Monthly Archives: July 2012

CCD error

The camera is hung in a state that requires a power cycling.
Camera fails to execute a software reset
The camera returns the error “failure in reset”
The leach controller window shows highly incorrect values in gain (e.g., -4095), amp, heat, etc.
Cycle the power on the camera on site (cannot be done remotely). It is unclear where this problem stems from.

Updated RCT blog

I’ve updated the RCT webpage to highlight science. I’ve moved the telescope maintenance issues and bugs to a separate location on the site, but you will still get posts will still get to the RSS. Please review and let me know if have suggestions or comments.

Villanova’s Living with a Red Dwarf Program

Because of their slow nuclear fusion rates, dM stars undergo almost negligible changes in temperature or luminosity over time, making traditional age determination methods (such as isochronal fits) essentially impossible.

There is, however, one property of dM stars that does noticeably change over time – the strength of their magnetic fields. As dM stars (along with K- and solar-type G-stars) age, they undergo the “spin-down” effect, where the rotation period lengthens over time. This is a quantity that can be directly measured and then calibrated as a “dating method” or “aging method.” The problem has been the need to calibrate a relationship between stars of known rotation periods and stars of known ages. The database of dM stars with reliably known ages has long been limited but, recently, two separate studies published by Garces et al. and Zhao et al. in 2011 furnished a nice list of dM stars with white dwarf companions. Recent work has allowed for much more reliable white dwarf ages to be determined, and that age can be assigned to the companion dM star through association. We’ve been observing as many of these guys as we can with the RCT. I’m attaching a couple lightcurves we’ve obtained so far and also our Rotation over Time graphs, where the red points show rotation rates derived from RCT photometry. The results of the program so far have been pretty exciting.