Research

The Ages of Stars

I have been searching for and studying aging stars in binary star systems within star clusters. For stars in an eclipsing binary system, we are often able to measure their characteristics (like mass and size) with high precision. The size of a rapidly expanding star can subsequently give us its precise age. I have been working to find such stars in clusters  — groups of stars that were born at the same time — so that we can test our measured ages against other techniques in order to better understand the internal mechanisms that make a star work.

For perspective, dating of meteorites using radioactivity puts the Sun and solar system at about 4.57 billion years.

Some of our recent cluster targets:

M11/NGC 6705 (220 million years old)

credit: Jean-Charles Cuillandre/CFHT http://apod.nasa.gov/apod/ap030122.html
credit: Jean-Charles Cuillandre/CFHT
Astronomy Picture of the Day

Reference: Bavarsad, E. A., Sandquist, E. L., Shetrone, M. D., & Orosz, J. A. 2016, Astrophysical Journal, 831, 48.  Link

NGC 6811 (1.1 billion years old) – a cluster observed by the Kepler spacecraft

Reference: Sandquist, E. L., Jessen-Hansen, J., Shetrone, M. D., et al. 2016, Astrophysical Journal, 831, 11. Link

NGC 6819 (2.4 billion years old) – a cluster observed by the Kepler spacecraft

References: Brewer, L. N., Sandquist, E. L., Mathieu, R. D., et al.  2016, Astronomical Journal, 151, 66.  Link

Jeffries, M. W., Jr., Sandquist, E. L., Mathieu, R. D., et al. 2013, Astronomical Journal, 146, 58. Link

Sandquist, E. L., Mathieu, R. D., Brogaard, K., et al. 2013, Astrophysical Journal, 762, 58. Link

NGC 7142 (3.6 billion years old) – pictured at top (credit: Tony Hallas)

Reference: Sandquist, E. L., Shetrone, M., Serio, A. W., & Orosz, J. 2013, Astronomical Journal, 146, 40.  Link