WASP-49 is abinary star system about 636light-years (195parsecs) away in the constellationLepus. The two stars are separated by 443AU.[6] The primary is aG-type main-sequence star, with a surface temperature of 5,600 K (5,330 °C; 9,620 °F). WASP-49 is depleted of heavy elements relative to the Sun. It has ametallicity Fe/H index of –0.23, meaning it has 59% theiron level of the Sun.[5]
In 2017, WASP-49b was found to have an extensivesodium envelope.[3] A study in 2019 using data from theHubble Space Telescope innear-UV found clear absorption features caused by metals, includingmagnesium and iron. The gaseous magnesium and iron is notgravitationally bound to the planet, but could bemagnetically confined to it.[9][10] The sodium layer around WASP-49b could be due to a tidally-heatedIo-likeexomoon.[11][12] In October 2024, a 5-year study was published indicating that the sodium envelope most likely comes from a distinct body orbiting WASP-49b rather than the star or the planet, although the exact dynamics of the envelope remains to be settled.[13][14]
^Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars".Astronomy and Astrophysics.355:L27 –L30.Bibcode:2000A&A...355L..27H.
^abLendl, M.; Anderson, D. R.; Collier-Cameron, A.; Doyle, A. P.; Gillon, M.; Hellier, C.; Jehin, E.; Lister, T. A.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Smalley, B.; Ségransan, D.; Smith, A. M. S.; Triaud, A. H. M. J.; Udry, S.; West, R. G.; Wheatley, P. J. (2012), "WASP-42 b and WASP-49 b: Two new transiting sub-Jupiters",Astronomy & Astrophysics,544: A72,arXiv:1205.2757,Bibcode:2012A&A...544A..72L,doi:10.1051/0004-6361/201219585,S2CID54186638
