First Light results from PARAS: The PRL Echelle Spectrograph

TL;DR

This paper reports the first light commissioning of the PRL Echelle Spectrograph, demonstrating its high resolution, stability, and potential for exoplanet radial velocity searches with promising initial results.

Contribution

It introduces the first light results of a new high-resolution spectrograph designed for exoplanet detection, highlighting its stability and future improvements.

Findings

Achieved initial spectral stability of 3.7 m/s

Spectrograph covers 3700A to 8600A at R ~ 63,000

Expected to reach 1 m/s stability with vacuum enclosure

Abstract

We present the first light commissioning results from the Physical Research Laboratory (PRL) optical fiber-fed high resolution cross-dispersed Echelle Spectrograph. It is capable of a single- shot spectral coverage of 3700A to 8600A at R ~ 63,000 and is under very stable conditions of temperature (0.04{\deg}C at 23{\deg}C). In the very near future pressure control will also be achieved by enclosing the entire spectrograph in a low-pressure vacuum chamber (~0.01mbar). It is attached to a 1.2m telescope using two 50micron core optical fibers (one for the star and another for simultaneous Th-Ar spectral calibration). The 1.2m telescope is located at Mt. Abu, India, and we are guaranteed about 80 to 100 nights a year for observations with the spectrograph. The instrument will be ultimately used for radial-velocity searches of exoplanets around 1000 dwarf stars, brighter than 10th magnitude, for the next 5 years with a precision of 3 to 5m/s using the simultaneous Th-Ar spectral lamp reference technique. The spectrograph has already achieved a stability of 3.7m/s in short-term time scale and in the near future we expect the stability to be at 1m/s once we install the spectrograph inside the vacuum chamber.