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Research Spending & Results

Award Detail

Doing Business As Name:East Tennessee State University
  • Richard Ignace
  • (423) 439-6904
Award Date:07/10/2020
Estimated Total Award Amount: $ 302,768
Funds Obligated to Date: $ 302,768
  • FY 2020=$302,768
Start Date:08/01/2020
End Date:07/31/2022
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.049
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Lifting the veil on Wolf-Rayet rotation using wind structure: Multi-wavelength and Spectropolarimetric Approaches
Federal Award ID Number:2009412
DUNS ID:051125037
Parent DUNS ID:878135631
Program Officer:
  • Sarah Higdon
  • (703) 292-2541

Awardee Location

Street:P O Box 70565
City:Johnson City
County:Johnson City
Awardee Cong. District:01

Primary Place of Performance

Organization Name:East Tennessee State University
Street:P O Box 70565
City:Johnson City
County:Johnson City
Cong. District:01

Abstract at Time of Award

When a Wolf-Rayet (WR) star goes supernova, its core collapses to form either a black hole or a neutron star. The outcome depends on how fast the WR star was spinning, but this is difficult to measure for WR stars, which are shrouded by their own wind. However, distortions in the wind can form corotating interaction regions (CIRs), which act as clocks and enable the spin period to be determined. Ignace and his team will monitor WR stars to look for CIRs. They will determine the spin period and further interpret these observations using their theoretical models to help us understand how wind features are formed. Undergraduate students will be recruited for a summer research program. Ignace and his team will develop a planetarium show for the general public and local high schools. The show on “space weather” will include a segment on how CIR’s in the Solar wind can enhance geomagnetic storms. The team will enhance an existing Monte Carlo radiative transfer code to characterize how rotational effects can modulate the wind and form CIRs. The comparison of the models to observations with the Echelle SpectroPolarimetric Device for the Observation of Stars on the Canada France Hawaii Telescope will result in a robust picture of the complex structures in WR winds. For the first time, the team will be able to relate electron scattering polarization in thick winds with a model for axisymmetric WR winds, as a function of stellar rotation relative to critical break-up. Modeling both varying and non-varying contributions to polarization is important for measuring periods and constraining mass-loss rates. To complete the picture, the team will model the influence of CIRs on variable IR/radio continuum flux. Polarization probes structures in the inner wind; the long-wavelength continuum probes the asymptotic flow. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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