About TOI-5398 b
TOI-5398 b is an uncommon exoplanet. It lies about 426.8 light-years from Earth, has an equilibrium temperature near 947 K, spans roughly 10.3 Earth radii and weighs about 58.7 Earth masses.
So low-density it would float on water.
Uncommon exoplanet 31 EP
TOI-5398 b
RA 161.8796° · Dec 36.3294° · exoplanet
Score breakdown
· 5 badgesUncommon 33 pts → Rare
- Puffy low-density world +12
- Multi-planet system +6
- Confirmed exoplanet +5
- Gas giant +4
- Found by TESS +4
Total score 31
2 more points to reach Rare.
Badges
- Confirmed exoplanet · +5
- Gas giant · +4
- Puffy low-density world · +12
- Multi-planet system · +6
- Found by TESS · +4
Trivia
What makes it special
- Cotton-candy planet. So low-density it would float on water.
Could we get there?
- Verdict. Hopelessly far for any craft humanity can build today.
Getting there
- Aboard Voyager 1. ≈ 7.5 million years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 666.4 thousand years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 4268 years in a starship at a tenth of light speed.
- Distance. 427 light-years from Earth.
Look-back time
- Look-back time. The light you'd see left around the year 1599.
Saying hello
- Say hello. A radio message and its reply would take 854 years round-trip.
Standing on it
- A year here. A full year lasts just 10.6 Earth days.
By the numbers
- Size. About 10.3× the width of Earth.
- Volume. About 1093 Earths could fit inside it.
- Mass. Roughly 58.7× Earth's mass — about 0.2 Jupiters.
- Your weight. You'd weigh about 0.6× your Earth weight standing here.
- Density. Less dense than water — drop it in a big enough ocean and it would float.
- Temperature. Around 674°C — hotter than a self-cleaning oven.
How we found it
- Discovery. Found by Transiting Exoplanet Survey Satellite (TESS) using the transit method.
Cosmic context
- Crowded system. One of at least 2 planets orbiting its star.
Properties
- density gcc
- 0.29
- discovery facility
- Transiting Exoplanet Survey Satellite (TESS)
- discovery method
- Transit
- dist ly
- 426.7914
- eccentricity
- 0.13
- eq temp k
- 947
- insolation
- 118.413
- mass earth
- 58.7
- name
- TOI-5398 b
- orbital period days
- 10.5905
- radius earth
- 10.3
- sys num planets
- 2
How to see it
Like any astronomical target, TOI-5398 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 TOI-5398 b is an uncommon exoplanet
TOI-5398 b scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 points would lift it into a rarer tier.
That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Puffy low-density world, Multi-planet system and Found by TESS — 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.