:INFO
Gas giant around HR 8799
It is 1.16 times Jupiter's radius, closest in size to Jupiter, and 3000.0 times Earth's mass. A year there lasts 101.3 years, on an orbit 62.0 times Mercury's distance from the Sun.

:JOURNEY
HR 8799 from the inside out
1 16.400 AU
2 24.000 AU
3 38.000 AU
4 68.000 AU

:STATS
[icon:TARGET] Radius | 13.00 Earth radii
[icon:CHART] Mass | 3000.0 Earth masses
[icon:CLOCK] One year | 101.3 years
[icon:BOLT] Orbit radius | 24.0000 AU
[icon:USERS] Distance | 135 light-years

:TIMELINE
🔭🪐📅
2008-01-01 | HR 8799 b, HR 8799 c, HR 8799 d
2010-01-01 | HR 8799 e

:CHECKLIST
What the archive holds on this planet
[ ] A size. Yes.
[ ] A weight, not just a width. Yes.
[ ] A density, the one clue to composition. No.
[ ] How far out it orbits. Yes.
[ ] A temperature someone observed rather than calculated. No.
[ ] An eccentricity, so the orbit shape is known. No.

:PATH
What a direct image buys you
Where it is, how bright it is, and a spectrum taken from the planet directly.

:NOTE
HR 8799 has 4 known planets. A crowded system is worth more than the sum of its planets: the timing of each transit constrains the others.

:NOTE
This is one of the rare planets that has actually been photographed. Fewer than a hundred of the thousands known were found this way, and they are mostly young giants far from their stars.

:NOTE
Found by W. M. Keck Observatory in 2008.

:THREAD

:LINK
https://exoplanetarchive.ipac.caltech.edu/overview/HR%208799%20d
NASA Exoplanet Archive: source data, including the values not used here