Peter Plavchan, Assistant Professor, Physics and Astronomy, and his collaborators are using a High Resolution Echelle Spectrometer (HIRES) to observe a newly discovered, Neptune-like planet, AU Mic, to obtain precise radial velocities (RVs).
Radial velocity (RV) is the motion of a celestial object towards or away from the Sun.
AU Mic hosts a transiting planet, which has been confirmed with the RV method of exoplanet detection. However, its young age presents a challenge with large apparent RV signals due to stellar activity, which are comparable in amplitude to the planetary signals. Therefore, AU Mic is an excellent test case for probing the disentanglement of activity and planet RV signals.
The researchers require simultaneous observations with HIRES, and with iSHELL/IRTF. iSHELL is a high-resolution 1.1-5.3 micron spectrograph for the NASA Infrared Telescope Facility (IRTF) on Maunakea in Hawaii.
Both facilities are in the same location and subject to similar weather, and the researchers can obtain similar precisions (~3 m/s for iSHELL). The simultaneity of the proposed observations allows them to isolate the activity signal from the planetary signals by computing the RV "color" (HIRES - iSHELL velocity difference). More RVs will further constrain the orbital parameters and mass of the known transiting planet, and allow the researchers to search for longer period planets.
Plavchan received $14,875 from NASA for this work. Funding began in June 2020 and will end in late September 2020.
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