TrES-2 b
Planet· orbits TrES-2
TrES-2 b (Kepler-1 b) — the DARKEST known planet: a hot Jupiter (1.23 Jupiter radii, ~1.25 Jupiter masses) inferred to reflect LESS THAN 1% of the light that reaches it — darker than coal. It is not truly black, glowing a faint dull red from its own heat, but reflects almost nothing. Because it transits with a measured mass, its density is real. Never imaged.
Open in 3D viewSee TrES-2 b in the live, interactive 3D map
Key facts
Mass
2.38 × 10²⁷ kg
1.25 M♃ (398 M⊕)
Radius
87,792 km
13.8× wider than Earth
Surface gravity
20.6 m/s²
2.1× Earth's gravity
Year
2.47 Earth days
Distance from TrES-2
5,337,652 km
Science
Physical
- Mass
- 2.38 × 10²⁷ kg · 1.25 M♃ (398 M⊕)
- Radius
- 87,792 km · 13.8× wider than Earth
- Öztürk & Erdem 2019 — light-curve solution
- Density
- 839 kg/m³ · 0.84× water
- Computed from mass and radius
- Surface gravity
- 20.6 m/s² · 2.1× Earth's gravity
- Computed from mass and radius
- Escape velocity
- 60.1 km/s · 5.38× Earth's escape velocity
- Computed from mass and radius
Orbital
- Semi-major axis
- 5,337,652 km
- Öztürk & Erdem 2019 (light-curve solution)
- Eccentricity
- 0
- Öztürk & Erdem 2019 (light-curve solution)
- Inclination
- 0.00 °
- Öztürk & Erdem 2019 (light-curve solution)
- Orbital period
- 2.5 days
- Öztürk & Erdem 2019 (light-curve solution)
- Perihelion
- 5,337,652 km
- Computed from the orbital elements
- Aphelion
- 5,337,652 km
- Computed from the orbital elements
- Mean orbital velocity
- 157 km/s
- Computed from the orbital elements
Composition
- Bulk composition
- A hot Jupiter (1.23 Jupiter radii, ~1.25 Jupiter masses, real density from transit + mass). NASA's Kepler measured its reflected light at UNDER 1% of the starlight it receives — the lowest albedo of any planet then known, darker than coal or black paint. It is not truly black (it glows a faint dull red from its own heat) but reflects almost nothing — its dark, hot atmosphere inferred to swallow light. The map shows a near-black Visual impression; Realism a flat spectral colour. Never imaged.
- Cloud appearance
- Appearance based on NASA/JPL-Caltech's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The banded clouds shown are a representation of its class, shown only in Visual mode; Realism shows a plain spectral colour.
Radiation & temperature
- Insolation
- 1,040 S⊕ · 1,040× the sunlight Earth receives
- Computed from TrES-2's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).
- Equilibrium temperature
- 1,466 K (1,193 °C)
- Computed model value — hot enough that it glows a faint dull red from its own heat; not measured.
Discovery & history
- Method
- Transit detection
- Name
- Designated 'b' under the IAU convention that letters a star's planets 'b', 'c'… in the order found (the star is the unwritten 'a'); no IAU proper name is assigned.
One of the first transiting planets found (2006); NASA's Kepler measured its reflected light at under 1% — the lowest planetary albedo then known.
Images
Images from open archives · credit shown per image