Upsilon Andromedae
Where is Upsilon Andromedae?
Look south, about 80° up at 01:45 in Andromeda.
- Rises
- Always up
- Highest
- 01:40
- Sets
- Never
- Best after dark
- 01:45 · 80°
Can I see Upsilon Andromedae?
No. The planets of Upsilon Andromedae 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 Upsilon Andromedae is above the horizon all night. It’s highest after dark at 01:45, in the south at 80°.
Why is Upsilon Andromedae interesting?
Upsilon Andromedae has 4 known planets, discovered between 1996 and 2010 by the radial velocity and radial velocity, astrometry methods.
ups And Ab is a giant planet that orbits in under five days: a “hot Jupiter”.
What can you see?
Eyes
Direction onlyAround magnitude 4.1: visible to the naked eye away from bright city lights.
Binoculars
A clear yellow-white star.
Telescope
A single star. The planets themselves can’t be seen with any backyard telescope.
About
Upsilon Andromedae is a yellow-white star about 44 light-years away, a little larger and hotter than the Sun. In 1999 it became the first Sun-like star known to have more than one planet.
It hosts several giant planets, including a hot Jupiter on a four-and-a-half-day orbit. The star also has a faint red dwarf companion far away.
The host star is easy to see with the naked eye from dark or suburban skies.
Measurements with the Hubble Space Telescope showed that two of its planets orbit at a steep angle to each other, unlike the nearly flat Solar System.
The innermost planet is a hot Jupiter, while the outer giants have orbits ranging from months to years.
The faint red-dwarf companion orbits far from the main star.
Several of its planets have official names from a 2015 public naming contest, and the star itself is called Titawin.
Its planets were found from the tiny wobble they cause in the star’s motion.
The Upsilon Andromedae system
| Planet | Mass | Radius | Orbit | From star | Found | Method |
|---|---|---|---|---|---|---|
| ups And Ab | 0.62 M♃ | — | 4.62 days | 0.059 AU | 1996 | Radial Velocity |
| ups And Ac | 9.10 M♃ | — | 240.9 days | 0.861 AU | 1999 | Radial Velocity, Astrometry |
| ups And Ad | 23.58 M♃ | — | 3.5 years | 2.55 AU | 1999 | Radial Velocity, Astrometry |
| ups And Ae | 1.06 M♃ | — | 10.5 years | 5.2456 AU | 2010 | Radial Velocity |
Questions
Can I see Upsilon Andromedae’s planets?
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