Is this project an undergraduate, graduate, or faculty project?

Undergraduate

group

What campus are you from?

Daytona Beach

Authors' Class Standing

Jackson L. Sackrider, Sophomore; Katelyn R. Sonnen, Sophomore; Jason P. Aufdenberg, Professor

Lead Presenter's Name

Jackson L. Sackrider

Faculty Mentor Name

Jason P. Aufdenberg

Abstract

Angular diameter measurements by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) Stellar Intensity Interferometer (SII) in a waveband near 400 nm complement existing angular diameter measurements in the near-infrared. VSII observations will test fundamental predictions of stellar atmosphere models and should be more sensitive to limb darkening and gravity darkening effects than measurements in the near-IR, however, the magnitude of this difference has not been systematically explored in the literature. In order to investigate the synthetic interferometric (as well as spectroscopic) appearance of stars in the blue relative to the near-IR, we have computed grids of model atmospheres appropriate for six stars observed by VSII: four rapid rotators α Cep, α Leo, α Lyr, and η UMa, along with two slow rotators β UMa and β CMa. We predict these stars will appear smaller in angular size and exhibit higher visibilities in the first lobe of the visibility curve at 400 nm relative to 1746 nm at the same spatial frequencies, consistent with our expectations. This poster focuses on two of these stars, β UMa and α Leo. Synthetic spectra match archival spectra around 400nm best for β UMa and α Leo. We will compare our interferometric predictions for the nearly spherical, slow rotator, β UMa, and the highly distorted, rapid rotator, α Leo.

Did this research project receive funding support from the Office of Undergraduate Research.

Yes, SURF

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Spinning Slow and Fast: Stellar Atmosphere Models for β Ursae Majoris and α Leonis.

Angular diameter measurements by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) Stellar Intensity Interferometer (SII) in a waveband near 400 nm complement existing angular diameter measurements in the near-infrared. VSII observations will test fundamental predictions of stellar atmosphere models and should be more sensitive to limb darkening and gravity darkening effects than measurements in the near-IR, however, the magnitude of this difference has not been systematically explored in the literature. In order to investigate the synthetic interferometric (as well as spectroscopic) appearance of stars in the blue relative to the near-IR, we have computed grids of model atmospheres appropriate for six stars observed by VSII: four rapid rotators α Cep, α Leo, α Lyr, and η UMa, along with two slow rotators β UMa and β CMa. We predict these stars will appear smaller in angular size and exhibit higher visibilities in the first lobe of the visibility curve at 400 nm relative to 1746 nm at the same spatial frequencies, consistent with our expectations. This poster focuses on two of these stars, β UMa and α Leo. Synthetic spectra match archival spectra around 400nm best for β UMa and α Leo. We will compare our interferometric predictions for the nearly spherical, slow rotator, β UMa, and the highly distorted, rapid rotator, α Leo.

 

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