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EE CEPHEI

EE Cephei (Cep)

EE Cep is an eclipsing binary whose nature still remains unclear. The various features observed during the different eclipses and the lack of any evidence for a star-like secondary are in favour with the hypothesis that the secondary contains a dark, opaque disc covering a central low-luminosity star or binary system.

The most promising model remains that of a dark, precessing disk around a low luminosity central object (Mikolajewski & Graczyk 1999, Graczyk et al. 2003). The precession changes both the inclination of the disc to the line of sight, and the tilt of its cross-section to the transit direction. The unique shape of the eclipse observed in 1969 can be explained by a practically edge-on and non-tilted projection of the disc. Two hypotheses can be considered for such a disc: (i) it has a proto-planetary origin; (ii) it is a post-planetary object (a result of planetary disintegration). An important question is the nature of the central body embedded in the disk. It can be a low massive single star or a close binary system. The only similar object previously known with a dark circumstellar disc is epsilon Aur - the longest period (~27 years) eclipsing binary.


Comparison Stars

EE CEPHEI DATA

EE Cephei = HR = HD
Name: ?

R.A. (2000) 22h 09m 22.771s
DEC. (2000) +55d 45' 24.76"
COMP
A
B
SPECT.
B5III-IV+e
B8 Ve
DIAM
?
MASS
?
?
LUM.
?
?
ABS.
?
?
MAG
?
?
TEMP.
?
?
I
xx
 
V - I
+3.04
R
xx
 
R - I
+1.40
V
10.72/12.15
 
B - V
+1.77
B
xx
 
U - B
+0.39
U
xx
     

Distance: ? light years

Epoch: JD 2,434,346.0

Period: 2049.53 days/ 5.6 years

Secondary Eclipse at Phase: ?

Ingress/Egress: ? days
Totality: ?
Length: 17 days

Next Eclipse: 2,454,891.30
9 January 2009

Secondary Eclipse - ?

Maximum Separation Date - ?


References

IBVS 965

IBVS 1225

IBVS 1939

IBVS 5412

Timing of 1999 Eclipse (pdf 116 K)

EE Cep 2003 (pdf 160 K)

Star
U
B
V
R
I
a = BD+55°2690 10.86 10.68 10.38 10.09 9.87
b = GSC39732150 11.31 11.47 11.23 10.99 10.81
c = BD+55°2691 11.59 11.47 11.22 10.96 10.75

EE Cephei Fall 2006
Hopkins Phoenix Observatory

12" LX 200 GPS @ f/3.3 and B filter, 30 Second


Page Created 24 July 2005
Modified 12 April 2007

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