A rogue planet (also termed a free-floating planet (FFP), isolated planetary-mass object (iPMO), interstellar, nomad, orphan, starless, unbound or wandering planet) is an interstellar object of planetary mass which is not gravitationally bound to any star or brown dwarf. Rogue planets may originate from planetary systems in which they are formed and later ejected, or they can also form on their own, outside a planetary system. The Milky Way alone may have billions to trillions of rogue planets, a range the upcoming Nancy Grace Roman Space Telescope will likely be able to narrow down.
Some planetary-mass objects may have formed in a similar way to stars, and the International Astronomical Union has proposed that such objects be called sub-brown dwarfs. A possible example is Cha 110913−773444, which may have been ejected and become a rogue planet, or formed on its own to become a sub-brown dwarf.
In October 2023, astronomers, based on observations of the Orion Nebula with the James Webb Space Telescope, reported the discovery of pairs of rogue planets, similar in mass to the planet Jupiter, and called JuMBOs (short for Jupiter Mass Binary Objects).
The two first discovery papers use the names isolated planetary-mass objects (iPMO) and Free-floating planets (FFP). Most astronomical papers use either of these terms. The term rogue planet is more often used for microlensing studies, which also often uses the term FFP. A press-release intended for the public might use an alternative name. The discovery of at least 70 FFPs in 2021 for example used the terms rogue planet, starless planet, wandering planet and free-floating planets in different press-releases.
Isolated planetary-mass objects (iPMO) were first discovered in 2000 by the UK team Lucas & Roche with UKIRT in the Orion Nebula. In the same year the Spanish team Zapatero Osorio et al. discovered iPMOs with Keck spectroscopy in the σ Orionis cluster. The spectroscopy of the objects in the Orion Nebula was published in 2001. Both European teams are now recognized for their quasi-simultaneous discoveries. In the year 1999 the Japanese team Oasa et al. discovered objects in Chamaeleon I that were spectroscopically confirmed years later in 2004 by the US team Luhman et al.
In October 2023, astronomers, based on observations of the Orion Nebula with the James Webb Space Telescope, reported the discovery of pairs of rogue planets, similar in mass to the planet Jupiter, and called JuMBOs (short for Jupiter Mass Binary Objects).
There are two techniques to discover free-floating planets: direct imaging and microlensing.
Astrophysicist Takahiro Sumi of Osaka University in Japan and colleagues, who form the Microlensing Observations in Astrophysics and the Optical Gravitational Lensing Experiment collaborations, published their study of microlensing in 2011. They observed 50 million stars in the Milky Way by using the 1.8-metre (5 ft 11 in) MOA-II telescope at New Zealand's Mount John Observatory and the 1.3-metre (4 ft 3 in) University of Warsaw telescope at Chile's Las Campanas Observatory. They found 474 incidents of microlensing, ten of which were brief enough to be planets of around Jupiter's size with no associated star in the immediate vicinity. The researchers estimated from their observations that there are nearly two Jupiter-mass rogue planets for every star in the Milky Way. One study suggested a much larger number, up to 100,000 times more rogue planets than stars in the Milky Way, though this study encompassed hypothetical objects much smaller than Jupiter. A 2017 study by Przemek Mróz of Warsaw University Observatory and colleagues, with six times larger statistics than the 2011 study, indicates an upper limit on Jupiter-mass free-floating or wide-orbit planets of 0.25 planets per main-sequence star in the Milky Way.
In September 2020, astronomers using microlensing techniques reported the detection, for the first time, of an Earth-mass rogue planet (named OGLE-2016-BLG-1928) unbound to any star and free floating in the Milky Way galaxy.
Microlensing planets can only be studied by the microlensing event, which makes the characterization of the planet difficult. Astronomers therefore turn to isolated planetary-mass objects (iPMO) that were found via the direct imaging method. To determine a mass of a brown dwarf or iPMO one needs for example the luminosity and the age of an object. Determining the age of a low-mass object has proven to be difficult. It is no surprise that the vast majority of iPMOs are found inside young nearby star-forming regions of which astronomers know their age. These objects are younger than 200 Myrs, are massive (>5 MJ) and belong to the L- and T-dwarfs. There is however a small growing sample of cold and old Y-dwarfs that have estimated masses of 8-20 MJ. Nearby rogue planet candidates of spectral type Y include WISE 0855−0714 at a distance of 7.27±0.13 light-years. If this sample of Y-dwarfs can be characterized with more accurate measurements or if a way to better characterize their ages can be found, the number of old and cold iPMOs will likely increase significantly.
The first iPMOs were discovered in the early 2000s via direct imaging inside young star-forming regions. These iPMOs found via direct imaging formed probably like stars (sometimes called sub-brown dwarf). There might be iPMOs that form like a planet, which are then ejected. These objects will however be kinematically different from their natal star-forming region, should not be surrounded by a circumstellar disk and have high metallicity. None of the iPMOs found inside young star-forming regions show a high velocity compared to their star-forming region. For old iPMOs the cold WISE J0830+2837 shows a Vtan of about 100 km/s, which is high, but still consistent with formation in our galaxy. For WISE 1534–1043 one alternative scenario explains this object as an ejected exoplanet due to its high Vtan of about 200 km/s, but its color suggests it is an old metal-poor brown dwarf.
Most astronomers studying massive iPMOs believe that they represent the low-mass end of the star-formation process and observations suggest that star-formation is cut off below a certain mass. Observations in star-clusters suggests this cut-off mass is 5 MJ and observations outside star-clusters suggest a cut-off mass of 10 MJ.
Astronomers have used the Herschel Space Observatory and the Very Large Telescope to observe a very young free-floating planetary-mass object, OTS 44, and demonstrate that the processes characterizing the canonical star-like mode of formation apply to isolated objects down to a few Jupiter masses. Herschel far-infrared observations have shown that OTS 44 is surrounded by a disk of at least 10 Earth masses and thus could eventually form a mini planetary system. Spectroscopic observations of OTS 44 with the SINFONI spectrograph at the Very Large Telescope have revealed that the disk is actively accreting matter, similar to the disks of young stars.
In December 2021, the largest ever group of rogue planets was discovered, numbering at least 70 and up to 170 depending on the assumed age. They are found in the OB association between Upper Scorpius and Ophiuchus with masses between 4 and 13 MJ and age around 3 to 10 million years, and were most likely formed by either gravitational collapse of gas clouds, or formation in a protoplanetary disk followed by ejection due to dynamical instabilities. Follow-up observations with spectroscopy from the Subaru Telescope and Gran Telescopio Canarias showed that the contamination of this sample is quite low (≤6%). The 16 young objects had a mass between 3 and 14 MJ, confirming that they are indeed planetary-mass objects.
There are in general two scenarios that can lead to the formation of an isolated planetary-mass object (iPMO). It can form like a planet around a star and is then ejected, or it forms like a low-mass star or brown dwarf in isolation. This can influence its composition and motion.
Formation like a star
Objects with a mass of at least one Jupiter mass were thought to be able to form via collapse and fragmentation of molecular clouds from models in 2001. Observations have shown that objects below 5 MJ are unlikely to form on their own. A particular type of globule, called globulettes, are thought to be birthplaces for brown dwarfs and planetary-mass objects. Globulettes are found in the Rosette Nebula and IC 1805. Sometimes young iPMOs are still surrounded by a disk that could form exomoons. Due to the tight orbit of this type of exomoon around their host planet, they have a high chance of 10-15% to be transiting.
Formation like a planet
Ejected planets are predicted to be mostly low-mass (<30 M🜨 Figure 1 Ma et al.) and their mean mass depends on the mass of their host star. Simulations by Ma et al. did show that 17.5% of 1 M☉ stars eject a total of 16.8 M🜨 per star with a typical (median) mass of 0.8 M🜨 for an individual free-floating planet (FFP). For lower mass red dwarfs with a mass of 0.3 M☉ 12% of stars eject a total of 5.1 M🜨 per star with a typical mass of 0.3 M🜨 for an individual FFP.
Hong et al. predicted that exomoons can be scattered by planet-planet interactions and become ejected exomoons.
Higher mass (0.3-1 MJ) ejected FFP are predicted to be possible, but they are also predicted to be rare.
Interstellar planets generate little heat and are not heated by a star. However, in 1998, David J. Stevenson theorized that some planet-sized objects adrift in interstellar space might sustain a thick atmosphere that would not freeze out. He proposed that these atmospheres would be preserved by the pressure-induced far-infrared radiation opacity of a thick hydrogen-containing atmosphere.
During planetary-system formation, several small protoplanetary bodies may be ejected from the system. An ejected body would receive less of the stellar-generated ultraviolet light that can strip away the lighter elements of its atmosphere. Even an Earth-sized body would have enough gravity to prevent the escape of the hydrogen and helium in its atmosphere. In an Earth-sized object the geothermal energy from residual core radioisotope decay could maintain a surface temperature above the melting point of water, allowing liquid-water oceans to exist. These planets are likely to remain geologically active for long periods. If they have geodynamo-created protective magnetospheres and sea floor volcanism, hydrothermal vents could provide energy for life. These bodies would be difficult to detect because of their weak thermal microwave radiation emissions, although reflected solar radiation and far-infrared thermal emissions may be detectable from an object that is less than 1,000 astronomical units from Earth. Around five percent of Earth-sized ejected planets with Moon-sized natural satellites would retain their satellites after ejection. A large satellite would be a source of significant geological tidal heating.
The table below lists rogue planets, confirmed or suspected, that have been discovered. It is yet unknown whether these planets were ejected from orbiting a star or else formed on their own as sub-brown dwarfs. Whether exceptionally low-mass rogue planets (such as OGLE-2012-BLG-1323 and KMT-2019-BLG-2073) are even capable of being formed on their own is currently unknown.
Discovered via direct imaging
These objects were discovered with the direct imaging method. Many were discovered in young star-clusters or stellar associations and a few old are known (such as W0855). List is sorted after discovery year.
|Spectral type||Status||Stellar assoc. membership||Discovery|
|OTS 44||11.5~||0.5–3||554||M9.5||Likely a low-mass brown dwarf||Chamaeleon I||1998|
|S Ori 52||2–8||1–5||1,150||Age and mass uncertain; may be a foreground brown dwarf||σ Orionis cluster||2000|
|Proplyd 061-401||~11||1||1,344||L4–L5||Candidate, 15 candidates in total from this work||Orion nebula||2001|
|S Ori 70||3||T6||interloper?||σ Orionis cluster||2002|
|Cha 110913-773444||5–15||2~||529||>M9.5||Candidate||Chamaeleon I||2004|
|SIMP J013656.5+093347||11-13||200~||20-22||T2.5||Candidate||Carina-Near moving group||2006|
|UGPS J072227.51−054031.2||0.66–16.02||13||T9||Mass uncertain||none||2010|
|M10-4450||2–3||1||325||T||Candidate||rho Ophiuchi cloud||2010|
|WISE 1828+2650||3–6 or 0.5–20||2–4 or 0.1–10||47||>Y2||candidate, could be binary||none||2011|
|CFBDSIR 2149−0403||4–7||110–130||117–143||T7||Candidate||AB Doradus moving group||2012|
|SONYC-NGC1333-36||~6||1||978||L3||candidate, NGC 1333 has two other objects with masses below 15 MJ||NGC 1333||2012|
|SSTc2d J183037.2+011837||2–4||3||848–1354||T?||Candidate, also called ID 4||Serpens Core cluster (in the Serpens Cloud)||2012|
|PSO J318.5−22||6.24–7.60||21–27||72.32||L7||Confirmed; also known as 2MASS J21140802-2251358||Beta Pictoris Moving group||2013|
|2MASS J2208+2921||11–13||21–27||115||L3γ||Candidate; radial velocity needed||Beta Pictoris Moving group||2014|
|WISE J1741-4642||4–21||23–130||L7pec||Candidate||Beta Pictoris or AB Doradus moving group||2014|
|WISE 0855−0714||3–10||>1,000||7.1||Y4||Age uncertain, but old due to solar vicinity object; candidate even for an old age of 12 Gyrs (age of the universe is 13.8 Gyrs)||none||2014|
|2MASS J12074836–3900043||11–13||7–13||200||L1||Candidate; distance needed||TW Hydrae association||2014|
|SIMP J2154–1055||9–11||30–50||63||L4β||Age questioned||Argus association||2014|
|SDSS J111010.01+011613.1||10.83–11.73||110–130||63||T5.5||Confirmed||AB Doradus moving group||2015|
|2MASS J11193254–1137466 AB||4–8||7–13||~90||L7||Candidate, has a candidate exomoon or variable atmosphere||TW Hydrae Association||2016|
|WISEA 1147||5–13||7–13||~100||L7||Candidate||TW Hydrae Association||2016|
|USco J155150.2-213457||8–10||6.907-10||104||L6||Candidate, low gavity||Upper Scorpius association||2016|
|Proplyd 133-353||<13||1||1,344||M9.5||Candidate with a photoevaporating disk||Orion Nebula||2016|
|Cha J11110675-7636030||3–6||1–3||520–550||M9–L2||Candidate, but could be surrounded by a disk, which would make it a sub-brown dwarf; other candidates from this work||Charmaeleon I||2017|
|PSO J077.1+24||6||1–2||470||L2||Candidate, work also published another candidate in Taurus||Taurus Molecular Cloud||2017|
|2MASS J1324+6358||10.7–11.8||~150||~33||T2||unusually red and unlikely binary; robust candidate||AB Doradus moving group||2007, 2018|
|WISE J0830+2837||4-13||>1,000||31.3-42.7||>Y1||Age uncertain, but old because of high velocity (high Vtan is indicative of an old stellar population), Candidate if younger than 10 Gyrs||none||2020|
|2MASS J0718-6415||3 ± 1||16-28||30.5||T5||Candidate member of the BPMG. Extremely short rotation period of 1.08 hours, comparable to the brown dwarf 2MASS J0348-6022.||Beta Pictoris moving group||2021|
|DANCe J16081299-2304316||3.1–6.3||3–10||104||L6||One of at least 70 candidates published in this work, spectrum similar to HR 8799c||Upper Scorpius association||2021|
|WISE J2255−3118||2.15–2.59||24||~45||T8||very red, candidate||Beta Pictoris moving group||2011,2021|
|WISE J024124.73-365328.0||4.64–5.30||45||~61||T7||candidate||Argus association||2012, 2021|
|2MASS J0013−1143||7.29–8.25||45||~82||T4||binary candidate or composite atmosphere, candidate||Argus association||2017, 2021|
|SDSS J020742.48+000056.2||7.11–8.61||45||~112||T4.5||candidate||Argus association||2002, 2021|
|2MASSI J0453264-175154||12.68–12.98||24||~99||L2.5β||low gravity, candidate||Beta Pictoris moving group||2003, 2023|
|CWISE J0506+0738||7 ± 2||22||104||L8γ–T0γ||Candidate member of the BPMG. Extreme red near-infrared colors.||Beta Pictoris moving group||2023|
Discovered via microlensing
These objects were discovered via microlensing. Rogue planets discovered via microlensing can only be studied by the lensing event and are often also consistent with exoplanets in a wide orbit around an unseen star.
|Exoplanet||Mass (MJ)||Mass (M🜨)||Distance (ly)||Status||Discovery|
|MOA-2011-BLG-262||4~||likely a red dwarf||2013|
|OGLE-2012-BLG-1323||0.0072–0.072||2.3–23||candidate; distance needed||2017|
|OGLE-2017-BLG-0560||1.9–20||candidate; distance needed||2017|
|MOA-2015-BLG-337L||9.85||23,156||may be a binary brown dwarf instead||2018|
|KMT-2019-BLG-2073||0.19||59||candidate; distance needed||2020|
|MOA-9y-5919L||0.0012 or 0.0024||0.37+1.11
−0.27 or 0.75+1.23
|14,700 or 19,300||2023|
- Rogue extragalactic planets – Rogue planets that are outside the Milky Way galaxy
- Intergalactic star – Star not gravitationally bound to any galaxy
- Melancholia – 2011 science fiction drama arthouse film by Lars von Trier in which the titular rogue planet is on a collision course with Earth
- ʻOumuamua, an interstellar object that passed through the Solar System in 2017
- Remina - 2004-5 horror manga by Junji Ito, in which the titular sentient rogue planet sets its sights on Earth to consume it shortly after its discovery
- Rogue comet – A comet not gravitationally bound to any star
- The Wandering Earth
- Tidally detached exomoon
- Shostak, Seth (24 February 2005). "Orphan Planets: It's a Hard Knock Life". Space.com. Retrieved 13 November 2020.
- Lloyd, Robin (18 April 2001). "Free-Floating Planets – British Team Restakes Dubious Claim". Space.com. Archived from the original on 13 October 2008.
- "Orphan 'planet' findings challenged by new model". NASA Astrobiology. 18 April 2001. Archived from the original on 22 March 2009.
- Kirkpatrick, J. Davy; Gelino, Christopher R.; Faherty, Jacqueline K.; Meisner, Aaron M.; Caselden, Dan; Schneider, Adam C.; Marocco, Federico; Cayago, Alfred J.; Smart, R. L.; Eisenhardt, Peter R.; Kuchner, Marc J.; Wright, Edward L.; Cushing, Michael C.; Allers, Katelyn N.; Bardalez Gagliuffi, Daniella C. (1 March 2021). "The Field Substellar Mass Function Based on the Full-sky 20 pc Census of 525 L, T, and Y Dwarfs". The Astrophysical Journal Supplement Series. 253 (1): 7. arXiv:2011.11616. Bibcode:2021ApJS..253....7K. doi:10.3847/1538-4365/abd107. ISSN 0067-0049.
- Neil deGrasse Tyson in Cosmos: A Spacetime Odyssey as referred to by National Geographic
- "The research team found that the mission will provide a rogue planet count that is at least 10 times more precise than current estimates, which range from tens of billions to trillions in our galaxy." https://scitechdaily.com/our-solar-system-may-be-unusual-rogue-planets-unveiled-with-nasas-roman-space-telescope/
- Working Group on Extrasolar Planets – Definition of a "Planet" Position Statement on the Definition of a "Planet" (IAU) Archived 16 September 2006 at the Wayback Machine
- "Rogue planet find makes astronomers ponder theory"
- O’Callaghan, Jonathan (2 October 2023). "The Orion Nebula Is Full of Impossible Enigmas That Come in Pairs - In new, high-resolution imagery of the star-forming region, scientists spotted worlds that defied explanation, naming them Jupiter Mass Binary Objects". The New York Times. Archived from the original on 2 October 2023. Retrieved 2 October 2023.
- Zapatero Osorio, M. R. (6 October 2000). "Discovery of Young, Isolated Planetary Mass Objects in the σ Orionis Star Cluster". Science. 290 (5489): 103–7. Bibcode:2000Sci...290..103Z. doi:10.1126/science.290.5489.103. PMID 11021788.
- Lucas, P. W.; Roche, P. F. (1 June 2000). "A population of very young brown dwarfs and free-floating planets in Orion". Monthly Notices of the Royal Astronomical Society. 314 (4): 858–864. arXiv:astro-ph/0003061. Bibcode:2000MNRAS.314..858L. doi:10.1046/j.1365-8711.2000.03515.x. ISSN 0035-8711. S2CID 119002349.
- Spezzi, L.; Alves de Oliveira, C.; Moraux, E.; Bouvier, J.; Winston, E.; Hudelot, P.; Bouy, H.; Cuillandre, J. -C. (1 September 2012). "Searching for planetary-mass T-dwarfs in the core of Serpens". Astronomy and Astrophysics. 545: A105. arXiv:1208.0702. Bibcode:2012A&A...545A.105S. doi:10.1051/0004-6361/201219559. ISSN 0004-6361. S2CID 119232214.
- Schneider, Adam C. (21 April 2016). "WISEA J114724.10-204021.3: A Free-floating Planetary Mass Member of the TW Hya Association". Astrophysical Journal Letters. 822 (1): L1. arXiv:1603.07985. Bibcode:2016ApJ...822L...1S. doi:10.3847/2041-8205/822/1/L1. S2CID 30068452.
- Liu, Michael C. (10 November 2013). "The Extremely Red, Young L Dwarf PSO J318.5338-22.8603: A Free-floating Planetary-mass Analog to Directly Imaged Young Gas-giant Planets". Astrophysical Journal Letters. 777 (1): L20. arXiv:1310.0457. Bibcode:2013ApJ...777L..20L. doi:10.1088/2041-8205/777/2/L20. S2CID 54007072.
- Bennett, D.P.; Batista, V.; et al. (13 December 2013). "A Sub-Earth-Mass Moon Orbiting a Gas Giant Primary or a High Velocity Planetary System in the Galactic Bulge". The Astrophysical Journal. 785 (2): 155. arXiv:1312.3951. Bibcode:2014ApJ...785..155B. doi:10.1088/0004-637X/785/2/155. S2CID 118327512.
- Mróz, Przemek; et al. (2020). "A Terrestrial-mass Rogue Planet Candidate Detected in the Shortest-timescale Microlensing Event". The Astrophysical Journal Letters. 903 (1). L11. arXiv:2009.12377. Bibcode:2020ApJ...903L..11M. doi:10.3847/2041-8213/abbfad.
- "ESO telescopes help uncover largest group of rogue planets yet". European Southern Observatory. 22 December 2021. Retrieved 22 December 2021.
- "Billions of Starless Planets Haunt Dark Cloud Cradles". NAOJ: National Astronomical Observatory of Japan. 23 December 2021. Retrieved 9 September 2023.
- Shen, Zili (30 December 2021). "Wandering Planets". Astrobites. Retrieved 2 January 2022.
- "Largest Collection of Free-Floating Planets Found in the Milky Way - KPNO". kpno.noirlab.edu. Retrieved 8 September 2023.
- Lucas, P. W.; Roche, P. F.; Allard, France; Hauschildt, P. H. (1 September 2001). "Infrared spectroscopy of substellar objects in Orion". Monthly Notices of the Royal Astronomical Society. 326 (2): 695–721. arXiv:astro-ph/0105154. Bibcode:2001MNRAS.326..695L. doi:10.1046/j.1365-8711.2001.04666.x. ISSN 0035-8711. S2CID 280663.
- Caballero, José A. (1 September 2018). "A Review on Substellar Objects below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs or What?". Geosciences. 8 (10): 362. arXiv:1808.07798. Bibcode:2018Geosc...8..362C. doi:10.3390/geosciences8100362.
- Oasa, Yumiko; Tamura, Motohide; Sugitani, Koji (1 November 1999). "A Deep Near-Infrared Survey of the Chamaeleon I Dark Cloud Core". The Astrophysical Journal. 526 (1): 336–343. Bibcode:1999ApJ...526..336O. doi:10.1086/307964. ISSN 0004-637X. S2CID 120597899.
- Luhman, K. L.; Peterson, Dawn E.; Megeath, S. T. (1 December 2004). "Spectroscopic Confirmation of the Least Massive Known Brown Dwarf in Chamaeleon". The Astrophysical Journal. 617 (1): 565–568. arXiv:astro-ph/0411445. Bibcode:2004ApJ...617..565L. doi:10.1086/425228. ISSN 0004-637X. S2CID 18157277.
- Homeless' Planets May Be Common in Our Galaxy Archived 8 October 2012 at the Wayback Machine by Jon Cartwright, Science Now, 18 May 2011, Accessed 20 May 2011
- Planets that have no stars: New class of planets discovered, Physorg.com, 18 May 2011. Accessed May 2011.
- Sumi, T.; et al. (2011). "Unbound or Distant Planetary Mass Population Detected by Gravitational Microlensing". Nature. 473 (7347): 349–352. arXiv:1105.3544. Bibcode:2011Natur.473..349S. doi:10.1038/nature10092. PMID 21593867. S2CID 4422627.
- "Researchers say galaxy may swarm with 'nomad planets'". Stanford University. 23 February 2012. Retrieved 29 February 2012.
- P. Mroz; et al. (2017). "No large population of unbound or wide-orbit Jupiter-mass planets". Nature. 548 (7666): 183–186. arXiv:1707.07634. Bibcode:2017Natur.548..183M. doi:10.1038/nature23276. PMID 28738410. S2CID 4459776.
- Gough, Evan (1 October 2020). "A Rogue Earth-Mass Planet Has Been Discovered Freely Floating in the Milky Way Without a Star". Universe Today. Retrieved 2 October 2020.
- Redd, Nola Taylor (19 October 2020). "Rogue Rocky Planet Found Adrift in the Milky Way – The diminutive world and others like it could help astronomers probe the mysteries of planet formation". Scientific American. Retrieved 19 October 2020.
- Saumon, D.; Marley, Mark S. (1 December 2008). "The Evolution of L and T Dwarfs in Color-Magnitude Diagrams". The Astrophysical Journal. 689 (2): 1327–1344. arXiv:0808.2611. Bibcode:2008ApJ...689.1327S. doi:10.1086/592734. ISSN 0004-637X. S2CID 15981010.
- Esplin, T. L.; Luhman, K. L.; Faherty, J. K.; Mamajek, E. E.; Bochanski, J. J. (1 August 2017). "A Survey for Planetary-mass Brown Dwarfs in the Chamaeleon I Star-forming Region". The Astronomical Journal. 154 (2): 46. arXiv:1706.00058. Bibcode:2017AJ....154...46E. doi:10.3847/1538-3881/aa74e2. ISSN 0004-6256.
- Gagné, Jonathan (20 July 2015). "SDSS J111010.01+011613.1: A New Planetary-mass T Dwarf Member of the AB Doradus Moving Group". Astrophysical Journal Letters. 808 (1): L20. arXiv:1506.04195. Bibcode:2015ApJ...808L..20G. doi:10.1088/2041-8205/808/1/L20. S2CID 118834638.
- Leggett, S. K.; Tremblin, P.; Esplin, T. L.; Luhman, K. L.; Morley, Caroline V. (1 June 2017). "The Y-type Brown Dwarfs: Estimates of Mass and Age from New Astrometry, Homogenized Photometry, and Near-infrared Spectroscopy". The Astrophysical Journal. 842 (2): 118. arXiv:1704.03573. Bibcode:2017ApJ...842..118L. doi:10.3847/1538-4357/aa6fb5. ISSN 0004-637X.
- Luhman, Kevin L.; Esplin, Taran L. (September 2016). "The Spectral Energy Distribution of the Coldest Known Brown Dwarf". The Astronomical Journal. 152 (2). 78. arXiv:1605.06655. Bibcode:2016AJ....152...78L. doi:10.3847/0004-6256/152/3/78. S2CID 118577918.
- Luhman, Kevin L. (10 February 2005). "Spitzer Identification of the Least Massive Known Brown Dwarf with a Circumstellar Disk". Astrophysical Journal Letters. 620 (1): L51–L54. arXiv:astro-ph/0502100. Bibcode:2005ApJ...620L..51L. doi:10.1086/428613. S2CID 15340083.
- Bardalez Gagliuffi, Daniella C.; Faherty, Jacqueline K.; Schneider, Adam C.; Meisner, Aaron; Caselden, Dan; Colin, Guillaume; Goodman, Sam; Kirkpatrick, J. Davy; Kuchner, Marc; Gagné, Jonathan; Logsdon, Sarah E. (1 June 2020). "WISEA J083011.95+283716.0: A Missing Link Planetary-mass Object". The Astrophysical Journal. 895 (2): 145. arXiv:2004.12829. Bibcode:2020ApJ...895..145B. doi:10.3847/1538-4357/ab8d25. S2CID 216553879.
- Kirkpatrick, J. Davy; Marocco, Federico; Caselden, Dan; Meisner, Aaron M.; Faherty, Jacqueline K.; Schneider, Adam C.; Kuchner, Marc J.; Casewell, S. L.; Gelino, Christopher R.; Cushing, Michael C.; Eisenhardt, Peter R.; Wright, Edward L.; Schurr, Steven D. (1 July 2021). "The Enigmatic Brown Dwarf WISEA J153429.75-104303.3 (a.k.a. "The Accident")". The Astrophysical Journal. 915 (1): L6. arXiv:2106.13408. Bibcode:2021ApJ...915L...6K. doi:10.3847/2041-8213/ac0437. ISSN 0004-637X.
- Joergens, V.; Bonnefoy, M.; Liu, Y.; Bayo, A.; Wolf, S.; Chauvin, G.; Rojo, P. (2013). "OTS 44: Disk and accretion at the planetary border". Astronomy & Astrophysics. 558 (7): L7. arXiv:1310.1936. Bibcode:2013A&A...558L...7J. doi:10.1051/0004-6361/201322432. S2CID 118456052.
- Miret-Roig, Núria; Bouy, Hervé; Raymond, Sean N.; Tamura, Motohide; Bertin, Emmanuel; Barrado, David; Olivares, Javier; Galli, Phillip A. B.; Cuillandre, Jean-Charles; Sarro, Luis Manuel; Berihuete, Angel (22 December 2021). "A rich population of free-floating planets in the Upper Scorpius young stellar association". Nature Astronomy. 6: 89–97. arXiv:2112.11999. Bibcode:2022NatAs...6...89M. doi:10.1038/s41550-021-01513-x. ISSN 2397-3366. S2CID 245385321. See also Nature SharedIt article link; ESO article link
- Raymond, Sean; Bouy, Núria Miret-Roig & Hervé (22 December 2021). "We Discovered a Rogues' Gallery of Monster-Sized Gas Giants". Nautilus. Retrieved 23 December 2021.
- Bouy, H.; Tamura, M.; Barrado, D.; Motohara, K.; Castro Rodríguez, N.; Miret-Roig, N.; Konishi, M.; Koyama, S.; Takahashi, H.; Huélamo, N.; Bertin, E.; Olivares, J.; Sarro, L. M.; Berihuete, A.; Cuillandre, J. -C. (1 August 2022). "Infrared spectroscopy of free-floating planet candidates in Upper Scorpius and Ophiuchus". Astronomy and Astrophysics. 664: A111. arXiv:2206.00916. Bibcode:2022A&A...664A.111B. doi:10.1051/0004-6361/202243850. ISSN 0004-6361. S2CID 249282287.
- Boss, Alan P. (1 April 2001). "Formation of Planetary-Mass Objects by Protostellar Collapse and Fragmentation". The Astrophysical Journal. 551 (2): L167–L170. Bibcode:2001ApJ...551L.167B. doi:10.1086/320033. ISSN 0004-637X. S2CID 121261733.
- Gahm, G. F.; Grenman, T.; Fredriksson, S.; Kristen, H. (1 April 2007). "Globulettes as Seeds of Brown Dwarfs and Free-Floating Planetary-Mass Objects". The Astronomical Journal. 133 (4): 1795–1809. Bibcode:2007AJ....133.1795G. doi:10.1086/512036. ISSN 0004-6256. S2CID 120588285.
- Limbach, Mary Anne; Vos, Johanna M.; Winn, Joshua N.; Heller, René; Mason, Jeffrey C.; Schneider, Adam C.; Dai, Fei (1 September 2021). "On the Detection of Exomoons Transiting Isolated Planetary-mass Objects". The Astrophysical Journal. 918 (2): L25. arXiv:2108.08323. Bibcode:2021ApJ...918L..25L. doi:10.3847/2041-8213/ac1e2d. ISSN 0004-637X.
- Ma, Sizheng; Mao, Shude; Ida, Shigeru; Zhu, Wei; Lin, Douglas N. C. (1 September 2016). "Free-floating planets from core accretion theory: microlensing predictions". Monthly Notices of the Royal Astronomical Society. 461 (1): L107–L111. arXiv:1605.08556. Bibcode:2016MNRAS.461L.107M. doi:10.1093/mnrasl/slw110. ISSN 0035-8711.
- Hong, Yu-Cian; Raymond, Sean N.; Nicholson, Philip D.; Lunine, Jonathan I. (1 January 2018). "Innocent Bystanders: Orbital Dynamics of Exomoons During Planet-Planet Scattering". The Astrophysical Journal. 852 (2): 85. arXiv:1712.06500. Bibcode:2018ApJ...852...85H. doi:10.3847/1538-4357/aaa0db. ISSN 0004-637X.
- Raymond, Sean (9 April 2005). "Life in the dark". Aeon. Retrieved 9 April 2016.
- Stevenson, David J.; Stevens, C. F. (1999). "Life-sustaining planets in interstellar space?". Nature. 400 (6739): 32. Bibcode:1999Natur.400...32S. doi:10.1038/21811. PMID 10403246. S2CID 4307897.
- Lissauer, J. J. (1987). "Timescales for Planetary Accretion and the Structure of the Protoplanetary disk". Icarus. 69 (2): 249–265. Bibcode:1987Icar...69..249L. doi:10.1016/0019-1035(87)90104-7. hdl:2060/19870013947.
- Abbot, Dorian S.; Switzer, Eric R. (2 June 2011). "The Steppenwolf: A proposal for a habitable planet in interstellar space". The Astrophysical Journal. 735 (2): L27. arXiv:1102.1108. Bibcode:2011ApJ...735L..27A. doi:10.1088/2041-8205/735/2/L27. S2CID 73631942.
- Debes, John H.; Steinn Sigurðsson (20 October 2007). "The Survival Rate of Ejected Terrestrial Planets with Moons". The Astrophysical Journal Letters. 668 (2): L167–L170. arXiv:0709.0945. Bibcode:2007ApJ...668L.167D. doi:10.1086/523103. S2CID 15782213.
- Luhman, Kevin L. (10 December 2005). "Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk". Astrophysical Journal Letters. 635 (1): L93–L96. arXiv:astro-ph/0511807. Bibcode:2005ApJ...635L..93L. doi:10.1086/498868. S2CID 11685964.
- Artigau, Étienne; Doyon, René; Lafrenière, David; Nadeau, Daniel; Robert, Jasmin; Albert, Loïc (n.d.). "Discovery of the Brightest T Dwarf in the Northern Hemisphere". The Astrophysical Journal Letters. 651 (1): L57. arXiv:astro-ph/0609419. Bibcode:2006ApJ...651L..57A. doi:10.1086/509146. ISSN 1538-4357. S2CID 118943169.
- Gagné, Jonathan; Faherty, Jacqueline K.; Burgasser, Adam J.; Artigau, Étienne; Bouchard, Sandie; Albert, Loïc; Lafrenière, David; Doyon, René; Bardalez-Gagliuffi, Daniella C. (15 May 2017). "SIMP J013656.5+093347 is Likely a Planetary-Mass Object in the Carina-Near Moving Group". The Astrophysical Journal. 841 (1): L1. arXiv:1705.01625. Bibcode:2017ApJ...841L...1G. doi:10.3847/2041-8213/aa70e2. ISSN 2041-8213. S2CID 119024210.
- Sanghi, Aniket; Liu, Michael C.; Best, William M.; Dupuy, Trent J.; Siverd, Robert J.; Zhang, Zhoujian; Hurt, Spencer A.; Magnier, Eugene A.; Aller, Kimberly M.; Deacon, Niall R. (6 September 2023). "The Hawaii Infrared Parallax Program. VI. The Fundamental Properties of 1000+ Ultracool Dwarfs and Planetary-mass Objects Using Optical to Mid-IR SEDs and Comparison to BT-Settl and ATMO 2020 Model Atmospheres". ApJ: 51. arXiv:2309.03082.
- Sanghi, Aniket; Liu, Michael C.; Best, William M.; Dupuy, Trent J.; Siverd, Robert J.; Zhang, Zhoujian; Hurt, Spencer A.; Magnier, Eugene A.; Aller, Kimberly M.; Deacon, Niall R. (7 September 2023). "Table of Ultracool Fundamental Properties". Zenodo: 1. doi:10.5281/zenodo.8315643.
- Marsh, Kenneth A. (1 February 2010). "A Young Planetary-Mass Object in the ρ Oph Cloud Core". Astrophysical Journal Letters. 709 (2): L158–L162. arXiv:0912.3774. Bibcode:2010ApJ...709L.158M. doi:10.1088/2041-8205/709/2/L158. S2CID 29098549.
- Beichman, C.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Barman, Travis S.; Marsh, Kenneth A.; Cushing, Michael C.; Wright, E. L. (2013). "The Coldest Brown Dwarf (or Free-floating Planet)?: The Y Dwarf WISE 1828+2650". The Astrophysical Journal. 764 (1): 101. arXiv:1301.1669. Bibcode:2013ApJ...764..101B. doi:10.1088/0004-637X/764/1/101. S2CID 118575478.
- Delorme, Philippe (25 September 2012). "CFBDSIR2149-0403: a 4-7 Jupiter-mass free-floating planet in the young moving group AB Doradus?". Astronomy & Astrophysics. 548A: 26. arXiv:1210.0305. Bibcode:2012A&A...548A..26D. doi:10.1051/0004-6361/201219984. S2CID 50935950.
- Scholz, Alexander; Jayawardhana, Ray; Muzic, Koraljka; Geers, Vincent; Tamura, Motohide; Tanaka, Ichi (1 September 2012). "Substellar Objects in Nearby Young Clusters (SONYC). VI. The Planetary-mass Domain of NGC 1333". The Astrophysical Journal. 756 (1): 24. arXiv:1207.1449. Bibcode:2012ApJ...756...24S. doi:10.1088/0004-637X/756/1/24. ISSN 0004-637X. S2CID 119251742.
- "NAME Serpens Cluster". simbad.cds.unistra.fr. Retrieved 7 September 2023.
- Filippazzo, Joseph C.; Rice, Emily L.; Faherty, Jacqueline; Cruz, Kelle L.; Van Gordon, Mollie M.; Looper, Dagny L. (1 September 2015). "Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime". The Astrophysical Journal. 810 (2): 158. arXiv:1508.01767. Bibcode:2015ApJ...810..158F. doi:10.1088/0004-637X/810/2/158. ISSN 0004-637X. S2CID 89611607.
- Gagné, Jonathan (10 March 2014). "BANYAN. II. Very Low Mass and Substellar Candidate Members to Nearby, Young Kinematic Groups with Previously Known Signs of Youth". Astrophysical Journal. 783 (2): 121. arXiv:1312.5864. Bibcode:2014ApJ...783..121G. doi:10.1088/0004-637X/783/2/121. S2CID 119251619.
- Schneider, Adam C. (9 January 2014). "Discovery of the Young L Dwarf WISE J174102.78-464225.5". Astronomical Journal. 147 (2): 34. arXiv:1311.5941. Bibcode:2014AJ....147...34S. doi:10.1088/0004-6256/147/2/34. S2CID 38602758.
- Zapatero Osorio, M. R.; Lodieu, N.; Béjar, V. J. S.; Martín, Eduardo L.; Ivanov, V. D.; Bayo, A.; Boffin, H. M. J.; Muzic, K.; Minniti, D.; Beamín, J. C. (1 August 2016). "Near-infrared photometry of WISE J085510.74-071442.5". Astronomy and Astrophysics. 592: A80. arXiv:1605.08620. Bibcode:2016A&A...592A..80Z. doi:10.1051/0004-6361/201628662. ISSN 0004-6361.
- Luhman, Kevin L. (10 May 2014). "Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun". Astrophysical Journal Letters. 786 (2): L18. arXiv:1404.6501. Bibcode:2014ApJ...786L..18L. doi:10.1088/2041-8205/786/2/L18. S2CID 119102654.
- Gagné, Jonathan (10 April 2014). "The Coolest Isolated Brown Dwarf Candidate Member of TWA". Astrophysical Journal Letters. 785 (1): L14. arXiv:1403.3120. Bibcode:2014ApJ...785L..14G. doi:10.1088/2041-8205/785/1/L14. S2CID 119269921.
- Liu, Michael C. (9 December 2016). "The Hawaii Infrared Parallax Program. II. Young Ultracool Field Dwarfs". Astrophysical Journal. 833 (1): 96. arXiv:1612.02426. Bibcode:2016ApJ...833...96L. doi:10.3847/1538-4357/833/1/96. S2CID 119192984.
- Gagné, Jonathan (1 September 2014). "SIMP J2154-1055: A New Low-gravity L4β Brown Dwarf Candidate Member of the Argus Association". Astrophysical Journal Letters. 792 (1): L17. arXiv:1407.5344. Bibcode:2014ApJ...792L..17G. doi:10.1088/2041-8205/792/1/L17. S2CID 119118880.
- Kellogg, Kendra (11 April 2016). "The Nearest Isolated Member of the TW Hydrae Association is a Giant Planet Analog". Astrophysical Journal Letters. 821 (1): L15. arXiv:1603.08529. Bibcode:2016ApJ...821L..15K. doi:10.3847/2041-8205/821/1/L15. S2CID 119289711.
- Peña Ramírez, K.; Béjar, V. J. S.; Zapatero Osorio, M. R. (1 February 2016). "A new free-floating planet in the Upper Scorpius association". Astronomy and Astrophysics. 586: A157. arXiv:1511.05586. Bibcode:2016A&A...586A.157P. doi:10.1051/0004-6361/201527425. ISSN 0004-6361. S2CID 55940316.
- Fang, Min; Kim, Jinyoung Serena; Pascucci, Ilaria; Apai, Dániel; Manara, Carlo Felice (1 December 2016). "A Candidate Planetary-mass Object with a Photoevaporating Disk in Orion". The Astrophysical Journal Letters. 833 (2): L16. arXiv:1611.09761. Bibcode:2016ApJ...833L..16F. doi:10.3847/2041-8213/833/2/L16. ISSN 0004-637X.
- Best, William M. J.; Liu, Michael C.; Magnier, Eugene A.; Bowler, Brendan P.; Aller, Kimberly M.; Zhang, Zhoujian; Kotson, Michael C.; Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Hodapp, K. W.; Kaiser, N.; Metcalfe, N.; Wainscoat, R. J. (1 March 2017). "A Search for L/T Transition Dwarfs with Pan-STARRS1 and WISE. III. Young L Dwarf Discoveries and Proper Motion Catalogs in Taurus and Scorpius-Centaurus". The Astrophysical Journal. 837 (1): 95. arXiv:1702.00789. Bibcode:2017ApJ...837...95B. doi:10.3847/1538-4357/aa5df0. ISSN 0004-637X.
- Zapatero Osorio, M. R.; Béjar, V. J. S.; Lodieu, N.; Manjavacas, E. (1 March 2018). "Confirming the least massive members of the Pleiades star cluster". Monthly Notices of the Royal Astronomical Society. 475 (1): 139–153. arXiv:1712.01698. Bibcode:2018MNRAS.475..139Z. doi:10.1093/mnras/stx3154. ISSN 0035-8711.
- Gagné, Jonathan; Allers, Katelyn N.; Theissen, Christopher A.; Faherty, Jacqueline K.; Bardalez Gagliuffi, Daniella; Artigau, Étienne (1 February 2018). "2MASS J13243553+6358281 Is an Early T-type Planetary-mass Object in the AB Doradus Moving Group". The Astrophysical Journal. 854 (2): L27. arXiv:1802.00493. Bibcode:2018ApJ...854L..27G. doi:10.3847/2041-8213/aaacfd. ISSN 0004-637X.
- Vos, Johanna M.; Faherty, Jacqueline K.; Gagné, Jonathan; Marley, Mark; Metchev, Stanimir; Gizis, John; Rice, Emily L.; Cruz, Kelle (2022). "Let the Great World Spin: Revealing the Stormy, Turbulent Nature of Young Giant Exoplanet Analogs with the Spitzer Space Telescope". The Astrophysical Journal. 924 (2): 68. arXiv:2201.04711. Bibcode:2022ApJ...924...68V. doi:10.3847/1538-4357/ac4502. S2CID 245904001.
- "The Extrasolar Planet Encyclopaedia – 2MASS J0718-6415". exoplanet.eu. Retrieved 31 January 2021.
- Zhang, Zhoujian; Liu, Michael C.; Best, William M. J.; Dupuy, Trent J.; Siverd, Robert J. (1 April 2021). "The Hawaii Infrared Parallax Program. V. New T-dwarf Members and Candidate Members of Nearby Young Moving Groups". The Astrophysical Journal. 911 (1): 7. arXiv:2102.05045. Bibcode:2021ApJ...911....7Z. doi:10.3847/1538-4357/abe3fa. ISSN 0004-637X.
- Schneider, Adam C.; Burgasser, Adam J.; Bruursema, Justice; Munn, Jeffrey A.; Vrba, Frederick J.; Caselden, Dan; Kabatnik, Martin; Rothermich, Austin; Sainio, Arttu; Bickle, Thomas P.; Dahm, Scott E.; Meisner, Aaron M.; Kirkpatrick, J. Davy; Suárez, Genaro; Gagné, Jonathan (1 February 2023). "Redder than Red: Discovery of an Exceptionally Red L/T Transition Dwarf". The Astrophysical Journal. 943 (2): L16. arXiv:2301.02322. Bibcode:2023ApJ...943L..16S. doi:10.3847/2041-8213/acb0cd. ISSN 0004-637X. S2CID 255522681.
- Mróz, Przemek; Poleski, Radosław; Gould, Andrew; Udalski, Andrzej; Sumi, Takahiro; Szymański, Michał K.; Soszyński, Igor; Pietrukowicz, Paweł; Kozłowski, Szymon; Skowron, Jan; Ulaczyk, Krzysztof; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Hwang, Kyu-Ha; Jung, Youn Kil; Kim, Hyoun-Woo; Ryu, Yoon-Hyun; Shin, In-Gu; Shvartzvald, Yossi; Yee, Jennifer C.; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Seung-Lee; Lee, Chung-Uk; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; et al. (2020), "A terrestrial-mass rogue planet candidate detected in the shortest-timescale microlensing event", The Astrophysical Journal, 903 (1): L11, arXiv:2009.12377, Bibcode:2020ApJ...903L..11M, doi:10.3847/2041-8213/abbfad, S2CID 221971000
- Becky Ferreira (9 November 2018). "Rare Sighting of Two Rogue Planets That Do Not Orbit Stars". Motherboard. Retrieved 10 February 2019.
- Jake Parks (16 November 2018). "These Two New 'Rogue Planets' Wander the Cosmos Without Stars". Discover Magazine. Retrieved 10 February 2019.
- Jake Parks (15 November 2018). "Two free-range planets found roaming the Milky Way in solitude". Astronomy Magazine. Retrieved 10 February 2019.
- Mróz, Przemek; Udalski, Andrzej; Bennett, David P.; Ryu, Yoon-Hyun; Sumi, Takahiro; Shvartzvald, Yossi; Skowron, Jan; Poleski, Radosław; Pietrukowicz, Paweł; Kozłowski, Szymon; Szymański, Michał K.; Wyrzykowski, Łukasz; Soszyński, Igor; Ulaczyk, Krzysztof; Rybicki, Krzysztof (1 February 2019). "Two new free-floating or wide-orbit planets from microlensing". Astronomy and Astrophysics. 622: A201. doi:10.1051/0004-6361/201834557. ISSN 0004-6361.
- "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. Retrieved 4 January 2021.
- Kim, Hyoun-Woo; Hwang, Kyu-Ha; Gould, Andrew; Yee, Jennifer C.; Ryu, Yoon-Hyun; Albrow, Michael D.; Chung, Sun-Ju; Han, Cheongho; Jung, Youn Kil; Lee, Chung-Uk; Shin, In-Gu; Shvartzvald, Yossi; Zang, Weicheng; Cha, Sang-Mok; Kim, Dong-Jin; Kim, Seung-Lee; Lee, Dong-Joo; Lee, Yongseok; Park, Byeong-Gon; Pogge, Richard W. (2021). "KMT-2019-BLG-2073: Fourth Free-floating Planet Candidate with θ e < 10 μas". The Astronomical Journal. 162 (1): 15. arXiv:2007.06870. Bibcode:2021AJ....162...15K. doi:10.3847/1538-3881/abfc4a. S2CID 235445277.
- Mróz, Przemek; et al. (2020), "A Free-floating or Wide-orbit Planet in the Microlensing Event OGLE-2019-BLG-0551", The Astronomical Journal, 159 (6): 262, arXiv:2003.01126, Bibcode:2020AJ....159..262M, doi:10.3847/1538-3881/ab8aeb, S2CID 211817861
- Kaczmarek, Zofia; McGill, Peter; Evans, N. Wyn; Smith, Leigh C.; Wyrzykowski, Łukasz; Howil, Kornel; Jabłońska, Maja (1 August 2022). "Dark lenses through the dust: parallax microlensing events in the VVV". Monthly Notices of the Royal Astronomical Society. 514 (4): 4845–4860. arXiv:2205.07922. Bibcode:2022MNRAS.514.4845K. doi:10.1093/mnras/stac1507. ISSN 0035-8711.
- Koshimoto, Naoki; Sumi, Takahiro; Bennett, David P.; Bozza, Valerio; Mróz, Przemek; Udalski, Andrzej; Rattenbury, Nicholas J.; Abe, Fumio; Barry, Richard; Bhattacharya, Aparna; Bond, Ian A.; Fujii, Hirosane; Fukui, Akihiko; Hamada, Ryusei; Hirao, Yuki (14 March 2023). "Terrestrial and Neptune mass free-floating planet candidates from the MOA-II 9-year Galactic Bulge survey". The Astronomical Journal. 166 (3): 107. arXiv:2303.08279. Bibcode:2023AJ....166..107K. doi:10.3847/1538-3881/ace689.
- "Possibility of Life Sustaining Planets in Interstellar Space" Article by Stevenson similar to the Nature article but with more information.
- Definition of a "Planet" (Resolution B5 – IAU)
- Strange New Worlds Could Make Miniature Solar Systems Robert Roy Britt (SPACE.com) 5 June 2006 11:35 am ET
- The IAU draft definition of "planet" and "plutons" press release (International Astronomical Union) 2006