VIPER: A General Purpose Reduction Software for the Calculation of Precise Stellar Radial Velocities

• Applicant: Professor Dr. Artie P. Hatzes
• Subject Area: Astrophysics and Astronomy
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 546858077

This project will develop a general-purpose software reduction package, Viper, for the calculation of precise stellar radial velocities. In a single reduction package Viper will be able to handle data taken with all techniques used for radial velocity measurements: Traditional ThAr, telluric lines, and iodine absorption cells. Viper can also be used with absorption cells working at near infrared wavelengths and it can also be extended for use with Laser Frequency Combs. An important feature of Viper is that it is easily adapted to new instruments. Viper will be state-of-the-art in that it will incorporate more sophisticated mathematical modeling of the instrumental profile (IP). Changes in the IP represent a major challenge for achieving ultra-precise (< 1 m/s) radial velocities. A part of this the project will explore the use of Machine Learning techniques and Information Field Theory to better parameterize the IP. These may prove superior to current, add hoc methods for doing this. Viper will be the reduction pipeline for three high-resolution spectrographs in Tautenburg (TCES), Ondrjov (OES), and La Silla, Chile (PLATOSpec). These spectrographs will be dedicated to the RV follow-up of transiting candidates found by ESA's PLATO mission. They also will pursue the important science case of extending the parameter space of exoplanets by searching for giant planets in long period orbits. These are the exoplanets that may play a key role in keeping the inner regions of a planetary system habitable. Viper will be open source and readily available to the astronomical community. The flexibility and ease of use of Viper will enable astronomers to use a wide range of spectrographs for the support of the PLATO mission without the need of developing their own high precision radial velocity pipeline. The PLATO mission will require considerable ground-based resources for follow-up radial velocity measurements of the exoplanet candidates that it will discover. Having a general purpose, easy to use radial velocity reduction program may encourage the exoplanet community to use a wide range of facilities for the ground-based follow-up PLATO exoplanets.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Markus Roth