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4 years ago in Astronomy , Time-Domain Astronomy By Rafael

What is the best technique to detect variability in stars?

I'm starting a time-domain astronomy project and need to set up a reliable pipeline from raw images to confirmed variable stars. I understand the basic principle of differential photometry, but I'm unsure about the optimal statistical tests for detection, how to distinguish true periods from aliases, and the best practices for confirming a signal is astrophysical and not instrumental.

 

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By Karan D Answered 3 years ago

The gold standard is a pipeline combining careful differential photometry with a suite of statistical tests. I always start by using a proven software like IRAF or AstroImageJ to perform aperture photometry relative to several stable comparison stars. Then, I run the light curve through a Lomb-Scargle periodogram to search for periods, but I don't stop there. I visually inspect the phase-folded curve and use statistical tests like the Stetson J-index to assess significance against red noise. Crucially, I have learned you must verify the signal is on the target by checking for similar patterns in your comparison stars or guide camera logs to rule out tracking or focus issues.

 

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