:INFO
Gas giant around HR 8799
It is 1.16 times Jupiter's radius, closest in size to Jupiter, and 2000.0 times Earth's mass. A year there lasts 465.4 years, on an orbit 175.7 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 | 2000.0 Earth masses
[icon:CLOCK] One year | 465.4 years
[icon:BOLT] Orbit radius | 68.0000 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 measured mass. Yes.
[ ] A density, which decides rock or gas. No.
[ ] An orbital distance. Yes.
[ ] A measured temperature rather than a derived one. No.
[ ] An eccentricity, so we know if the orbit is a circle. No.

:PATH
What a direct image buys you
A position, a brightness, and light that can be split into a spectrum.

: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
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
Found by Gemini Observatory in 2008.

:THREAD

:LINK
https://exoplanetarchive.ipac.caltech.edu/overview/HR%208799%20b
NASA Exoplanet Archive: every published measurement of this planet