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Electra — Star in Taurus

HIP 17499; 17 Tauri

Magnitude 3.7m Star Taurus (Tau) Visible
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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

Magnitude 3.70
Spectral Type B6III giant
Star Color Blue-white (B-V -0.11)
Distance 405 ly

2Position & Identifiers

RA 03h 44m 52.5s
Dec +24° 06' 48.0"
Constellation Taurus (Tau)
HR 1142
HIP 17499
HD 23302
SAO 76131
Flamsteed 17 Tau

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Easy Medium+ Medium+
50mm finder Easy Easy Easy
150mm scope Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Oct – Dec (peak: Nov)

5Survey Image

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Size Comparison

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Spectral Classification

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Hertzsprung-Russell Diagram

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Stellar Lifecycle

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Blackbody Spectrum

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Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

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Stellar Fusion

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15Stellar Notes

Sep. 0.062". Occultation of 1972 Mar. 19 indicated mag. diff 3.4, sep. 0.010".
4.0, 6.0, sep. 0.002", 100.46d, K 26.0k/s, V0 -0.3k/s, asini 30.7. Unresolved by speckle interferometry.
Pleiades cluster; Mel 22 #468; in reflection nebula; Pleiades nebula. Member assoc. Tau R1 at 110 pc.
Electra.
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Light Travel Time Machine

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Relativistic Travel

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