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Double Double

Lyra Double Double
R.A.E1a is 18h 44m 32.764s
Dec.+39° 37' 0.94"
Mean Radial Velocity-
Magnitude+5 to +6.43
Distance180 Ly
LocationIn Lyra, within Milky Way
Other IDsE1 Lyr,HIP91919,TYC 3122-03438-2
Element 1 and 2 Spectral type F1,F1
Element 3 and 4Main sequence stars ,Spectral type F1 with A8
Orbital Period1165 and 585 years





Double Double

Scope 8" Intes Micro mn-86
Mount EQ6 unguided.
Exposure5 x 0.3 sec for the hx516, 233 out of 459 frames for the webcam
Post-processingStacked in AA3 and registax
FiltersIR
Cameratoucam webcam ( above ) and Starlight Express hx516 ( below )
Location Claines
Date11th July 2005

The four stars are in two pairs separated by 3.5 arcmins, and so they can just about be resolved with the unaided eye. Using a telescope reveals the two pairs, and all the stars in this quadruple system are gravitationally bound to one another. The magnitude of the four stars range from magnitude +5 to +6.43, and the two stars in each pair orbit each other about 2 arc-seconds apart. The entire system is 180 light-years from us and the two pairs are 0.2 light-years apart or 13,000 AU apart . Each member of the pair are themselves separated from the other by 160AU.

The top pair of stars , E1a and E1b are a slow binary system with 1165 year orbit: 5.0, 6.1; PA 350 and separation 2.6", with magnitudes of +5.00 and +6.43. The lower pair of stars , E2c and E2d are about twice as fast, with a period of 585 years: 5.2, 5.5; PA 83.5, separation 2.3", with magnitudes of +5.23 and +5.36.





Double Double