Determining ages for brown dwarfs is one of the trickiest aspects in our research, yet a very important one as they allow us to estimate masses. One way many researchers estimate ages is by attempting to match the motions of the object to that of stellar moving groups with known ages. A match in XYZ-UVW space can suggest membership which would imply the brown dwarf is coeval with that group. One can calculate XYZ positions and UVW velocities in Python or your favorite programming language. BDNYC is now hosting a stellar kinematics web application that can do this for you.

To use this application you need to supply Right Ascension, Declination, proper motions, radial velocity, and distance. These values can be drawn straight from Simbad (and soon: from our BDNYC database) and one can also specify to calculate XYZUVW for a range of distances or velocities. The application does not store this information on our server, so you don’t have to worry about calculating the kinematics on proprietary data. Note that X and U are positive towards the Galactic center and UVW are not corrected for solar motion.

The results are displayed in a table and a variety of interactive plots generated and linked with Bokeh. Nearby moving groups listed in Malo et al. 2013 are displayed for comparison with your input. You can pan, zoom, resize, and save the figures, and can hover over the data points to examine the kinematics of a specific point. You can also select multiple points, either on the table or on the graph, to highlight them in all plots allowing you to quickly examine which distances/velocities match specific groups. The calculated XYZ-UVW can be saved in several formats for your use elsewhere. Note that these values are not stored on our server You can find the source code for this application on GitHub. It is still being developed and we welcome any feedback.