About Electra
Description
Electra, 17 Tauri, is a B6 III blue giant about 405 light-years away, another prominent member of the Pleiades. At magnitude 3.70 it is the third-brightest Pleiad. Electra is a fast-rotating Be-type candidate star, with spectra occasionally showing weak emission lines from a circumstellar gas disk. Its mass is about 5 solar masses.
Observing Tips
Electra forms the western edge of the Pleiades pattern. In binoculars it is one of the six-to-seven naked-eye-visible cluster members. A 4-inch telescope at low power places Electra in a field full of surrounding fainter cluster members — a classic wide-field view of M45. Best observed October through March.
History
Electra is named for another of the seven Pleiades of Greek myth — mother of Dardanus, the legendary founder of Troy. Her name means "shining amber." According to Aratus, Electra withdrew from the cluster in grief after the fall of Troy, supposedly accounting for the sometimes-reported difficulty of seeing all seven sisters with the naked eye.
Fun Facts
Electra's emission-line spectrum fluctuates on timescales of years — the disk occasionally forms and dissipates. Electra is sometimes listed as one of the "missing" Seven Sisters, though astronomical reality is that all seven are visible in moderately dark skies.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Medium+ | 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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