LTT 9779 b, officially named Cuancoá, is a Neptune-sized planet orbiting the sunlike star LTT 9779, or Uúba. As of 2023, it has the highest-known albedo of any planet.[1]
Characteristics
LTT 9779 b is one of the few known planets in the Neptunian desert.[2] It is highly reflective, with an albedo of 0.8.[3] This makes it the most reflective exoplanet discovered so far. It completes an orbit around LTT 9779 in less than a day, making temperatures on the day side soar to over 2,000 degrees Celsius.[4] Global climate models of the planet indicate it has a very metal-rich atmosphere, with clouds made of silicate likely being present.[1]
Being in the Neptunian desert, LTT 9779 b is a very rare class of planet, with few like it being known. It is estimated that only 1 in 200 Sun-like stars possess a planet with an orbital period of less than a day,[2] and most of those are Hot Jupiters or rocky planets, with ultra-hot Neptune planets being rare.[2] Because of this, LTT 9779 b has been extensively studied by many space telescopes including Hubble and James Webb.
Name
LTT 9779 b was officially named Cuancoá in 2022 by the International Astronomical Union, as part of the NameExoWorlds competition. Cuancoá is a word that refers to the morning star in the Uwa language.[5] Cuancoá's star was named Uúba after the word for "star," "seed," and "eye" in the same language.