About HD 102117 b
HD 102117 b is a trash exoplanet. It lies about 129.1 light-years from Earth, has an equilibrium temperature near 781 K, spans roughly 8.47 Earth radii and weighs about 54.03 Earth masses.
About 8.5× the width of Earth.
Trash exoplanet 9 EP
HD 102117 b
RA 176.2097° · Dec -58.7040° · exoplanet
Score breakdown
· 2 badgesTrash 15 pts → Common
- Confirmed exoplanet +5
- Gas giant +4
Total score 9
6 more points to reach Common.
Badges
- Confirmed exoplanet · +5
- Gas giant · +4
Trivia
Could we get there?
- Verdict. Hopelessly far for any craft humanity can build today.
Getting there
- Aboard Voyager 1. ≈ 2.3 million years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 201.6 thousand years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 1291 years in a starship at a tenth of light speed.
- Distance. 129 light-years from Earth.
Look-back time
- Look-back time. The light you'd see left around the year 1897.
Saying hello
- Say hello. A radio message and its reply would take 258 years round-trip.
Standing on it
- A year here. A full year lasts just 20.8 Earth days.
By the numbers
- Size. About 8.5× the width of Earth.
- Volume. About 608 Earths could fit inside it.
- Mass. Roughly 54× Earth's mass — about 0.2 Jupiters.
- Your weight. You'd weigh about 0.8× your Earth weight standing here.
- Density. Less dense than water — drop it in a big enough ocean and it would float.
- Temperature. Around 508°C — hotter than a self-cleaning oven.
How we found it
- Discovery. Found by La Silla Observatory using the radial velocity method.
Properties
- density gcc
- 0.489
- discovery facility
- La Silla Observatory
- discovery method
- Radial Velocity
- dist ly
- 129.0899
- eccentricity
- 0.12
- eq temp k
- 780.86
- insolation
- 63.8539
- mass earth
- 54.0311
- name
- HD 102117 b
- orbital period days
- 20.8133
- radius earth
- 8.47
- sys num planets
- 1
How to see it
Like any astronomical target, HD 102117 b is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.
Why HD 102117 b is a trash exoplanet
HD 102117 b scores 9 points on Spacedle's rarity scale, which places it in the trash tier. Another 6 points would lift it into a rarer tier.
That score comes from 2 science badges — Confirmed exoplanet and Gas giant — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.