An gano Gliese 436 b a watan Agusta 2004 ta R. Paul Butler da Geoffrey Marcy na Cibiyar Carnegie na Washington da Jami'ar California, Berkeley, ta amfani da hanyar saurin radial. Tare da 55 Cancri e, shi ne na farko na sabon nau'in taurari tare da mafi ƙarancin taro (M sini) kama da Neptune. An yi rikodin duniyar don wucewa ta tauraronta ta hanyar tsari na atomatik a NMSU a ranar 11 ga Janairu, 2005, amma wannan taron bai yi la'akari da shi ba a lokacin. A shekara ta 2007, Gillon ya jagoranci tawagar da ta lura da wucewar, tana kiwon diski mai tauraro dangane da Duniya. Binciken wucewa ya haifar da ƙayyadadden ainihin taro da radius, duka biyu suna da kama da na Neptune, suna sa Gliese 436 b a lokacin mafi ƙarancin duniyar da aka sani.
Agusta shekara ta 2004