| NSF Org: |
AST Division Of Astronomical Sciences |
| Recipient: |
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| Initial Amendment Date: | August 30, 2021 |
| Latest Amendment Date: | July 28, 2023 |
| Award Number: | 2137787 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Daniel Fabrycky
dfabryck@nsf.gov (703)292-8490 AST Division Of Astronomical Sciences MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | January 1, 2022 |
| End Date: | December 31, 2024 (Estimated) |
| Total Intended Award Amount: | $105,535.00 |
| Total Awarded Amount to Date: | $105,535.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
2601 W AVENUE N SAN ANGELO TX US 76909-5099 (325)942-2530 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
2601 West Avenue N San Angelo TX US 76909-5099 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | OFFICE OF MULTIDISCIPLINARY AC |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). RR Lyrae stars are a class of variable star whose pulsations have a relatively straightforward relationship to their intrinsic luminosities. As such, these stars provide a ?standard candle? against which to measure distance throughout the galaxy (and even to other galaxies). Because of their role in setting distance scales throughout the universe, pulsations of RR Lyrae stars continue to be studied decades after the broad outline of the mechanism was first described. Any change in that understanding could have significant implications on other parts of astronomy. The team will study changes in the amplitude of the fundamental mode of pulsation, along with its first overtone, as well as non-radial pulsations on these otherwise radially pulsing stars. They will make ground-based spectroscopic observations while the TESS spacecraft conducts photometric observations of the same star, allowing real-time comparison. Undergraduate students, drawn from under-represented groups at a Hispanic Serving Institution, will be involved in all aspects of the research.
The team recently discovered changes in the amplitude of the fundamental pulsation mode of the double-mode RR Lyrae star V338 Boo. The fundamental pulsation?s amplitude is found to change on the scale of many tens of days, while the first overtone?s amplitude remains constant. Further, other teams have recently discovered non-radial pulsations whose amplitudes also change on the scale of tens of days. The team will observe a set of RR-Lyrae stars to look for similar changes in pulsations, and will furthermore conduct co-incident observsations with the TESS satellite to compare real-time spectroscopic variations with photometric variations. The team will observe known RR Lyrae stars; the study of these modes and variations will inform astrophysical models of stellar interiors.
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.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The goal of this project was to study the ubiquity and behavior of newly discovered transient phenomena found using modern space-based observations of RR Lyrae stars. We have obtained ground-based spectroscopic observations of these variables that coincide with space-based photometric measurements to connect light curve changes to the physical properties of their outer layers. This grant has funded 7 observing runs to McDonald Observatory for a total of 30 nights. We are still in the process of reducing and analyzing some of the data, but our group published a paper in 2023 that showed a modulation in the Blazhko effect of the star LS Her, and another paper in 2024 using newer TESS data to show the complete disappearance of a pulsation mode in the star V338 Boo (we published a paper in 2021 on this star as well). We are also finishing two papers on changes in the turbulent velocity of the stars RU Psc and EV Psc that show cycle to cycle changes. In addition, the PI took students to the January 2023 and January 2024 American Astronomical Society (AAS) meetings to present our work. So, although funding for the project has ended, work is continuing and the project and participation from undergraduate students is ongoing. The reference for the articles we published are:
• Wilhelm, R., Carrell, K., Means, H., Popowicz, A., Bernacki, K., Frąckiewicz, M., Szczepański, M., Dustor, A., Lockett, J., Taylor, J., & Youngquist, S., “Modulation of the Blazhko Cycle in LS Her”, 2023, The Astronomical Journal, 165, 194, doi: 10.3847/1538-3881/acc4ba
• Carrell, K., Wilhelm, R., Tom, A., Smith, H., Popowicz, A., Hug, G., Brincat, S.M., Salvaggio, F., Nakonechny, K., Lee, D., Arranz Heras, T., Vale, T., Mortari, D., Steenkamp, A., Rogge, R., & Checinski, J., “Caught in the Act: Observations of the Double-mode RR Lyrae V338 Boo during the Disappearance of a Pulsation Mode”, 2024, The Astrophysical Journal, 973, 157, doi: 10.3847/1538-4357/ad7094
The broader goals of this project align with the overall goals of the LEAPS-MPS program - to train students from all backgrounds to be the next generation in STEM-related careers. This portion of the grant has been very successful - student participants on observing runs are a good representation of the overall demographics of our university and the surrounding communities. Three student participants in the program graduated in May and August of 2022, two of which are attending graduate school. One of the two pursuing an advanced degree is going into the field of astronomy, and the other is going into physics education research. Four more student participants graduated in May 2024, all of which are attending graduate school and two of these are pursuing advanced degrees in the field of astronomy. The experience of using a world-class telescope and instruments has made a definite impact on all of the students, and has given them the skills and opportunities to further their academic careers and make them more attractive job applicants in the future. Additionally, the opportunity to present our work at the national AAS meetings is an excellent experience for the undergraduate students - they get to hear talks from leaders in various fields of astronomy, and they get to network with their peers and faculty at other institutions. This networking and learning opportunity is extremely valuable for students wanting to attend graduate school, and lead to fruitful connections for many of them.
Last Modified: 05/01/2025
Modified by: Kenneth Carrell
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