# List of exoplanet extremes

The following are lists of extremes among the known exoplanets. The properties listed here are those for which values are known reliably. The study of exoplanets is one of the most dynamic emerging fields of science, thus these values may change as new discoveries are made.

## Extremes from Earth's viewpoint

| Title | Planet | Star | Data | Notes |
| Most distant discovered | SWEEPS-11 / SWEEPS-04 | SWEEPS J175902.67−291153.5 / SWEEPS J175853.92−291120.6 | 27 700 light-years | Assuming the largest distance from the microlensing light-curve, the planet OGLE-2017-BLG-0364Lb might be more distant, at around 32 600 light-years (10 000 pc). PSR J0738-4042 at 37 000 ly was shown to be affected by a disk of asteroids but no planets have been detected yet. The most distant potentially habitable planet confirmed is Kepler-1606b, at 2870 light-years distant, although the unconfirmed planet KOI-5889.01 is over 5000 light-years distant. On 31 March 2022, K2-2016-BLG-0005Lb was reported to be the most distant exoplanet discovered by the Kepler telescope, at 17 000 light-years away. Among rogue planets, the furthest are very likely extragalactic planets within the lensing system SDSS J1004+4112 at 6.3 billion light-years. |
| Least distant | Proxima Centauri b | Proxima Centauri | 4.25 light-years | Proxima Centauri b is the closest potentially habitable exoplanet known. As Proxima Centauri is the closest star to the Sun (and will stay so for the next 25 000 years), this is an absolute record. |
| Most distant directly visible | CT Chamaeleontis b | CT Chamaeleontis | 622 light-years | The disputed planet candidate CVSO 30 c may be more distant, at 1200 light-years away. Among rogue planets, o005 s41280 is the most distant at 17 300 light-years, followed by o006 s00089, at 6520 light-years away. As brown dwarf candidates, both of them might not be considered as planets, although their masses might be below 13 M$_J$. |
| Closest directly visible | Epsilon Indi Ab | Epsilon Indi | 12.05 light-years | COCONUTS-2b at 35.5 light-years is the next closest directly visible. |
| Star with the brightest apparent magnitude with a planet | Alpha Arietis b | Hamal | Apparent magnitude is 2.005 | Alpha Centauri A (apparent magnitude 0.01) has a directly imaged candidate planet. The evidence of planets around Vega with an apparent magnitude of 0.03 is strongly suggested by circumstellar disks surrounding it. As of 2021, a candidate planet around Vega has been detected. Aldebaran (apparent magnitude varies between 0.75 and 0.95) was thought to have a candidate planet, however later studies found the existence of the planet inconclusive. Similarly, Pollux (apparent magnitude = 1.14) and Mirfak (apparent magnitude = 1.806) were claimed to have orbiting planets, both of which have been questioned. An Earth-mass planet claimed to orbit Alpha Centauri B (apparent magnitude = 1.33) was subsequently refuted. A 2023 study detected 10 luminous point sources around the primary star of Fomalhaut system (apparent magnitude = 1.16), of which the last source may or may not be a planetary-mass companion. This star was previously thought to harbour a directly-imaged planet named Fomalhaut b, before the realization of object as an expanding debris cloud from a planetesimal collision. |
| Star with the faintest apparent magnitude with a planet | MOA-bin-29Lb | MOA-bin-29L | Apparent magnitude is 44.61 | |
| Closest planet to the celestial north pole (i.e. highest declination) | TOI-1691 b | TOI-1691 | Declination of +86° 51′ 37.23″ | |
| Closest planet to the celestial south pole (i.e. lowest declination) | HD 110082 b | HD 110082 | Declination of −88° 07′ 16″ | |
| Star with the highest apparent motion (i.e, proper motion) with a planet | Barnard's Star planets | Barnard's Star | 10.358 arcsec/yr | As Barnard's Star has the highest apparent motion in the sky, this is currently an absolute record. |
| Largest angular distance separation from its host star | COCONUTS-2b | COCONUTS-2 | 594 arcseconds | A candidate planet or brown dwarf around BD+29 5007 has an even larger angular separation of about 935 arcseconds. |
| Smallest angular distance separation from its parent star | SWIFT J1756.9−2508 b | SWIFT J1756.9−2508 | 0.34 microarcseconds | Derived from its separation of 0.00269 AU and its distance of ~26 000 light-years (8000 parsecs). |
| Star with the largest apparent size (angular diameter) | Alpha Arietis b | Hamal | 7.006±0.027 mas | Accounted for the limb darkening effect. Several stars have a larger angular diameter and were claimed to have candidate planets: Aldebaran (20.58±0.03 mas), L2 Puppis (17.9±1.6 mas) and Alpha Centauri A (8.314±0.016 mas). |

## Planetary characteristics

| Title | Planet | Star | Data | Notes |
| Most massive | The most massive planet is difficult to define due to the blurry line between planets and brown dwarfs. If the borderline is defined as the deuterium fusion threshold (roughly 13 M$_J$ at solar metallicity), the most massive planets are those with true mass closest to that cutoff; if planets and brown dwarfs are differentiated based on formation, their mass ranges overlap.$^{:62}$ A candidate for the most massive object that formed in a protoplanetary disk is CWW 89Ab, at about 36 M$_J$. This object is massive enough to have fused deuterium early in its life, but its atmosphere indicates it may have formed via the very high-mass end of the planet formation process. | The most massive planet is difficult to define due to the blurry line between planets and brown dwarfs. If the borderline is defined as the deuterium fusion threshold (roughly 13 M$_J$ at solar metallicity), the most massive planets are those with true mass closest to that cutoff; if planets and brown dwarfs are differentiated based on formation, their mass ranges overlap.$^{:62}$ A candidate for the most massive object that formed in a protoplanetary disk is CWW 89Ab, at about 36 M$_J$. This object is massive enough to have fused deuterium early in its life, but its atmosphere indicates it may have formed via the very high-mass end of the planet formation process. | The most massive planet is difficult to define due to the blurry line between planets and brown dwarfs. If the borderline is defined as the deuterium fusion threshold (roughly 13 M$_J$ at solar metallicity), the most massive planets are those with true mass closest to that cutoff; if planets and brown dwarfs are differentiated based on formation, their mass ranges overlap.$^{:62}$ A candidate for the most massive object that formed in a protoplanetary disk is CWW 89Ab, at about 36 M$_J$. This object is massive enough to have fused deuterium early in its life, but its atmosphere indicates it may have formed via the very high-mass end of the planet formation process. | The most massive planet is difficult to define due to the blurry line between planets and brown dwarfs. If the borderline is defined as the deuterium fusion threshold (roughly 13 M$_J$ at solar metallicity), the most massive planets are those with true mass closest to that cutoff; if planets and brown dwarfs are differentiated based on formation, their mass ranges overlap.$^{:62}$ A candidate for the most massive object that formed in a protoplanetary disk is CWW 89Ab, at about 36 M$_J$. This object is massive enough to have fused deuterium early in its life, but its atmosphere indicates it may have formed via the very high-mass end of the planet formation process. |
| Most massive in proportion to the mass of the star(s) it revolves around | 2M1207 b | 2M1207 | Mass ratio is ~0.2 | May be a sub-brown dwarf instead of a planetary-mass companion. |
| Least massive | PSR J0337+1715 (ABC) b | PSR J0337+1715 | 0.0041±0.003 M$_🜨$ | The extrasolar planetesimal WD 1145+017 b is less massive, at 0.00067 M$_E$. |
| Largest radius | DH Tauri b | DH Tauri | 2.7±0.8 R$_J$ | Next largest is PDS 70 b with 2.09$^{+0.23}$ $_{−0.31}$ – 2.72$^{+0.15}$ $_{−0.17}$ R$_J$. Proplyd 133-353 is larger at up to 7.4±0.3 – 8.0±1.1 R$_J$. It might be considered as a sub-brown dwarf or a rogue planet, with a photoevaporating disk. The largest transiting planet known is XO-6b at 2.17 ± 0.2 R$_J$. |
| Smallest radius | Kepler-37b | Kepler-37 | 0.296±0.037 R$_🜨$ | The extrasolar planetesimal WD 1145+017 b is smaller. |
| Most dense | GP Comae Berenices b | GP Comae Berenices | ≥185 g/cm$^3$ | According to the IAU working definition of exoplanets GP Comae Berenices b, being 10 times more massive than Jupiter, is a planet, despite that it might have formed as a white dwarf that was stripped down to a planetary-mass object. For reference, it is a lot denser than osmium at 293 K, the densest naturally occurring stable element on Earth. It is suspected that GP Comae Berenices b might be composed of strange matter based on its density. TOI-4603 b is the densest planet which orbits a normal star and is not a potential brown dwarf, with 14.1$^{+1.7}$ $_{−1.6}$ g/cm$^3$. |
| Least dense | Kepler-51d | Kepler-51 | 0.0381±0.0085 g/cm$^3$ | Next least dense are the hot Jupiter HAT-P-67b with about 0.044 g/cm$^3$ and the super-Neptune planet WASP-193b with 0.059 ± 0.014 g/cm$^3$. A predicted highly evaporating planet was proposed to orbit the star FU Orionis north with a density of about 0.0042 g/cm$^3$. |
| Highest planetary rotation rate | Beta Pictoris b | Beta Pictoris | 19.9 ± 1.0 km/s | Value measured at the planetary equator. |
| Hottest (irradiated planet) | KELT-9b | KELT-9 | 4050 ± 180 K(3777 °C) | The candidate planet KOI-2093.03 is hotter, at 6,285 K. A candidate planet was suggested to orbit the central star of the Helix Nebula with an equilibrium temperature of 4,970 K. Kepler-70b and Kepler-70c are often described as the hottest known exoplanets, both at >6800 K (assuming an albedo of 0.1 for both), but their existence are highly doubtful. |
| Hottest (self-luminous) | GQ Lupi b | GQ Lupi | 2650 ± 100 K (2377 °C) | GQ Lupi b may be either a massive planet or a brown dwarf. |
| Coldest | OGLE-2005-BLG-390Lb | OGLE-2005-BLG-390L | 50 K (−223.2 °C) | The disputed planet Proxima Centauri c may be cooler, at 39 K (−234.2 °C). |
| Fastest jetstream wind | WASP-127b | WASP-127 | 33 000 km/h (9200 m/s) | |
| Strongest magnetic field | Tau Boötis b | Tau Boötis | 117±38 G | For comparison, the field strength of Jupiter is 4.17 G. The magnetic field of SIMP J013656.5+093347 is stronger at ~3200 G. As a free-floating object, it might not be considered as a planet. |
| Highest albedo | LTT 9779 b | LTT 9779 | 0.79 ± 0.15 | This is value for the western dayside region, with the overall albedo of dayside being 0.50 ± 0.07. For comparison, Earth is 0.3 and Venus is 0.76. |
| Lowest albedo | TrES-2b | GSC 03549-02811 | Geometric albedo < 1% | Best-fit model for albedo gives 0.04% (0.0004). |
| Youngest | DH Tauri b | DH Tauri | 0.7+0.3 −0.2 Myr | The free-floating planet or sub-brown dwarf Proplyd 133-353 is younger, at 0.5 Myr. However, as a free-floating planet, it does not meet the IAU's working definition of a planet. 2MASS J04414489+2301513 b is listed as the youngest planet in the NASA Exoplanet Archive, at an age of 1 Myr, but fails the mass ratio criterion of the IAU working definition of an exoplanet; the mass ratio with the primary is larger than the L4/L5 limit of stability ≈ 1/25 and the companion is 'more likely to have been produced by cloud core fragmentation' (similar to a star). IRAS 04125+2902 b is the youngest transiting planet at an age of ~3 Myr. CI Tauri c would be the youngest radial velocity planet at an age of 2–3 Myr, if confirmed. |
| Oldest | TOI-157 b | TOI-157 | 12.82+0.73 −1.40 Gyr | The currently accepted age of the universe is around 13.8 billion years. Could alternatively be PSR B1620-26 b with 11.2–12.7 Gyr. Two disproven planets had been thought to orbit the star HIP 11952, whose age is 12.8±2.6 Gyr. The star HE 1523-0901 might be older at 13.2 Gyr and has a candidate planet or brown dwarf. |

## Orbital characteristics

| Title | Planet | Star | Data | Notes |
| Longest orbital period (Longest year) | Gliese 900 b (CW2335+0142) | Gliese 900 | 1.27 million years | COCONUTS-2b previously held this record at 1,100,000 years. |
| Shortest orbital period (Shortest year) | SDSS J1730+5545 b | SDSS J1730+5545 | 0.5866 h (35 minutes) | KOI 1843.03 has the shortest orbit around a main-sequence star (an M dwarf) at 4.25 hours. The candidate planet GALEX 0718+3731 b around a white dwarf has a shorter orbit at 0.0078 day (11.2 minutes). |
| Largest orbital separation | Gliese 900 b (CW2335+0142) | Gliese 900 | 12 000 AU | UCAC4 328-061594 b has an even larger orbital separation (19 000 AU), although its mass (21 M$_J$) is higher than the deuterium burning limit (13 M$_J$). Another candidate around BD+29 5007 has an even larger orbit of about 22 100 AU. There is no consensus about its age and the resulting mass, and it could be a field brown dwarf. The companion of ASASSN-21js has an orbit of 13 000 AU, but it is unknown if it is a brown dwarf or a planet due to its unknown mass. |
| Smallest orbital separation (smallest semi-major axis) | SWIFT J1756.9−2508 b | SWIFT J1756.9−2508 | 0.00123 AU | TOI-6324 b has the smallest orbital separation from a main-sequence star (an M dwarf) at ~0.0043 AU. Although the planet SDSS J1240-0159 b has a smaller semi-major axis of 0.00117 Au, its mass (15 M$_J$) is slightly higher than the deuterium burning limit. The candidate planet GALEX 0718+3731 b has a smaller orbit separation at 0.000834 AU. |
| Most eccentric orbit | HD 20782 b | HD 20782 | 0.950 | Could alternatively be HD 28254 b with an eccentricity at 0.95+0.03 −0.04. The possible planet SGR 1806-20 b has an even higher eccentricity at 0.994. The disproven planet candidate at VB 10 was thought to have a higher eccentricity of 0.98. |
| Highest orbital inclination | HD 204313 e | HD 204313 | 176.092°+0.963° −2.122° | |
| Lowest orbital inclination | HD 331093 b | HD 331093 | >0.3704° | HD 43197 c has the lowest orbital inclination that is not a lower limit, of 11.42°+5.388° −3.07°. |
| Largest semi-amplitude | WASP-18b | WASP-18 | 1814+23 −24 m/s | The planetary-mass object CoRoT-3b has a larger semi-amplitude at 2173±25 m/s however it is likely a brown dwarf rather than a planet. |
| Smallest semi-amplitude | Barnard's Star e | Barnard's Star | 0.221±0.038 m/s | |
| Largest orbit around a single star | COCONUTS-2b | L 34-26 | 7506 AU | Next largest are 2MASS J2126–8140 with 6900 AU and HD 106906 b with ~738 AU. UCAC4 328-061594 b has a significantly larger orbital separation (about 19,000 AU), although its mass (21 M$_J$) is higher than the deuterium burning limit (13 M$_J$). |
| Smallest orbit around binary star | Kepler-47b | Kepler-47 | 0.2877+0.0014 −0.0011 AU | Kepler-1521 b has a smaller orbit with semi-major axis at 0.2347±0.0011 AU. The planet might be circumbinary, as the binarity of host star is suggested but not confirmed. |
| Smallest ratio of semi-major axis of binary star orbit to a planet orbiting one of the stars (S-type planet) | Nu Octantis Ab | Nu Octantis | 2.06 | |
| Largest orbit around binary star | SR 12 c | SR 12 | ≈1100 AU | SR 12 c has a mass of 0.013±0.007 M$_☉$. DT Virginis c, also known as Ross 458 c, at a projected separation of ≈1200 AU, with several mass estimates below the deuterium burning limit, has a latest mass determination of 27±4 M$_J$. The binary 2MASS J0249-0557 AB has a planetary mass companion less massive than 13 M$_J$ at a larger separation of 1950 ± 200 AU, although this companion might have formed as a brown dwarf based on the mass ratio to the primary. |
| Largest orbit around a single star in a multiple star system | DH Tauri b | DH Tauri | ≈330 AU | |
| Largest separation between binary stars with a circumbinary planet | SR 12 c | SR 12 | ≈26 AU | SR 12 c has a mass of 0.013±0.007 M$_☉$ at a projected separation of ≈1100 AU. FW Tauri b orbits at a projected separation of 330±30 AU around a ≈11 AU separated binary. It was shown to be likely a 0.1 M$_☉$ star surrounded by a protoplanetary disk rather than a planetary-mass companion. |
| Largest orbit around three stars | Gliese 900 b (CW2335+0142) | Gliese 900 | 12 000 AU | |
| Closest orbit between stars with a planet orbiting one of the stars (S-type planet) | DMPP-3 Ab | HD 42936 | 1.139 AU | DMPP-3 Ab's semi-major axis is around 0.067 AU. |
| Closest orbit between stars with planets orbiting both the stars | HD 133131 Ab, c and HD 133131 Bb | HD 133131 A and HD 133131 B | 360 AU | |
| Smallest semi-major axis ratio between consecutive planets | Kepler-36b and Kepler-36c | Kepler-36 | 1.11 | Kepler-36b and c have semi-major axes of 0.1153 AU and 0.1283 AU, respectively; hence the planet c is 1.11 times further from star than b. There have been unconfirmed detections of co-orbital pairs of exoplanet, each of which has a semi-major axis ratio of almost 1. |
| Largest semi-major axis ratio between consecutive planets | HD 83443 b and HD 83443 c | HD 83443 | 205.1 | HD 83443 b and c have semi-major axes of 0.039 AU and ~8.0 AU, respectively; hence the planet c is about 205.1 times further from star than b. |
| Highest rate of orbital period decay | Kepler-1658b | Kepler-1658 | 131+20 −22 ms/year | |

## Stellar characteristics

| Title | Planet | Star | Data | Notes |
| Highest metallicity | HD 126614 Ab | HD 126614 A | +0.56 dex | Located in a triple star system. |
| Lowest metallicity | K2-344b | K2-344 | −0.95±0.02 dex | BD+20°2457 may be the lowest-metallicity planet host ([Fe/H]=−1.00); however, the proposed planetary system is dynamically unstable. Planets were announced around even the extremely low-metallicity stars HIP 13044 and HIP 11952; however, these claims have since been disproven. A brown dwarf or planetary-mass companion was announced around the population II star HE 1523-0901, whose metallicity is −2.65±0.22 dex. While the inclination of the companion is not known, if its orbit is nearly face-on, it would be sufficiently massive to become a red dwarf instead. A disputed substellar companion, possibly a Jovian planet, was announced to orbit the B-type subdwarf star HD 149382 with a metallicity of -1.30 dex. |
| Highest stellar mass | b Centauri b | b Centauri | 5 - 6 M$_☉$ | The subgiant star Pipirima has a higher mass of 9.1±0.3 M$_☉$, but its planetary-mass companions Mu2 Scorpii b and (the candidate) c might be either brown dwarfs or planets. The candidate planet M51-ULS-1b and the candidate planemo IGR J12580+0134 b might be the blanets, whose hosts have masses of ≫10 and 9 150 000 Solar masses, respectively. The star Mirfak (at 7.3±0.3 Solar masses) has an unconfirmed orbiting planet. The stars R126 (HD 37974), R66 (HD 268835) and HH 1177 in the Large Magellanic Cloud have masses of 70, 30 and 12 Solar masses and have dust discs but no planets have been detected yet. |
| Lowest stellar mass (main- sequence) | KMT-2021-BLG-1554Lb | KMT-2021-BLG-1554L | 0.08+0.013 −0.014 M$_☉$ | The mass of this star is near the hydrogen burning limit. KMT-2016-BLG-2142L has a lower mass of 0.073+0.117 −0.04 M$_☉$, but the value is highly uncertain. |
| Largest stellar radius | HD 220074 b | HD 220074 | 59.60+5.85 −6.31 R$_☉$ | Other stars, such as HD 18438, Mirach and Delta Virginis are larger, but their substellar companions are more massive than the deuterium burning limit at about 13 M$_J$, and thus might be brown dwarfs rather than exoplanets. Candidate planets were reported around the red giants V Camelopardalis (716±185 R$_☉$), R Fornacis (585 R$_☉$), V Hydrae (430 R$_☉$), R Leonis (320-350 R$_☉$) and L2 Puppis (123±14 R$_☉$). The stars R126 and R66 in the Large Magellanic Cloud have radii of 78 R$_☉$ and 131 R$_☉$ and have dust discs but no planets have been detected yet. |
| Smallest stellar radius | PSR J1211-0633 b | PSR J1211-0633 | 0.0000143 R$_☉$ (9.9 km) | A hypothetical planet was proposed to orbit SGR 1935+2154, whose radius is smaller at 4.35 km (6.25×10$^{−6}$ R$_☉$). |
| Smallest stellar radius (brown dwarf) | TVLM 513-46546b | TVLM 513-46546 | 0.097–0.109 R$_☉$ | Lower than that of any brown dwarf in the NASA Exoplanet Archive. |
| Smallest stellar radius (main-sequence star) | TRAPPIST-1 planets | TRAPPIST-1 | 0.1192±0.0013 R$_☉$ | VB 10 (at 0.102 R$_☉$) has a disproven planet candidate. |
| Highest stellar luminosity | HD 220074 b | HD 220074 | 782.6±20.1 L$_☉$ | This is the most luminous star to host a confirmed planet that is not a potential brown dwarf. The star Mirfak, whose luminosity is 3780 L$_☉$, was claimed to have an orbiting planet with a minimum mass of 6.6 ± 0.2 M$_J$. However, the existence of the planet is doubtful. Candidate planets were reported around the cool giants R Leonis (at 3537 L$_☉$), R Fornacis (at 5800 L$_☉$), BD+20°2457 (at 1479 L$_☉$), V Hydrae (at 18000 L$_☉$), U Equulei (at ~6000 L$_☉$) and L2 Puppis (at 1490±150 L$_☉$). The host star system of the unconfirmed planet M51-ULS-1b has a luminosity of ~261000 L$_☉$. The stars R126, R66 and HH 1177 in the Large Magellanic Cloud have luminosities of 1400000 L$_☉$, 320000 L$_☉$ and 19000 L$_☉$ and have dust discs but no planets have been detected yet. |
| Lowest stellar luminosity (main-sequence star) | TRAPPIST-1 planets | TRAPPIST-1 | 0.0005495 L$_☉$ | |
| Highest stellar rotational velocity | Kappa Andromedae b | Kappa Andromedae | ~176 km/s | The star HIP 64892 rotates slightly faster at v sin(i) = 178 km/s; however its orbiting companion, which weighs at ~29–37 M$_J$ and is listed as a planet by EPE, might be most likely a brown dwarf. The stars 51 Ophiuchi and Phi Leonis rotate at 267±5 km/s and ~254 km/s (respectively) and have dust discs but no planets have been detected yet. |
| Hottest star with a planet | PSR B0943+10 b and c | PSR B0943+10 | 3 100 000 K | Blackbody temperature of a small emitting area at the stellar poles. Suggested to actually be a low-mass quark star. |
| Hottest non-compact star with a planet | NSVS 14256825 planets | NSVS 14256825 | 40 000 K (primary) | NN Serpentis is hotter, with a temperature of 57 000 K for the primary star, but the existence of its planets is disputed. A candidate planet was found orbiting the O-type subdwarf TOI-709, whose effective temperature is higher at 50,000 K. |
| Hottest main-sequence star with a planet | b Centauri b | b Centauri | 18 310 ± 320 K | |
| Coolest star with a planet | TRAPPIST-1 planets | TRAPPIST-1 | 2511 K | Technically the primary components of Oph 162225-240515, CFBDSIR 1458+10, WISE J0336−0143 and WISE 1217+1626 are cooler, but are classified as brown dwarfs. The variable stars R Fornacis at 2100 K and V Camelopardalis at 2414±86 K were both claimed to have a planet candidate. A gas giant planet was found orbiting TVLM 513-46546, which is an ultracool star (2242 K) located close to the brown dwarf/red dwarf mass boundary. |

## System characteristics

| Title | System(s) | Planet(s) (in order from star) | Star(s) | Notes |
| System with most planets | Kepler-90 | 8 | 1 | Tau Ceti currently has no confirmed planetary companion, although it has been proposed that the number of orbiting planets may be 8, 9 or even 10. The four planets Tau Ceti e, f, g and h are considered as strong candidates. HD 10180 has six confirmed planets and potentially three more planets. As a reference, the Solar System has eight verified major planets, alongside multiple dwarf planets (the existence of Planet Nine is yet unconfirmed). |
| System with most planets in habitable zone | TRAPPIST-1 | 7 | 1 | Four planets in this system (d, e, f and g) orbit within the circumstellar habitable zone. |
| System with most planets in exact orbital resonance | HD 110067 | 6 | 3 | Each consecutive pair of the planets b, c, d, e, f and g is locked in the resonance of 3:2, 3:2, 3:2, 4:3 and 4:3, respectively. |
| System with most stars | Kepler-64 | PH1b (Kepler-64b) | 4 | PH1b has a circumbinary orbit. 30 Arietis Bb was believed to be either brown dwarf or a massive gas giant in a quadruple star system before later studies revealing a true mass well above the red dwarf-mass limit of 80 M$_{Jup}$. The planetary mass-companion HIP 81208 Cb will be potentially located in a quadruple star system, if the star Gaia DR3 6020420074469092608 is confirmed to be gravitationally bound to the system. The quintuple and quadruple star systems GG Tauri and HD 98800 both have several protoplanetary disks but no planets have been detected yet. Similarly, the star β$^3$ Tucanae A, located in a sextuple star system, was suggested to have a debris disk with no planets having been found. |
| Multiplanetary system with smallest mean semi-major axis (planets are nearest to their star) | Kepler-42 | b, c, d | 1 | Kepler-42 b, c and d have a semi-major axis of 0.0116, 0.006 and 0.0154 AU, respectively. Kepler-70 b, c and d (all unconfirmed and disputed) have a semi-major axis of only 0.006, 0.0076 and ~0.0065 AU, respectively. |
| Multiplanetary system with largest mean semi-major axis (planets are farthest from their star) | YSES 1 | b, c | 1 | YSES 1 b and c have a semi-major axis of ~162 and ~320 AU, respectively. |
| Multiplanetary system with smallest range of semi-major axis (smallest difference between the star's nearest planet and its farthest planet) | Kepler-42 | b, c, d | 1 | Kepler-42 b, c and d have a semi-major axis of 0.0116, 0.006 and 0.0154 AU, respectively. The separation between closest and furthest is therefore 0.0094 AU. Kepler-70 b, c and d (all unconfirmed and disputed) have a semi-major axis of only 0.006, 0.0076 and ~0.0065 AU, respectively. The separation between closest and furthest is therefore shorter at 0.0016 AU (239,356 km). |
| Multiplanetary system with largest range of semi-major axis (largest difference between the star's nearest planet and its farthest planet) | AB Pictoris | b, c | 1 | AB Pictoris b and c have semi-major axises of ~190 and ~4 AU, respectively. The separation between closest and furthest is thus around 186 AU. Two planetary-mass objects with masses slightly above the deuterium limit Mu2 Scorpii b and c (the later is unconfirmed) have semi-major axises of ~19 and ~242 AU, respectively; hence the range of semi-major axis is about 223 AU. |
| System with smallest total planetary mass | Barnard's Star | d, b, c, e | 1 | The planets d, b, c and e have minimum masses of 0.263, 0.299, 0.335 and 0.193 Earth masses, respectively. For comparison, Mars has a mass of 0.105 Earth masses. |
| System with largest total planetary mass | HR 8799 | b, c, d, e | 1 | Four planets each having masses within the range 5.7 – 9.1 M$_J$. Nu Ophiuchi b and c have minimum masses of 22.206 and 24.662 Jupiter masses, respectively. They are likely brown dwarfs. HD 81817 b and c have masses of 24.1 and ≥22.6 Jupiter masses, respectively. These companions are also likely brown dwarfs. |
| Multiplanetary system with smallest mean planetary mass | Barnard's Star | d, b, c, e | 1 | The planets d, b, c and e have minimum masses of 0.263, 0.299, 0.335 and 0.193 Earth masses, respectively. For comparison, Mars has a mass of 0.105 Earth masses. |
| Multiplanetary system with largest mean planetary mass | Titawin | b, c, d | 2 | The three planets b, c and d have masses of 1.70+0.33 −0.24, 14.0+2.3 −5.3 and 10.2+0.7 −3.3 Jupiter masses, respectively. This results in a mean planetary mass of 5.7 – 9.7 M$_J$. Could alternatively be the system of HR 8799, in which four planets each have masses within the range 5.7 – 9.1 M$_J$. Nu Ophiuchi b and c have minimum masses of 22.206 and 24.662 Jupiter masses, respectively. They are likely brown dwarfs. HD 81817 b and c have masses of 24.1 and ≥22.6 Jupiter masses, respectively. These companions are also likely brown dwarfs. |
| Exo-multiplanetary system with smallest range in planetary mass, log scale (smallest proportional difference between the most and least massive planets) | HD 37124 | b, c, d | 1 | HD 37124 c and d are estimated to have masses of 0.652 and 0.69 Jupiter masses, respectively (hence a ratio of about 1.058 to 1). |
| Exo-multiplanetary system with largest range in planetary mass, log scale (largest proportional difference between the most and least massive planets) | Gliese 676A | d, e, b, c | 2 | Gliese 676A c and d have a mass ratio of about 975 to 1. For comparison, Mercury and Jupiter have a mass ratio of 5780 to 1. The planet KMT-2020-BLG-0414Lc and the super-Earth KMT-2020-BLG-0414Lb have a mass ratio of about 4590 to 1, although at 27.0+4.0 −3.1 Jupiter masses KMT-2020-BLG-0414Lc might or might not be considered as a brown dwarf. |