In It For The Long Haul

Ideas more or less related to teaching and learning physics at Luther College.

This morning three of my research students – Dan Herman, Erik Floden and Kevin Honz – left for Chicago to give presentations at the Midstates Consortium for Math and Science Undergraduate Research Symposium. I was impressed with the run through we did a couple days ago and I hope they enjoy the University of Chicago campus.

Dan will be talking about our search for flare-like events in stars. We have been gathering data from the same ~1600 stars since 2003, with well over half a million images acquired in that time. One of the more daunting projects that has grown from this work is sifting through all that data to look for rare, transient events. The work is so challenging because the vast majority, I mean the VAST majority, of apparent transient events are local artifacts related to hot pixels or normalization. Occasionally they are asteroids tumbling by but not the stars getting brighter. We need to find a way to efficiently and accurately discard these artifacts while not losing any potentially interesting astronomical events. I make no claim that we are where we want to be in that work yet but Dan’s presentation will focus on three events that have passed our scrutiny thus far. They are particularly interesting because the light curves (brightness versus time graphs) are symmetric, unlike what one would expect from magnetic field-based flares like those found in UV Ceti stars. Thus, we have been goofing around asking what types of objects might give rise to these light curves if these are gravitational microlensing type events. Shown here is a light curves with data in black and model gravitational microlensing events in blue for one of these events. It is fun, interesting work to do with students 

 Kevin and Erik will present a poster talking about the work they did to recalibrate all our data. I wrote about this work a few months ago. They did a tremendous job of improving our photometric resolution. We had hoped to understand if long-term secular trends in these stars that we were seeing were “real” or again an artifact of calibration.  On that front, their research showed that we have more work to do before we can say anything but they so improved the photometric resolution that we were able to identify 13 new pulsating variable stars to add to the 66 that we had discovered previously. These new variables had lower amplitudes of variation, shorter periods and were fainter on average than the previous 66. Thus, they promise to help us understand the population of these objects much better.

When I last wrote something in this space I talked about what I perceived to be one advantage of teaching astronomy at a liberal arts college – the ability to focus attention on the human thread weaving through the history of our understanding of the universe. The research I describe here is another advantage of living life at a liberal arts college. Not only to I get to do this work with talented array of students who push me on but I haven’t felt pressure to get results immediately and publish frequently. Instead, I have published a little, presented the work a little and let the projects develop slowly so that we could see the subtle things that are just now starting to appear in the data. It’s a slow unfolding that I have been able to share with dozens of students and I am richer for it.

{ Return to Physics Faculty Blog for more posts. }

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