Photometric Study of the near-contact short period Algol system, AK Canis Minoris

Previous abstract Next abstract

Session 10 -- Variable Stars
Display presentation, Monday, June 12, 1995, 9:20am - 6:30pm

[10.01] Photometric Study of the near-contact short period Algol system, AK Canis Minoris

Ronald G. Samec, Richard J. McDermith, Jamison D. Gray, Brian Carrigan (Millikin University)

As a part of our departments new undergraduate research program, we are surveying the eccentric eclipsing binary (EEB) candidates of Hegedus (1988). AK CMi is listed as a system with a displaced secondary. The observations were taken 10 to 15 February 1994, inclusive, at Lowell Obsevatory, Flagstaff, Arizona. A thermoelectrically cooled EMI 6256S ( S-13 cathode) PMT was used in conjunction with the 0.78 m National Undergraduate Research Observatory reflector. Two precision epochs of minimum light were determined from the observations made during primary and secondary eclipses. They are: Min I = 2449396.7032(5) and Min II = 2449395.8546(3). Targeting the last twenty-three years of data, we calculated improved linear and quadratic ephemerides. The quadratic term, -1.0(2)E-10, suggests that AK CMi is undergoing a continuous period decrease. This may be due to magnetic braking arising from the fast rotating solar-type secondary component. There is little evidence from the present light curves that AK CMi has a eccentric orbit. Assymetries near secondary minima possibly induced by an intermittent gas stream may be responsible for the classification of AK CMi as an EEB. The light curve solution reveals that AK CMi is a short period Algol with an A spectral-type primary component and an early K-type secondary. We calculated mass ratio of ~0.5 and a secondary component fillout of ~90% showing that AK CMi is a near contact binary.

Monday program listing