Thesis Defense by Daniel Wallace on April 30th
Space Studies master’s student, Daniel Wallace, will defend his thesis as follows. All Space Studies students, faculty and staff are encouraged to attend. Please show your support!
When: Thursday, April 30th at 3:30 p.m. (Central DST)
Where: Ryan Hall, Room 111
Title: An Investigation of Six Poorly Described Close Visual Double Stars Using Speckle Interferometry
About the topic: Many close visual double stars are poorly described by conclusions of binarity and prematurely published calculated orbits based on astrometric observation records which often do not cover the full orbit. Large telescopes with sufficient resolving power can be outfitted with speckle interferometry camera systems to in order to obtain diffraction limited images of close visual binary stars, and carefully calibrated speckle interferometry reduction of these images allows for the determination of new astrometric position measurements. The new speckle interferometry astrometry, typically more accurate than visual micrometric measurements by an order of magnitude, can be combined with previous astrometric data and thus help to further describe the observed binary system. Confirmation of binarity or optical doubles and more constrained orbital parameters are often the result of astrometry completed using the well-attested speckle interferometric technique. Moreover, from recent space-based astrometry missions such as Hipparcos and Gaia, an enormous influx double star observations and data such as more accurate parallax measurements has been assembled and is need of quality follow up work, including further observation and analysis. Coupled with more accurate parallax information, refinements of binary star orbital parameters lead to more constrained estimates of stellar mass, which is the key parameter underpinning our current stellar models that describe stellar formation and evolution. One can see then, that accurate astrometric observations of double stars are critical to our understanding of stars, but unfortunately the number of professional close visual double star observers and programs is small, and time on large telescopes is very competitive; thus, large amounts of double star data are neglected.
A viable solution to the close double star neglect problem and recent decadal survey recommendations regarding training of future scientists, as well as contribution to the field of double star science was demonstrated through the current work, as six poorly described close visual double stars, exhibiting significant deviations from published orbits were astrometrically observed and measured using the speckle interferometry technique at the 2.1-m telescope at Kitt Peak National Observatory in Arizona, USA. The observations and measurements of the target double stars occurred as part of large, collaborative, nine night observing run organized by principal investigator Genet (California Polytechnic Institute) during mid October 2013. The observing run served as a unique learning experience for several students and produced a total of 1.4 terabytes of double star data, which were later reduced and analyzed using the recently developed astrometric software program - PlateSolve3. The new astrometric measurements of the six target double stars show continued trend in significant deviation from previously published orbits, indicating a need for orbital revision. Some observations provided evidence of optical doubles for systems previously thought to exhibit binarity.
About the presenter: Daniel B. Wallace is a 29 year old secondary education science teacher in his 6th year teaching Earth and Space Science in Pennsylvania. Wallace, who has traveled extensively in South America by bicycle (2009), began teaching in Philadelphia, and currently teaches 9th grade Earth and Space Science in the Quakertown, PA. Wallace has been enrolled in the UND MS Space Studies program since the spring of 2012, and has continued working as a full time contracted educator throughout his master’s program at UND. He is extremely active, and outdoor oriented, with an effervescent personality, an enthusiasm for learning and sharing knowledge, and a passion for science. Wallace graduated a dual major from East Stoudsburg University of Pennsylvania (2008): BS Secondary Education, BS General Science and Earth/Space Science. His UND Space Studies focus over the past two years has been mainly planetary science, human factors in space, and astronomy. Wallace’s thesis is the result of collaboration with Dr. Russ Genet (Cal. Poly.) on a nine night speckle interferometry observing run during October 2013 at the 2.1-m KPNO telescope in Arizona, USA. Future career paths may include education and science, possibly in the higher education.
******Those unable to attend in person may view the live webcast******
1) A live webcast which includes PowerPoint slides will be available here. Please note: this option is currently not operational on portable devices/tablets.
2) A simple live webcast is also available here.
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