Radial velocity measurements and orbit solution

Radial velocity measurements and orbit solution. These plots are based on high-resolution, near-infrared spectra of 2MASS J05352184–0546085 with the PHOENIX spectrograph (resolving power of 30,000) at the 8-meter Gemini South telescope on eight separate nights from December 2002 to January 2003. A cross-correlation analysis of the individual spectra against a radial velocity standard star yields the radial velocities of the two components at eight distinct orbital phases. 

The team tried several different radial velocity standard stars with spectral types M1to M9, and found that an M6.5 star produced the strongest cross-correlation signals for both components; the spectra of the two components are therefore probably similar to that of an M6.5 spectral type. Here the individual, heliocentric radial velocity measurements of the components of 2MASS J05352184–0546085 are shown, as functions of both time (a) and orbital phase (b). Orbital phase is measured with respect to the time of periastron passage (that is, closest approach of the two brown dwarfs to one another), as determined from the final orbit solution. Measurements of the primary are represented as triangles; the secondary as circles. The typical uncertainty on the radial velocity measurements is 2 kilometers/second. The final orbit solution was determined by simultaneously fitting the light-curve and radial velocity measurements using a standard detached-eclipsing-binary model. This orbit solution is shown in a and b as solid curves, green for the more massive component, red for the less massive component. The reduced chi-squared of the fit is 1.0.