LHS 1140
Where is LHS 1140?
Look south, about 23° up at 00:49 in Cetus.
- Rises
- 20:04
- Highest
- 00:48
- Sets
- 05:31
- Best after dark
- 00:49 · 23°
Can I see LHS 1140?
No. The planets of LHS 1140 can’t be seen with the eye, binoculars or any amateur telescope: they are lost in their star’s light. What you can do is point toward the star.
From London tonight, the star LHS 1140 is above the horizon after dark. It’s highest after dark at 00:49, in the south at 23°.
Why is LHS 1140 interesting?
LHS 1140 has 2 known planets, discovered between 2017 and 2018 by the primary transit method.
One of them is close to Earth’s size or mass, based on the catalog values.
What can you see?
Eyes
Direction onlyNot visible.
Binoculars
Not visible.
Telescope
The star is around magnitude 14 and needs a large amateur telescope and a detailed chart. The planets themselves can’t be seen with any backyard telescope.
About
LHS 1140 is a quiet red dwarf about 41 light-years away in Cetus. Its planet LHS 1140 b is a super-Earth, larger and heavier than our planet, orbiting in the habitable zone every 25 days.
Because it passes in front of its star and is relatively close, it is one of the best targets for studying a potentially habitable world. Early James Webb Space Telescope observations hint that it may have an atmosphere, but the results are tentative.
LHS 1140 b is about 1.7 times Earth’s width and several times its mass. Its density suggests it may contain a large fraction of water, which could make it an ocean world or a frozen snowball.
Its star has only about a fifth of the Sun’s mass, and a second, inner planet, LHS 1140 c, orbits closer and is too hot for liquid water.
The planets were found by watching the star dim slightly as they passed in front of it.
The LHS 1140 system
| Planet | Mass | Radius | Orbit | From star | Found | Method |
|---|---|---|---|---|---|---|
| LHS 1140 c | 1.81 M⊕ | 1.28 R⊕ | 3.78 days | 0.0268 AU | 2018 | Primary Transit |
| LHS 1140 b | 6.99 M⊕ | 1.73 R⊕ | 24.7 days | 0.0936 AU | 2017 | Primary Transit |
Questions
Could LHS 1140 b have water?
Sources: The Extrasolar Planets Encyclopaedia (CC BY 4.0); star chart: Wikidata (CC0). Positions computed for your place and time with astronomy-engine. Data & Licences