:INFO
Ice giant around Kepler-51
It is 7.10 times Earth's radius, closest in size to Saturn, and 2.1 times Earth's mass, at 0.03 g/cm3, less dense than Earth. A year there lasts 45.15 days, on an orbit 2 times closer to its star than Mercury is to the Sun. Its equilibrium temperature is 543 K, hotter than any desert. The host star Kepler-51 runs at 6018 K with 1.04 times the Sun's mass.

:JOURNEY
Kepler-51 from the inside out
1 0.251 AU
2 0.384 AU
3 0.509 AU

:STATS
[icon:TARGET] Radius | 7.10 Earth radii
[icon:CHART] Mass | 2.1 Earth masses
[icon:FIRE] Equilibrium temperature | 543 K (measured)
[icon:CLOCK] One year | 45.15 days
[icon:BOLT] Orbit radius | 0.2514 AU
[icon:STAR] Host star | Kepler-51 at 6018 K
[icon:USERS] Distance | 2557 light-years
[icon:TRENDING_DOWN] Starlight blocked | 0.478% at each transit

:COUNTER
0.03 g/cm3: less dense than cork

:TIMELINE
🔭🪐📅
2012-01-01 | Kepler-51 b, Kepler-51 c
2014-01-01 | Kepler-51 d

:PATH
What the dip tells you
The depth of the dip is the ratio of the two discs, so the radius follows.

:NOTE
Found by Kepler in 2012. Kepler stared at one patch of sky for four years, which is why so many of its planets have short periods: a planet only counts once you have seen it cross several times.

:NOTE
Kepler-51 has 4 known planets. Systems like this are the ones where architecture can be studied instead of guessed at.

:NOTE
Size from the shadow, mass from elsewhere. Most transiting planets never get the second half, and without it composition stays a guess.

:LINK
https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-51%20b
NASA Exoplanet Archive: every published measurement of this planet