151–L154 |doi=10.1086/511071 |issn=0004-637X|arxiv=astro-ph/0610058 }}</ref>

<ref name=Seifahrt2007>{{Cite journal |last1=Seifahrt |first1=A. |last2=Neuhäuser |first2=R. |last3=Hauschildt |first3=P. H. |date=2007-02-01 |title=Near-infrared integral-field spectroscopy of the companion to GQ Lupi |journal=Astronomy & Astrophysics |language=en |volume=463 |issue=1 |pages=309–313 |doi=10.1051/0004-6361:20066463 |arxiv=astro-ph/0612250 |bibcode=2007A&A...463..309S |issn=0004-6361}}</ref>

<ref name=Neuhauser2008>{{Cite journal |last1=Neuhäuser |first1=R. |last2=Mugrauer |first2=M. |last3=Seifahrt |first3=A. |last4=Schmidt |first4=T. O. B. |last5=Vogt |first5=N. |date=2008-06-01 |title=Astrometric and photometric monitoring of GQ Lupi and its sub-stellar companion |journal=Astronomy & Astrophysics |language=en |volume=484 |issue=1 |pages=281–291 |doi=10.1051/0004-6361:20078493 |arxiv=0801.2287 |bibcode=2008A&A...484..281N |issn=0004-6361}}</ref>

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==External links== {{commonscat-inline}} *{{cite encyclopedia |url=https://exoplanet.eu/catalog/gq_lup_b--238/ |encyclopedia=[[Extrasolar Planets Encyclopaedia]] |title=GQ Lup b |access-date=2008-06-09 }} *{{cite web |url=http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=GQ+Lup&NbIdent=1&Radius=10&Radius.unit=arcmin&CooFrame=FK5&CooEpoch=2000&CooEqui=2000&output.max=all&o.catall=on&output.mesdisp=N&Bibyear1=1983&Bibyear2=2006&Frame1=FK5&Frame2=FK4&Frame3=G&Equi1=2000.0&Equi2=1950.0&Equi3=2000.0&Epoch1=2000.0&Epoch2=1950.0&Epoch3=2000.0 |title=V* GQ Lup |access-date=2008-06-09 |work= SIMBAD}} *{{cite web |url=https://www.newscientist.com/article.ns?id=dn7225 |title=First image of exoplanet orbiting Sun-like star |access-date=2008-06-09 |work=New Scientist |date=2005-04-04 |first=Kelly |last=Young}} *{{cite web |url=https://news.bbc.co.uk/2/hi/uk_news/wales/4408187.stm |title=Telescopes see 'distant planet' |access-date=2008-06-09 |work=BBC News |date=2005-04-04}} *{{cite web |url=http://www.space.com/scienceastronomy/050430_exoplanet_image.html |title=Fresh Debate over First Photo of Extrasolar Planet |access-date=2008-06-09 |work=SPACE.com |date=2005-04-30 |first=Robert Roy |last=Britt}} {{-}}

[[Category:Lupus (constellation)]] [[Category:Exoplanets detected by direct imaging]] [[Category:Exoplanets discovered in 2005]] [[Category:Brown dwarfs]] [[Category:M-type brown dwarfs]]