110 likes | 196 Views
Determining the Properties of GX Gem. Laura Handzel Agnes Scott College, Decatur, GA Dr. Claud Lacy, Mentor University of Arkansas, Fayetteville, AR. GX Gem. Variable star located in Gemini Close eclipsing binary Comprised of two very similar stars orbiting a common center of mass
E N D
Determining the Properties of GX Gem Laura Handzel Agnes Scott College, Decatur, GA Dr. Claud Lacy, Mentor University of Arkansas, Fayetteville, AR
GX Gem • Variable star located in Gemini • Close eclipsing binary • Comprised of two very similar stars orbiting a common center of mass • Younger stars than our sun and possessing a higher metallicity • Provides example of why current stellar evolutionary theories may need to be re-examined
Observations Primary Star Secondary Star Earth • Images taken by Dr. Lacy on the URSA Telescope in the visual range • Observation period ran from November 2001 to April 2006 Variable Comparison Check
Multi-Measure: Used variations in magnitude of the variable, comparison, and check stars to find eclipse dates Multi-Minima 2.2: Determined period from eclipse data Created light curves to find dates of minima Histogram revealing period created from the eclipse data Minima and Period Period=4.037934 days
Photometric Properties • Results for properties came from EBOPP program • 0.5 phase = circular orbit • Two stars have almost equal radii, 0.98+-0.04 radii ratio • Nearly edge-on inclination to Earth at 85.88+-0.09° Primary Eclipse at 0.0 Phase Secondary Eclipse at 0.5 Phase
Properties found with GLSPL and Dr. Torres’ radial velocity data Stars have opposing radial velocities Mass ratio = 0.989+-0.006 System movement of primary = -0.214+-0.301 System movement of the secondary = -1.916+-0.334 Spectroscopic Properties Velocity Curve of the Secondary Velocity Curve of the Primary
Age: 2.376*10^9 years old 65% Hydrogen 32% Helium 3% Heavier Elements 6150 K & 6120 K Age: 4.5*10^9 years old 73.46% Hydrogen 24.85% Helium 1.65% Heavier Elements 5800 K Age and Composition GX Gem Stars Sun
Importance • Current Age: 2.376*109+-6.7*107 years • Shell Hydrogen Burning age: 2.66*109+-3.0*107 years • GX Gem gives evidence that current theories of stellar evolution should be revamped.
GX Gem, Final Look • Appears as a single star varying in brightness • Actually a binary system of F class stars of nearly equal mass and radius • Contains more heavier elements, less hydrogen, and more helium • Good example of how binary evolution can vary from single star evolution
Determining the Properties of GX Gem Laura Handzel Agnes Scott College, Decatur, GA Dr. Claud Lacy, Mentor University of Arkansas, Fayetteville, AR Any Questions?