Rare exoplanet 43 EP

HAT-P-9 b

RA 110.1685° · Dec 37.1406° · exoplanet

Loading sky survey…

🌌 View in 3D star map

Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 5 badges

43 pts · Rare

Rare 46 pts → Epic

Lava world +14
Hot Jupiter +10
Distant (>1000 ly) +10
Confirmed exoplanet +5
Gas giant +4

Total score 43

3 more points to reach Epic.

Badges

Confirmed exoplanet · +5
Gas giant · +4
Hot Jupiter · +10
Lava world · +14
Distant (>1000 ly) · +10

Trivia

What makes it special

Lava world. Its surface is likely an ocean of molten rock.

Could we get there?

Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

Aboard Voyager 1. ≈ 26.1 million years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 2.3 million years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 14.8 thousand years in a starship at a tenth of light speed.
Distance. 1485 light-years from Earth.

Look-back time

Look-back time. The light you'd see left around the year 541.

Saying hello

Say hello. A radio message and its reply would take 2969 years round-trip.

Standing on it

A year here. A full year lasts just 3.9 Earth days.

By the numbers

Size. About 15.6× the width of Earth.
Volume. About 3807 Earths could fit inside it.
Mass. Roughly 238× Earth's mass — about 0.7 Jupiters.
Your weight. You'd weigh about 1.0× your Earth weight standing here.
Density. Less dense than water — drop it in a big enough ocean and it would float.
Temperature. Around 1267°C — hotter than a self-cleaning oven.

How we found it

Discovery. Found by HATNet using the transit method.

Properties

density gcc: 0.342
discovery facility: HATNet
discovery method: Transit
dist ly: 1484.6719
eccentricity: 0.084
eq temp k: 1540
insolation: 931
mass earth: 238.0547
name: HAT-P-9 b
orbital period days: 3.9228
radius earth: 15.6141
sys num planets: 1

About HAT-P-9 b

HAT-P-9 b is a rare exoplanet. It lies about 1,484.7 light-years from Earth, has an equilibrium temperature near 1,540 K, spans roughly 15.61 Earth radii and weighs about 238.05 Earth masses.

Its surface is likely an ocean of molten rock.

How to see it

Like any astronomical target, HAT-P-9 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 HAT-P-9 b is a rare exoplanet

HAT-P-9 b scores 43 points on Spacedle's rarity scale, which places it in the rare tier. Another 3 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Hot Jupiter, Lava world and Distant (>1000 ly) — 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.