Updates to Pulsator Periods in NGC 3201
Volume 50 number 1 (2022)
- Avni Bansal
- Stanford Online High School, 415 Broadway Academy Hall, Floor 2, 8853, Redwood City, CA 94063; avnibansal2004@gmail.com
- Paul Hamrick
- Stanford Online High School, 415 Broadway Academy Hall, Floor 2, 8853, Redwood City, CA 94063; paulahamrick@gmail.com
- Kalée Tock
- Stanford Online High School, 415 Broadway Academy Hall, Floor 2, 8853, Redwood City, CA 94063; kaleeg@stanford.edu
Abstract
The periods for RR Lyrae variables in NGC 3201 were calculated using the “string length method” in order to update or verify their periods. We confirm the published periods for 54 RR Lyraes in the cluster and offer eight period updates. We also identify the possibility that there is a non-linear CCD brightness response across different telescope cameras of the same specifications, which can result in pseudo-pulsations when multiple telescopes are used to image the cluster. Finally, we observe that in cases where two stars are very close together, source extractor photometry often only discerns one of the stars. Although point spread function photometry is more likely to discern both, it introduces challenges in identifying which star is which. The use of both photometric algorithms in tandem can help to untangle ambiguities.