Charles Kuehn

PhD, Michigan State University, 2011
Area of Study: Astronomy & Astrophysics

MS, Michigan State University, 2008
Area of Study: Astronomy & Astrophysics

BS, Ohio State University, 2005
Area of Study: Astronomy

Assistant Professor, University of Northern Colorado
Physics & Astronomy (2015 – present)

Postdoctoral Fellow, University of Sydney
SIEF John Stocker (2012-2015)

Postdoctoral Researcher, Michigan State University
(2011-2012)

Adjunct Professor, Aquinas College
(2011-2012)

Adjunct Professor, Lansing Community College
(2011)

Astronomy

My research interests include pulsating variable stars and asteroseismology, stellar structure, exoplanet atmospheres and climates, and astronomy education. I am also interested in the physics of sports.

Finding Additional Planets in Systems with Known Exoplanets

NASA’s TESS mission searches for exoplanets using the transit method (detecting a decrease in the brightness of a star due to a planet passing between us and the star). In a single planet system, the time between transits is constant, however this is not the case in multiple planet systems as the gravitational interactions between the planets constantly create small changes in their orbital periods. Thus, additional planets can be found by looking for small changes in the times between successive planets.

Finding Binary RR Lyrae Stars

RR Lyrae are a class of variable stars with ages around 10-12 billion years. They vary in brightness due to radial pulsations which occur with very regular periods. In this project we are looking for RR Lyrae stars in binary systems by looking at changes in their observed pulsation period due to changes in the star’s distance from other that occurs as a result of the star orbiting around the center of mass in its binary system. There changes in observed pulsational period would be small and thus you need observations with a very short cadence in order to detect these changes. The recently completed Kepler/K2 mission and the ongoing TESS mission provide the best possible data sets for this kind of work. 
 
RR Lyrae stars in binary systems would be very useful for a variety of reasons. RR Lyrae masses are currently calculated using their pulsation properties; finding a RR Lyrae in a binary system would provide an independent method of determining the mass of that star, allowing for us to determine that accuracy of masses calculated from pulsational properties. RR Lyrae in binary systems would also provide valuable insights into the nature of mass transfer between stars in a binary. 

This is a high risk, high reward project as only a small percentage of RR Lyrae are expected to be in a binary system.

Identifying Barriers to Participation in Introductory Astronomy Lab

Astronomy labs are unique compared to other science labs in that they tend to take place at night, in dark, often remote locations on or near college campuses. The nature of these locations may create barriers that limit or alter the nature of student participation in labs. Specifically, these locations may present accessibility issues to students with certain physical disabilities or cause concerns about student safety either at lab or on the way to lab.

Planetary Weather

An effort to understand atmospheric dynamics on other planets will be taken on by one student and faculty from the Departments of Physics and Astronomy and Earth and Atmospheric Sciences at UNC. This work will include understanding and simulating atmospheric models of various planets with the intent of informing our understanding of Earth’s weather.

Areas of Interest

Astronomy – variable stars, Milky Way formation. Astronomy education research.

• Kuehn, C.A., Smith, H.A., Catelan, M., Kunder, A. 2016, in prep, Trends in RR Lyrae Physical Properties with Oosterhoff Type
• Murphy, S.J., Corbally, C.J., Gray, R.O., Cheng, K., Neff, J.E., Koen, C., Kuehn, C.A., Newsome, I., Riggs, Q. 2015, PASA, 32, 36, An Evaluation of the Membership Probability of 212 lambda Boo Stars. I. A Catalogue
• Kennedy, C.R., Stancliffe, R.J., Kuehn, C.A., Beers, T.C., Kinman, T.D., Placco, V.M., Reggiani, H., Rossi, S., Lee, Y.S. 2014, ApJ, 787, 6, Seven New Carbon-enhanced Metal-poor RR Lyrae Stars
• Alonso-Garc´ıa, J., Catelan, M., Amigo, P., Cort´es, C., Kuehn, C.A., Grundahl, F., Lo´pez, G., Salinas, R., Smith, H.A., Stetson, P.B., Swigart, A.V., Valcarce, A.A.R., Zoccali, M. 2014, Memorie della Societa Astronomica Italiana, 85, 287, Multiple populations in Galactic globular clusters from a Stro¨mgren perspective
• Kuehn, C.A., Dame, K., Smith, H.A., Catelan, M., Jeon, Y.B., Nemec, J.M., Walker, A.R., Kunder, A., Pritzl, B.J., De Lee, N., Borissova, J. 2013, AJ, 145, 160, Variable Stars in Large Magellanic Cloud Globular Clusters III: Reticulum
• Benomar, O., Bedding, T.R., Mosser, B., Stello, D., Belkacem, K., Garcia, R.A., White, T.R., Kuehn, C.A., Deheuvels, S., Christensen-Dalsgaard, J. 2013, ApJ, 767, 158, Properties of Oscillation Modes in Subgiant Stars Observed by Kepler
• Richardson, C.T., Baldwin, J.A., Ferland, G.J., Loh, E.D., Kuehn, C.A., Fabian, A.C., Salome´, P. 2013, MNRAS, 430, 1257, The Nature of the H2-emitting Gas in the Crab Nebula
• Kuehn, C.A., Smith, H.A., Catelan, M., Pritzl, B.J., De Lee, N., Borissova, J. 2012, AJ, 144, 186, Variable Stars in Large Magellanic Cloud Globular Clusters II: NGC 1786
• Dall’Ora, M., Kinemuchi, K., Ripepi, V., Rodgers, C.T., Clementini, G., Di Fabrizio, L., Smith, H.A., Marconi, M., Musella, I., Greco, C., Kuehn, C.A., Catelan, M., Pritzl, B.J., Beers, T.C., 2012, ApJ, 752, 42, Stellar Archaeology in the Galactic Halo with the Ultra-faint Dwarfs VI: Ursa Major II
• Kuehn, C., Smith, H.A., Catelan, M., Pritzl, B.J., De Lee, N. 2011, AJ, 142, 107, Variable Stars in Large Magellanic Cloud Globular Clusters I: NGC 1466
• Dall’Ora, M., Kinemuchi, K., Ripepi, V., Rodgers, C.T., Clementini, G., Di Fabrizio, L., Smith, H.A., Marconi, M., Musella, I., Greco, C., Kuehn., C., Catelan, M., Pritzl, B.J., Beers, T.C., 2011, submitted to ApJ, Stellar Archaelogy in the Galactic halo with the Ultra-Faint Dwarfs: VI. Stellar Populations in the Ursa Major II dwarf galaxy
• Contreras, R., Catelan, M., Smith, H.A., Pritzl, B.J., Borissova, J., Kuehn, C., 2010, AJ, 140, 1766, Time-Series Photometry of Globular Clusters: M62 (NGC 6266), the Most RR Lyrae-Rich Globular Cluster in the Galaxy?
• Rabidoux, K., Smith, H.A., Pritzl, B.J., Osborn, W., Kuehn, C., Randall, J., Lustig, R., Wells, K., Taylor, L., De Lee, N., Kinemuch, K., LaCluyz´e, A., Hartley, D., Greenwood, C., Ingber, M., Ireland, M., Pellegrini, E., Anderson, M., Purdum, G., Lacy, J., Curtis, M., Smolinski, J., Danford, S., 2010, AJ, 139, 2300, Light Curves and Period Changes of Type II Cepheids in the Globular Clusters M3 and M5
• Musella, I., Clementini, G., Ripepi, V., Dall’Ora, M., Marconi, M., Greco, C., Moretti, M.I., Kine- muchi, K., Di Fabrizio, L., Smith, H.A., Kuehn, C., Rodgers, C.T., Beers, T.C., Catelan, M., Pritzl, B.J., 2010, Memorie della Societa Astronomica italiana, 14, 55, Stellar Archaeology in the Milk Way Halo. Variable Stars and Stellar Populations in the New Milky Way Satellites Discovered by the SDSS
• Moretti, M.I, Dall’Ora, M., Ripepi, V., Clementini, G., Di Fabrizio, L., Smith, H.A., De Lee, N., Kuehn, C., Catelan, M., Marconi, M., Musella, I., Beers, T.C., Kinemuchi, K., 2009, ApJ, 699L, 125, The Leo IV Dwarf Spheroidal Galaxy: Color-Magnitude Diagram and Pulsating Stars
• Greco, C., Dall’Ora, M., Clementini, G., Ripepi, V., Di Fabrizio, L., Kinemuchi, K., Marconi, M., Musella, I., Smith, H.A., Rodgers, C.T., Kuehn, C., Beers, T.C., Catelan, M., Pritzl, B.J., 2008, ApJ, 675L, 73, On the Newly Discovered Canes Venatici II dSph Galaxy
• Kuehn, C., Kinemuchi, K., Ripepi, V., Clementini, G., Dall’Ora, M., Di Fabrizio, L., Rodgers, C.T., Greco, C., Marconi, M., Musella, I., Smith, H.A., Catelan, M., Beers, T.C., Pritzl, B.J., 2008, ApJ, 674L, 81, Variable Stars in the Newly Discovered Milky Way Dwarf Spheroidal Satellite Canes Venatici I
• Kuehn, C., Baldwin, J.A., Peterson, B.M., Korista, K.T., 2008, ApJ, 673, 69, On The Size of the Fe II-emitting Region in the AGN Arakelian 120
• Dall’Ora, M., Clementini, G., Ripepi, V., Kinemuchi, K., Greco, C., Kuehn, C., Musella, I., Rodgers, C.T., Di Fabrizio, L., Beers, T.C., Catelan, M., Marconi, M., Pritzl, B.J., Smith, H.A., 2008, Memorie della Societa Astronomica italiana, 79, 701, Stellar Populations of the Newly Discovered Satellites of the Milky Way
• Dall’Ora, M., Clementini, G., Kinemuchi, K., Ripepi, V., Marconi, M., Di Criscienzo, M., di Fabrizio, L., Greco, C., Rodgers, C.T., Kuehn, C., Smith, H.A., 2007, IAUS, 241, 331, RR Lyrae Stars in the Bootes Structure
• Bentz, M.C., Denney, K.D., Cackett, E.M., Dietrich, M., Fogel, J.K.J., Ghosh, H., Horne, K.D.,
• Kuehn, C., Minezaki, T., Onken, C.A., Peterson, B.M, Pogge, R.W., Pronik, V.I., Richstone, D.O., Sergeev, S.G., Vestergaard, M., Walker, M.G., Yoshii, Y., 2007, ApJ, 662, 205, NGC 5548 in a Low-Luminosity State: Implications for the Broad-Line Region
• Dall’Ora, M., Clementini, G., Kinemuchi, K., Ripepi, V., Marconi, M., Di Fabrizio, L., Greco, C., Rodgers, C.T., Kuehn, C., Smith, H.A., 2006, ApJ, 653L, 109, Variable Stars in the Newly Discovered Milky Way Satellite in Bootes
• Denney, K.D., Bentz, M.C., Peterson, B.M., Pogge, R.W., Cackett, E.M., Dietrich, M., Fogel, J.K.J., Ghosh, H., Horne, K.D., Kuehn, C., Minezake, T., Onken, C.A., Pronik, V.I., Richstone, D.O., Sergeev, S.G., Vestergaad, M., Walker, M.G., Yoshii, Y., 2006, ApJ, 653, 152, The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping
• Bentz, M.C., Denney, K.D., Cackett, E.M., Dietrich, M., Fogel, J.K.J., Ghosh, H., Horne, K., Kuehn, C., Minezaki, T., Onken, C.A., Peterson, B.M., Pogge, R.W., Pronik, V.I., Richstone, D.O., Sergeev, S.G., Vestergaard, M., Walker, M.G., Yoshii, Y., 2006, ApJ, 651, 775, A Reverberation-based Mass for the Central Black Hole in NGC 4151