Journal article
Direct measurement of stellar angular diameters by the VERITAS Cherenkov Telescopes
Nature Astronomy, Vol.3(6), pp.511-516
04/12/2019
DOI: 10.1038/s41550-019-0741-z
Abstract
The angular size of a star is a critical factor in determining its basic properties1. 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 star2, but only when the photometric uncertainty is smaller than the noise added by atmospheric scintillation3. 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 measurements4. 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 method6. 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.
Details
- Title: Subtitle
- Direct measurement of stellar angular diameters by the VERITAS Cherenkov Telescopes
- Creators
- W Benbow - Smithsonian InstitutionR Bird - University of California, Los AngelesA Brill - Columbia UniversityR Brose - University of PotsdamA. J Chromey - Iowa State UniversityM. K Daniel - Smithsonian InstitutionQ 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 GiuriO GuetaD Hanna - McGill UniversityJ Halpern - Columbia UniversityT HassanJ Holder - University of DelawareG Hughes - Smithsonian InstitutionT. B Humensky - Columbia UniversityA. M Joyce - Ollscoil na Gaillimhe – University of GalwayP Kaaret - University of IowaP Kar - University of UtahN Kelley-HoskinsM Kertzman - DePauw UniversityD Kieda - University of UtahM KrauseM. J Lang - Ollscoil na Gaillimhe – University of GalwayT. T. Y Lin - McGill UniversityG MaierN Matthews - University of UtahP Moriarty - Ollscoil na Gaillimhe – University of GalwayR Mukherjee - Columbia UniversityD Nieto - Columbia UniversityM Nievas-RosilloS O'BrienR. A Ong - University of California, Los AngelesN Park - University of Wisconsin–MadisonA Petrashyk - Columbia UniversityM Pohl - University of PotsdamE PueschelJ Quinn - University College DublinK Ragan - McGill UniversityP. T Reynolds - Cork Institute of TechnologyG. T Richards - University of DelawareE Roache - Smithsonian InstitutionC Rulten - University of MinnesotaI SadehM Santander - University of AlabamaG. H Sembroski - Purdue University West LafayetteK Shahinyan - University of MinnesotaI Sushch - University of PotsdamS. P Wakely - University of ChicagoR. M Wells - Iowa State UniversityP Wilcox - University of IowaA Wilhelm - University of PotsdamD. A Williams - Santa Cruz Institute for Particle PhysicsT. J Williamson - University of Delaware
- Resource Type
- Journal article
- Publication Details
- Nature Astronomy, Vol.3(6), pp.511-516
- DOI
- 10.1038/s41550-019-0741-z
- ISSN
- 2397-3366
- eISSN
- 2397-3366
- Language
- English
- Date published
- 04/12/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199714202771
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