RT Journal Article
T1 Direct measurement of stellar angular diameters by the VERITAS Cherenkov telescopes
A1 Benbow, Wystan
A1 Nieto Castaño, Daniel
A1 Williamson, Terrence
AB The angular size of a star is a critical factor in determining its basic properties. Direct measurement of stellar angular diameters is difficult: at interstellar distances stars are generally too small to resolve by any individual imaging telescope. This fundamental limitation can be overcome by studying the diffraction pattern in the shadow cast when an asteroid occults a star, but only when the photometric uncertainty is smaller than the noise added by atmospheric scintillation. Atmospheric Cherenkov telescopes used for particle astrophysics observations have not generally been exploited for optical astronomy due to the modest optical quality of the mirror surface. However, their large mirror area makes them well suited for such high-time-resolution precision photometry measurements. Here we report two occultations of stars observed by the VERITAS Cherenkov telescopes with millisecond sampling, from which we are able to provide a direct measurement of the occulted stars’ angular diameter at the _ 0:1 milliarcsecond scale. This is a resolution never achieved before with optical measurements and represents an order of magnitude improvement over the equivalent lunar occultation method. We compare the resulting stellar radius with empirically derived estimates from temperature and brightness measurements, confirming the latter can be biased for stars with ambiguous stellar classifications.
PB Nature Portfolio
SN 2397-3366
YR 2023
FD 2023
LK https://hdl.handle.net/20.500.14352/88514
UL https://hdl.handle.net/20.500.14352/88514
LA eng
NO Benbow, W., Bird, R., Brill, A. et al. Direct measurement of stellar angular diameters by the VERITAS Cherenkov telescopes. Nat Astron 3, 511–516 (2019). https://doi.org/10.1038/s41550-019-0741-z
NO Artículo firmado por más de 10 autores.
NO United States Department of Energy
NO National Science Foundation (United States)
NO Smithsonian Institution
NO Natural Sciences and Engineering Research Council of Canada
NO Helmholtz Association
DS Docta Complutense
RD 7 abr 2025