Posted on Thursday, November 14, 2013
Magnetic fields are integrally connected to the life cycle of stars, affecting properties such as temperature, size and radius. For astronomers, understanding these magnetic fields in a more comprehensive way can add perspective to important questions about what it takes for a star to support an Earth-like planet or how planet-forming environments arise.
Still, magnetic fields remain a lesser known component of stars - an area of stellar astronomy that Assistant Professor of Physics Leslie Hebb will explore as the principal investigator of a research project funded by a National Science Foundation (NSF) grant. The three-year project, "Collaborative Research: Mapping small and large scale magnetic fields on low mass stars," will be conducted by Hebb in conjunction with joint research efforts at University of Washington (UW) which will examine solar flares and starspots.
"Over the next decade, understanding how magnetic fields and rotation affect stars will be a major area of focus for astronomers," Hebb says. "While it's inherently interesting to study magnetic fields on stars, it's also important in astronomy to answer questions that have larger consequences, including how planets form or how life may arise. Although measuring magnetic fields is in many ways complicated, through this project we'd like to know as much as we can about its influence on other properties of stars."
By determining magnetic field properties, Hebb says researchers can eventually better understand aspects of stars such as the age of stars, which is fundamentally important to answering bigger questions about stellar and planetary astronomy.
For the research project, Hebb says there are three overarching goals. The first is to observe the presence of small starspots on stars - other than the sun - and determine how mass and rotation affect magnetic fields. The second goal is to investigate the effect of magnetic fields on the temperature, radius and luminosity of stars. The last aim is to determine the importance of both large and small magnetic fields on observable features, including solar flares and emissions from stars.
Part of the resulting research efforts for Hebb's project will include detailed magnetic field and surface brightness maps. Because masses, radii and temperatures will be clearly defined properties, the data will be able to help express the distributions and sizes of magnetically active regions of stars.
As the principal investigator, Hebb is overseeing the research project. She will be collaborating with scientists from other institutions and providing opportunities for HWS students to get involved with the research.
During the project, the Colleges' portion of the NSF grant will support one undergraduate student researcher from HWS each summer for three years. The students will work with Hebb on campus, with the benefit of gaining invaluable experience as they study eclipsing binary stars, important astronomical objects that allow scientists to measure the mass and radius of individual stars.
Hebb says that the broader implications for this research include knowing more about the types of stars that could support the kind of surrounding environment and types of planets that could have the properties necessary for the building blocks of life.
"It's not happening tomorrow, but it's in the sights of scientists," Hebb says. "In order to find that kind of evidence we have to target the right kinds of planets with the right kinds of properties. It's dependent on what kind of star a planet is orbiting. There are many unknowns about magnetic fields of stars, but understanding how those magnetic fields affect stars can improve our understanding of planets."
Hebb joined the HWS faculty in 2012. She received a B.S. in electrical engineering from University of Denver, and her M.S. and Ph.D. in astrophysics from Johns Hopkins University. Hebb also conducted post-doctoral research at University of St. Andrews and at Vanderbilt University. She has served as visiting faculty at University of Washington.