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31 Cyg

HIP 99675; 31 Cyg Star Cygnus (Cyg) Visible Level 1 Naked eye / Binoculars
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Physical Properties

Magnitude 3.79
Range 3.73 - 3.89
Period 3784 days
Variable Type Eclipsing Binary (Algol-type)
Spectral Type K2II+...
Star Color Red (B-V 1.28)
Distance 871 ly

Position & Identifiers

RA 20h 13m 37.9s
Dec +46° 44' 29.0"
Constellation Cygnus (Cyg)
HR 7735
HIP 99675
Flamsteed 31 Cyg
Variable ID V695 Cyg
Double Cat 13554

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Stellar Notes

ADS 13554A, EA 3.77 - 3.88V, 3784.3d. Amp. varies strongly with wavelength. C = NSV 12931, 6.98V.
Component C, 6.99V, -0.14(B-V), -0.58(U-B) B5V, vsini : 25k/s, at 107" fixed. AP probably single star.
ADS 13554A, 3784.3d, K 14.0k/s, V0 -7.7k/s, msin3i 9.19, asini 711. Unresolved by speckle interferometry. SKYLAB | indicates cool star with hot companion. vsini of secondary 80k/s.
Also classified K4Iab + B4IV-V.
See HR 7730.

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