Preempting an ‘oops’ with JWST

A finder chart and TESS light curve of the now-omitted JWST standard star HD 38949 (credit Mullally et al. 2022).

In January 2022, Deputy Project Scientist for JWST Susan Mullally and members of the BUWD group announced the first results of a project to monitor nearly all possible spectrophotometric standards that are planned to calibrate the high-precision observations undertaken by the recently launched 6.5-meter James Webb Space Telescope. Using another NASA mission, TESS, we found that most planned standards are suitable for calibrations. However, we also discovered four that are intrinsically quite variable, including one especially poor standard that the JWST team has now thrown out (see image above). The work by Mullally, Sloan, Hermes et al. 2022 has been accepted for publication in the Astrophysical Journal; a short thread on the discovery can be found here.

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