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Delta Persei — Star in Perseus

Magnitude 3.0m Star Perseus (Per) Visible
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1Physical Properties

Magnitude 3.01
Range 2.99 - 3.04
Variable Type GCAS:
Spectral Type B5III giant
Star Color Blue-white (B-V -0.13)
Distance 513 ly

2Position & Identifiers

RA 03h 42m 55.5s
Dec +47° 47' 15.0"
Constellation Perseus (Per)
HR 1122
HIP 17358
HD 22928
SAO 39053
Bayer Delta
Flamsteed 39 Per
Variable ID Del Per
SIMBAD

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Easy Easy Easy
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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7

Size Comparison

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8

Compare Stars

9

Spectral Classification

10

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
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

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15Stellar Notes

Alpha CV? 2.98 - 3.03V, about 1d. Strong variable emission at 1650A, CaII?
Color excess E(B-V) = +0.04.
Per OB3.
C1 neutral carbon continuum shows discontinuities in UV. Lyman alpha observed from COPERNICUS.
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.

Alpha Persei Cluster
Easy
Open cluster
Open Cluster mag 1.2 3.7° Perseus
NGC 1278
Hard+
Elliptical galaxy
Galaxy mag 12.6 7.4° Perseus
Algol
HIP 14576; Beta Persei; 26 Persei
Easy
Eclipsing binary, period 2.9d
Variable Star mag 2.12 9.2° Perseus
Show on Map

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