NASA (Exoplanet Catalog artwork)TrES-2b
The darkest known planet, blacker than coal
Overview
TrES-2b is an extrasolar planet orbiting the star TrES-2A located 750 light years away from the Solar System. The planet was identified in 2011 as the darkest known exoplanet, reflecting less than 1% of any light that hits it. Reflecting less light than charcoal, on the surface the planet is said to be pitch black, although it does emit dim red glow due to its temperature. The planet's mass and radius indicate that it is a gas giant with a bulk composition similar to that of Jupiter. Unlike Jupiter, but similar to many planets detected around other stars, TrES-2b is located very close to its star and belongs to the class of planets known as hot Jupiters. This system was within the field of view of the Kepler spacecraft.
Source: Wikipedia
NASA: TrES-2 b is a gas giant exoplanet that orbits a G-type star. Its mass is 1.49 Jupiters, it takes 2.5 days to complete one orbit of its star, and is 0.03568 AU from its star. Its discovery was announced in 2006.
Why it matters
- Reflects less than 1% of the starlight that hits it, as measured by Kepler in 2011.
- Also known as Kepler-1b, the first planet in Kepler's field; its atmosphere glows faintly red from heat.
- Light-absorbing vaporised sodium, potassium and titanium oxide may explain the darkness.
NASA puts it this way: “Are you afraid of the dark? Welcome to TrEs-2b, the planet of eternal night. The darkest planet ever discovered orbiting a star, this alien world is less reflective than coal. Inside its atmosphere, you’d be flying blind in the dark. Some scientists think an eerie deep red glow would emanate from its burning atmosphere.”
Discovery & system
- Discovered
- 2006 · Transit · TrES
- Discovery paper
- O'Donovan et al. 2006
- Discoverers
- Kepler Space Telescope
- Host star
- TrES-2 · G0 V · 5,850 K · 1.36 M☉
- System
- 1 known planet, 2 stars
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| TrES-2 b | 2.47 d | 0.036 AU | 1.36 R♃ | 1.49 M♃ | 1,466 K |
By the numbers
- Radius
- 1.36 R♃15.2 R⊕
- Mass
- 1.49 M♃474 M⊕
- Orbital period
- 2.47 d0.01 yr
- Distance from star
- 0.036 AU5.34 million km
- Eccentricity
- 0nearly circular
- Equilibrium temp.
- 1,466 K1,193 °C
- Starlight received
- 904 × Earth
- Distance from Earth
- 702 ly215.3 pc
- Density
- 0.88 g/cm³0.16 × Earth
Sources
Image: NASA (Exoplanet Catalog artwork) · NASA media: generally free of copyright · image page
Text: Wikipedia (CC BY-SA 4.0). Taglines and highlights are editorial.