Super-Black Planet Absorbs 99% of Light

Artist's rendering of TrES-2b, David A. Aguilar (CfA)

Add TrES-2b to the list of strange exoplanets discovered in recent years. The newly discovered supergiant gas giant is so black only 1% of light it receives is reflected. That’s darker than coal or black paint or closing your eyes and covering them with your hand. It’s blacker than anything found on Earth, even the carbon nanotube construction hailed as the darkest substance ever created. Despite its near-total blackness, the planet emits a faint red glow.

The Jupiter-sized globe is about 750 light-years away and orbits its star at just 3 million miles out–31 times closer than Earth orbits the Sun. This proximity is responsible for the darkness and dim redness of TrES-2b in that it creates surface temperatures of more than 1,800 degrees, while also keeping the planet too hot to form ammonia clouds that would reflect  incoming radiation. The atmosphere comprises vaporized sodium, potassium, and titanium oxide, which trap heat to the planet’s surface.

Even with the weirdness of its atmosphere and the super-close orbit, the planet’s lack of reflection can’t be fully explained yet. There’s something strange afoot on TrES-2b. Astronomers just have to figure out what, exactly.