Which planet has the biggest sun in its sky?

The biggest sun in any known sky belongs to TOI-2431 b, where the star spans about 96.3 times the width of the Sun seen from Earth and fills a large part of the daytime sky. Everything about TOI-2431 b

Biggest sun in the sky
TOI-2431 b
96.3× our Sun · 1790°C (3254°F)
The top 25
#WorldApparent sun sizeEquilibrium temp
★ 1TOI-2431 b96.3× our Sun1790°C (3254°F)
2TOI-2260 b91.0× our Sun2336°C (4237°F)
3TOI-2109 b89.3× our Sun3373°C (6103°F)
4Kepler-1340 b88.0× our Sun1901°C (3454°F)
5K2-141 b86.2× our Sun1830°C (3326°F)
6KOI-1843.0385.2× our Sun1381°C (2518°F)
7K2-157 b84.7× our Sun2159°C (3918°F)
8Kepler-990 c83.2× our Sun2113°C (3835°F)
9Kepler-91 b82.0× our Sun1767°C (3212°F)
10Kepler-78 b79.2× our Sun1950°C (3542°F)
11K2-131 b77.6× our Sun1950°C (3542°F)
12TOI-561 b75.9× our Sun2046°C (3715°F)
13K2-223 b75.5× our Sun1998°C (3628°F)
14TOI-1444 b75.3× our Sun1857°C (3374°F)
15Kepler-1547 b72.9× our Sun2913°C (5275°F)
16EPIC 220674823 b72.2× our Sun2051°C (3724°F)
17Kepler-1323 b70.6× our Sun2018°C (3664°F)
18HD 80653 b69.8× our Sun2165°C (3929°F)
19WASP-103 b69.8× our Sun2235°C (4055°F)
20TOI-1798.0269.7× our Sun1663°C (3025°F)
21WASP-12 b69.7× our Sun2328°C (4222°F)
22KELT-9 b69.3× our Sun3648°C (6598°F)
23Kepler-1368 b68.2× our Sun1812°C (3293°F)
24WASP-78 b68.1× our Sun2197°C (3986°F)
25WASP-47 e66.9× our Sun1719°C (3126°F)

Showing the top 25 of 5,571 that qualify.

How we know

This is a geometry problem, not a brightness one: the angle a star covers in the sky follows from its radius and the planet's orbital distance, both of which are catalogued. From Earth the Sun spans about half a degree, roughly the width of a pencil eraser held at arm's length. Multiply that by the figures in this table and the star stops being a disc you can cover with a thumb and becomes a wall of light.

Every world near the top of this ranking orbits its star in hours or a couple of days, which is why the temperature column reads the way it does. These are not places with pleasant enormous sunsets: the same closeness that makes the star huge makes the surface molten.

Common questions

Which planet has the biggest sun in its sky?

The biggest sun in any known sky belongs to TOI-2431 b, where the star spans about 96.3 times the width of the Sun seen from Earth and fills a large part of the daytime sky.

How big does the Sun look from Earth?

About half a degree across, which is close enough to the Moon's apparent size that a total eclipse works at all. Every figure in this table is a multiple of that half-degree disc.

How big would the sun look from the record holder?

About 96.3 times as wide as the Sun looks from Earth on TOI-2431 b, covering a substantial fraction of the sky rather than a small disc in it.

Where does the sun look biggest in our own solar system?

From Mercury, where the Sun spans roughly two to three times the width it does from Earth, depending on where Mercury is on its eccentric orbit. Every world on this table beats that many times over.

Keep exploring: all records · the worst places to visit · the shortest year known