List of exoplanet extremes
2MASS J04414489+2301513 b is listed as the youngest planet in the NASA Exoplanet Archive, at an age of 1 Myr,[1] 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[48] and 'more likely to have been produced by cloud core fragmentation' (like a star).[56] A brown dwarf or massive planetary companion was announced around the population II star HE 1523-0901, whose metallicity is −2.65±0.22 dex.[81] A disputed substellar companion, possibly a Jovian planet, was announced to orbit[82] the B-type subdwarf star HD 149382 with a metallicity of -1.30 dex.The bright giant BD+20°2457 (at 1479 L☉[104]) was believed to have two planetary-mass companions orbiting although the claimed system configuration is dynamically unstable.[93] A gas giant planet was found orbiting TVLM 513-46546,[112] which is an ultracool star (2242 K) located very close to the brown dwarf/star mass boundary.[116] 30 Arietis Bb was believed to be either brown dwarf or a massive gas giant in a quadruple star system until later studies revealed a true mass well above 80 MJup.[119] Similarly, the star β3 Tucanae A, located in a sextuple system, was suggested to have a debris disk with no planets having been found.