ﻻ يوجد ملخص باللغة العربية
Long term optical monitoring of the dwarf nova OQ Car has been conducted to study the previously unknown behaviour of this star system. The observations have shown OQ Car to have frequent dwarf nova outbursts and revealed the first recorded standstill of this star system. Based on this, we conclude that OQ Car is a new member of the Z Cam type dwarf novae.
The defining characteristic of Z Cam stars are standstills in their light curves. Some Z Cams exhibit atypical behaviour by going into outburst from a standstill. It has previously been suggested that UY Pup had been a Z Cam star, but it was ruled ou
Photometry of Leo5 = 1H 1025+220 show that it is a dwarf nova of the Z Cam subtype. Two long standstills have been observed in the last five years.
I found that V507 Cyg, IM Eri and FY Vul are Z Cam-type dwarf novae and they showed sequences of standstill terminated by brightening, in contrast to fading in ordinary Z Cam stars, followed by damping oscillation. These sequences are characteristic
Combining with our newest CCD times of light minimum of EM Cygni, all 45 available times of light minimum including 7 data with large scatters are compiled and the updated O-C analysis is made. The bestfit for the O-C diagram of EM Cygni is a quadrat
New eclipse timings of the Z Cam-type dwarf nova AY Psc were measured and the orbital ephemeris was revised. Based on the long-term AAVSO data, moreover, the outburst behaviors were also explored. Our analysis suggests that the normal outbursts are q