M dwarfs in the Local Milky Way: The Field Low-Mass Stellar Luminosity and Mass Functions
- Univ. of Washington, Seattle, WA (United States)
Modern sky surveys, such as the Sloan Digital Sky Survey (SDSS) and the Two-Micron All Sky Survey, have revolutionized how Astronomy is done. With millions of photometric and spectroscopic observations, global observational properties can be studied with unprecedented statistical significance. Low-mass stars dominate the local Milky Way, with tens of millions observed by SDSS within a few kpc. Thus, they make ideal tracers of the Galactic potential, and the thin and thick disks. In this thesis dissertation, I present my efforts to characterize the local low-mass stellar population, using a collection of observations from the Sloan Digital Sky Survey (SDSS). First, low-mass stellar template spectra were constructed from the co-addition of thousands of SDSS spectroscopic observations. These template spectra were used to quantify the observable changes introduced by chromospheric activity and metallicity. Furthermore, the average ugriz colors were measured as a function of spectral type. Next, the local kinematic structure of the Milky Way was quantified, using a special set of SDSS spectroscopic observations. Combining proper motions and radial velocities (measured using the spectral templates), along with distances, the full UVW space motions of over 7000 low-mass stars along one line of sight were computed. These stars were also separated kinematically to investigate other observational differences between the thin and thick disks. Finally, this dissertation details a project designed to measure the luminosity and mass functions of low-mass stars. Using a new technique optimized for large surveys, the field luminosity function (LF) and local stellar density profile are measured simultaneously. The sample size used to estimate the LF is nearly three orders of magnitude larger than any previous study, offering a definitive measurement of this quantity. The observed LF is transformed into a mass function (MF) and compared to previous studies.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 946860
- Report Number(s):
- FERMILAB-THESIS-2006-66; TRN: US200903%%1015
- Country of Publication:
- United States
- Language:
- English
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