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Journal article
Direct measurement of stellar angular diameters by the VERITAS Cherenkov telescopes
Nature astronomy, v 3(6), pp 511-516
01 Jun 2019
Abstract
The angular size of a star is a critical factor in determining its basic properties(1). 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(2), but only when the photometric uncertainty is smaller than the noise added by atmospheric scintillation(3). 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(4). Here we report two occultations of stars observed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS)(5) 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 mas scale. This is a resolution never achieved before with optical measurements and represents an order of magnitude improvement over the equivalent lunar occultation method(6). 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.
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Details
- Title
- Direct measurement of stellar angular diameters by the VERITAS Cherenkov telescopes
- Creators
- W. Benbow - Smithsonian Astrophysical ObservatoryR. Bird - University of California, Los AngelesA. Brill - Columbia UniversityR. Brose - University of PotsdamA. J. Chromey - Iowa State UniversityM. K. Daniel - Smithsonian Astrophysical ObservatoryQ. Feng - Columbia UniversityJ. P. Finley - Purdue University West LafayetteL. Fortson - University of MinnesotaA. Furniss - California State University, East BayG. H. Gillanders - Ollscoil na Gaillimhe – University of GalwayC. Giuri - German Institute for Adult Education – Leibniz Centre for Lifelong LearningO. Gueta - German Institute for Adult Education – Leibniz Centre for Lifelong LearningD. Hanna - McGill UniversityJ. P. Halpern - Columbia UniversityT. Hassan - German Institute for Adult Education – Leibniz Centre for Lifelong LearningJ. Holder - University of DelawareG. Hughes - Center for Astrophysics Harvard & SmithsonianT. B. Humensky - Columbia UniversityA. M. Joyce - Ollscoil na Gaillimhe – University of GalwayP. Kaaret - University of IowaP. Kar - University of UtahN. Kelley-Hoskins - German Institute for Adult Education – Leibniz Centre for Lifelong LearningM. Kertzman - DePauw UniversityD. Kieda - University of UtahM. Krause - German Institute for Adult Education – Leibniz Centre for Lifelong LearningM. J. Lang - Ollscoil na Gaillimhe – University of GalwayT. T. Y. Lin - McGill UniversityG. Maier - German Institute for Adult Education – Leibniz Centre for Lifelong LearningN. Matthews - University of UtahP. Moriarty - Ollscoil na Gaillimhe – University of GalwayR. Mukherjee - Barnard CollegeD. Nieto - Columbia UniversityM. Nievas-Rosillos - DESY, Zeuthen, GermanyS. O'Brien - McGill UniversityR. A. Ong - University of California, Los AngelesN. Park - University of Wisconsin–MadisonA. Petrashyk - Columbia UniversityM. Pohl - German Institute for Adult Education – Leibniz Centre for Lifelong LearningE. Pueschel - German Institute for Adult Education – Leibniz Centre for Lifelong LearningJ. Quinn - University College DublinK. Ragan - McGill UniversityP. T. Reynolds - Munster Technological UniversityG. T. Richards - University of DelawareE. Roache - Center for Astrophysics Harvard & SmithsonianC. Rulten - University of MinnesotaSadeh - DESY, Zeuthen, GermanyM. Santander - University of AlabamaG. H. Sembroski - Purdue University West LafayetteK. Shahinyan - University of MinnesotaSushch - University of PotsdamS. P. Wakely - Fermi National Accelerator LaboratoryR. M. Wells - Iowa State UniversityP. Wilcox - University of IowaA. Wilhelm - German Institute for Adult Education – Leibniz Centre for Lifelong LearningD. A. Williams - University of California, Santa CruzT. J. Williamson - University of Delaware
- Publication Details
- Nature astronomy, v 3(6), pp 511-516
- Publisher
- NATURE PORTFOLIO
- Number of pages
- 6
- Grant note
- US Department of Energy Office of Science; United States Department of Energy (DOE) US National Science Foundation; National Science Foundation (NSF) NSERC in Canada; Natural Sciences and Engineering Research Council of Canada (NSERC) Smithsonian Institution Young Investigators Program of the Helmholtz Association
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000470757700016
- Scopus ID
- 2-s2.0-85064547712
- Other Identifier
- 991021869218804721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Astronomy & Astrophysics