VV Cephei — Star in Cepheus
Observe
1Physical Properties
Magnitude
4.91
Range
4.73 - 5.55
Period
7430 days
Variable Type
Eclipsing Binary (Algol-type)
Spectral Type
M2Iaep+B8Ve
Star Color
Red
(B-V 1.77)
Distance
815 ly
2Position & Identifiers
RA
21h 56m 39.1s
Dec
+63° 37' 32.0"
Constellation
Cepheus
(Cep)
HR
8383
HIP
108317
HD
208816
SAO
19753
Variable ID
VV Cep
Querying VizieR catalog...
3How easy to spot?
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Medium+ | Medium | Hard+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
Best season
Jul – Sep
(peak: Aug)
5Survey Image
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Explore
6
Size Comparison
Querying VizieR for stellar data…
7
Compare Stars
8
Spectral Classification
9
Hertzsprung-Russell Diagram
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10
Stellar Lifecycle
11
Blackbody Spectrum
12
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
13
Stellar Fusion
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14Stellar Notes
EA 4.80 - 5.36V, 6.65 - 7.46p, 7430d. Also slow oscillations, amp. 0.15, per. 13.7y and amp. 0.03, per. 349d. Red | observations indicate Sr amp. 0.4m, 58d. H alpha varies in 118.37d, period stable over 20y interval. This is probably | the pulsation period of the red component. Amplitude varies in period 825d or more. The blue companion may be | intrinsically variable. VV Cep also magnetic variable.
A* var. M2Iab, B6IIe. Combined mag., colors. Absolute magnitudes based on astrometric and spectroscopic data are | -4.0V for red component, -2.3 for the blue.
7430.5d, K 19.4k/s, V0 -20.2k/s, msin3i 18.0, asini 1860. The SB secondary is probably also the visual | companion. Mass transfer from red star to the hot companion. SB unresolved by speckle interferometry at 4-meter Mayall | telescope in 1975-6.
Cep OB2.
Companion variously classified B9, B8Ve, and B6II.
15
Light Travel Time Machine
16
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.
NGC 7160
Rich open cluster
Open Cluster
mag 6.1
1.1°
Cepheus
Kurhah
HIP 108917; Xi Cephei; 17 Cephei
Easy double, sep 8.2″
Double Star
mag 4.29
1.3°
Cepheus
19 Cep
Hot blue O-type star
Star
mag 5.11
1.7°
Cepheus
Delta Cep
Pulsating variable, period 5.4d
Variable Star
mag 3.75
6.5°
Cepheus
Sh2-155
C9
Emission nebula — try an OIII filter
Emission Nebula
mag 7.7
7.0°
Cepheus
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