The K2 M67 Study: Establishing the Limits of Stellar Rotation Period Measurements in M67 with K2 Campaign 5 Data
| Autor: | Søren Meibom, Rebecca Esselstein, Suzanne Aigrain, Jennifer L. van Saders, Andrew Vanderburg, Robert D. Mathieu, Jeffrey C. Smith |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Physics
010308 nuclear & particles physics Stellar rotation FOS: Physical sciences Astronomy and Astrophysics Light curve Rotation Geodesy 01 natural sciences Stars Amplitude Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science 0103 physical sciences Range (statistics) 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Main sequence Open cluster |
| Popis: | The open cluster M67 offers the unique opportunity to measure rotation periods for solar-age stars across a range of masses, potentially filling a critical gap in the understanding of angular momentum loss in older main sequence stars. The observation of M67 by NASA K2 Campaign 5 provided light curves with high enough precision to make this task possible, albeit challenging, as the pointing instability, 75d observation window, crowded field, and typically low-amplitude signals mean determining accurate rotation periods on the order of 25 - 30d is inherently difficult. Lingering, non-astrophysical signals with power at >25d found in a set of Campaign 5 A and F stars compounds the problem. To achieve a quantitative understanding of the best-case scenario limits for reliable period detection imposed by these inconveniences, we embarked on a comprehensive set of injection tests, injecting 120,000 sinusoidal signals with periods ranging from 5 to 35d and amplitudes from 0.05% to 3.0% into real Campaign 5 M67 light curves processed using two different pipelines. We attempted to recover the signals using a normalized version of the Lomb-Scargle periodogram and setting a detection threshold. We find that while the reliability of detected periods is high, the completeness (sensitivity) drops rapidly with increasing period and decreasing amplitude, maxing at 15% recovery rate for the solar case (i.e. 25d period, 0.1% amplitude). This study highlights the need for caution in determining M67 rotation periods from Campaign 5 data, but this can be extended to other clusters observed by K2 and, soon, TESS. 55 pages, 22 figures, published by ApJ |
| Databáze: | OpenAIRE |
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