Identifying Spectroscopic Binaries in SDSS-IV/ APOGEE-2 with the R Statistic
Research Mentor(s)
Covey, Kevin R.
Description
Stellar paired star systems provide astronomers with the only tools of directly measuring a star’s mass. To astronomers, these paired star systems are called binaries. Before we can measure said masses, these systems of interest must be identified. The SDSS-IV/APOGEE-2 survey obtains high resolution spectra that can reveal the presence of spectral lines from both members of a binary pair. The APOGEE spectrograph observes roughly 250 stars simultaneously, making it a remarkably efficient instrument for identifying infrared-bright binary systems. These systems have low-mass stars which are the objects we seek to identify. We present the criteria that reliably identifies binary stars on the basis of asymmetries and distinct dual peaks in their cross correlation functions (CCFs). A cross correlation function, generated by APOGEE, measures the agreement between modeled spectra and observed spectra. The asymmetries present in the CCFs are found by application of the R statistic which summarizes the amount of symmetry and structure in a CCF. Binary systems have the presence of two peaks in their CCFs which acts as a good secondary method for detecting these systems. Currently, we are applying conservative thresholds to the statistics we are using to identify binaries, while continuing examine how our method can be adjusted to maximize the size of our binary sample.
Document Type
Event
Start Date
17-5-2017 12:00 PM
End Date
17-5-2017 3:00 PM
Department
Physics/Astronomy
Genre/Form
student projects; posters
Subjects – Topical (LCSH)
Double stars--Observations
Type
Image
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this documentation for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Language
English
Format
application/pdf
Identifying Spectroscopic Binaries in SDSS-IV/ APOGEE-2 with the R Statistic
Stellar paired star systems provide astronomers with the only tools of directly measuring a star’s mass. To astronomers, these paired star systems are called binaries. Before we can measure said masses, these systems of interest must be identified. The SDSS-IV/APOGEE-2 survey obtains high resolution spectra that can reveal the presence of spectral lines from both members of a binary pair. The APOGEE spectrograph observes roughly 250 stars simultaneously, making it a remarkably efficient instrument for identifying infrared-bright binary systems. These systems have low-mass stars which are the objects we seek to identify. We present the criteria that reliably identifies binary stars on the basis of asymmetries and distinct dual peaks in their cross correlation functions (CCFs). A cross correlation function, generated by APOGEE, measures the agreement between modeled spectra and observed spectra. The asymmetries present in the CCFs are found by application of the R statistic which summarizes the amount of symmetry and structure in a CCF. Binary systems have the presence of two peaks in their CCFs which acts as a good secondary method for detecting these systems. Currently, we are applying conservative thresholds to the statistics we are using to identify binaries, while continuing examine how our method can be adjusted to maximize the size of our binary sample.