About Nembus
Description
Nembus, 51 Andromedae, is a K-type giant of spectral class K3- III CN0.5 about 177 light-years away. It shines at magnitude 3.57 and is one of the brighter naked-eye stars in Andromeda, though its traditional "51" Flamsteed designation preserves no Greek letter. Nembus hosts no confirmed planets and has no close companions.
Observing Tips
Nembus lies in the northwestern part of Andromeda, west of the Great Andromeda Galaxy (M31). In binoculars it appears as a distinct orange-red point. Use Nembus as a starting reference when hunting for M31 — the galaxy lies about 14 degrees to the east. Best observed September through January.
History
The name Nembus comes from a medieval Latin astronomical text and has uncertain etymology. The IAU adopted the name in 2017.
Fun Facts
Nembus is one of several stars that Flamsteed cataloged with a number but that lacked a prior Bayer Greek-letter designation. The star was later assigned to Andromeda in the 20th-century boundary reforms, keeping its Flamsteed number as its primary label.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Medium+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Survey Image
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Explore
7
Size Comparison
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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