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LibraryS.E. Mullally (STScI), G.C. Sloan (STScI, UNC), J.J. Hermes (Boston Univ.), M. Kunz (STScI, Albert Einstein High School), K. Hambleton (Villanova), R. Bohlin (STScI), S.W. Fleming (STScI), K.D. Gordon (STScI), C. Kaleida (STScI), K. Mohamed (STScI, Amherst Coll.)
2022, AJ, 163, 136
Full manuscript available locally (PDF) or from the arXiv (2201.03670).
We use data from the Transiting Exoplanet Survey Satellite (TESS) to search for, and set limits on, optical to near-infrared photometric variability of the well-vetted candidate James Webb Space Telescope (JWST) spectrophotometric standards. Our search of 37 of these candidate standards has revealed measurable periodic variability in 15 stars. The majority of those show variability that is less than half a percent; however, four stars are observed to vary photometrically, from minimum to maximum flux, by more than 1% (the G dwarf HD 38949 and three fainter A dwarfs). Variability of this size would likely impact the error budget in the spectrophotometric calibration of the science instruments aboard JWST. For the 22 candidate standards with no detected variability, we report upper limits on the observed changes in flux. Despite some systematic noise, all stars brighter than 12th magnitude in the TESS band show a 3σ upper limit on the total change in brightness of less than half a percent on time scales between an hour and multiple weeks, empirically establishing their suitability as spectrophotometric standards. We further discuss the value and limites of high-cadence high-precision photometric monitoring with TESS as a tool to vet the suitability of stars to act as spectroscopic standards.
Last modified 14 April, 2022. © Gregory C. Sloan and others.