YY Draconis = 3A1148+719 = PG1140+72 (=DO Dra)

IPs

AE Aqr
FO Aqr
XY Ari
V405 Aur
HT Cam
MU Cam
DW Cnc
BG CMi
V709 Cas
V1025 Cen
TV Col
TX Col
UU Col
V2306 Cyg
YY Dra
PQ Gem
DQ Her
EX Hya
NY Lup
V2400 Oph
GK Per
AO Psc
WX Pyx
V1223 Sgr
V1062 Tau
RX J2133

Candidates

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YY Draconis = 3A1148+719 = PG1140+72 (=DO Dra)

A finding chart for YY Dra

SkyView image of YY Dra (see important notes).

Position:

Equatorial: 11^h43^m38.51^s, +71^d41^m19.2^s (J2000)
Galactic: l=130.31, b=+44.46

Finding Chart:

Patterson et al (1992)

Brightness:

B~15 (quiescence); fx (2-10 keV)~1.4x10^(-11) ergs/cm/cm/s (ASCA)

Periods:

Orbital: 0.164988 d = 3.96 hr = 14255 s (r.v. of the secondary)
HJD = 2446948.60551(11) + 0.164988(23) E
(Mateo et al 1991) for secondary's inferior conjunction.
Spin: ~0.00613d ~ 8.83 min ~530s, not seen strongly in any band.
No good spin ephemeris known?
Others: most X-ray power at 265s (1/2 spin period), 275/550s sidebands in the optical.

Inclination:

42+/-5.

Distance:

155pc.

Discovered as an "Algol" way back when, and given the variable star designation YY Dra; when rediscovered as a PG and X-ray source, new name DO Dra was given. Patterson et al (1992) make a convincing argument that they are one and the same, and hence the original name YY Dra should be used.