MARVEL - an array of four telescopes feeding a stabilised spectrograph for high-precision radial velocities of stars

Tkachenko, Andrew; Vandenbussche, Bart; Van Winckel, Hans; Raskin, Geert; Brandeker, Alexis; Buchhave, Lars; Glasse, Alistair; Gudel, Manuel; Palle, Enric; Pollacco, Don; Ribas, Ignasi; Schwab, Christian; Sturmer, Julian; Tinetti, Giovanna; Pember, Jacob; Reggiani, Maddalena; Hakim, Kaustubh
Bibliographical reference

EAS2024

Advertised on:
7
2024
Number of authors
17
IAC number of authors
1
Citations
0
Refereed citations
0
Description
Mercator Array for Radial VELocities (MARVEL) is an ensemble of four 80-cm off the shelf telescopes feeding a single stabilised high-resolution (R>90 000) echelle spectrograph. The facility is currently under construction and will be located on La Palma (Canary Islands), next to the Mercator telescope. The facility is designed such that the four telescopes will be able to observe the same (presumably fainter) object in a concert, transmitting stellar light to the spectrograph through optical fibers. Alternatively, the four telescopes will be able to act independently by pointing at four different (presumably brighter) objects whose spectra will be recorded on the same detector. The instrument is planned for commissioning in 2025 with the start of on-sky science operations being planned in the same year or in early 2026. By design, the MARVEL instrument aims at 1m/s radial velocity (RV) precision calculated from the 390-920 nm spectra with a peak signal-to-noise ratio (S/N) of 200 (measured at 550 nm) for a star of spectral type F. The above quoted S/N value and RV precision can be achieved within a one hour exposure for a mV=8.9 and mV=10.9 star with the use of a single and all four telescopes, respectively. These specifications put MARVEL in an excellent position to join the cohort of ground-based facilities whose main focus is on providing pivotal spectroscopic information for exoplanet characterisation. In particular, MARVEL is positioned exceptionally well to provide ground-based spectroscopic follow-up for the vast majority of PLATO candidate exoplanet hosts whose suspected planets have masses in the regime of sub-Neptunes or heavier. In this oral contribution, we will provide a short overview of technical specifications of the instrument and will focus on a more elaborate presentation of the scientific rationale of the MARVEL facility. Besides exoplanets, MARVEL will focus on detailed characterisation of stellar activity, where we will study both the effects of activity on the precision and accuracy of the RV inference and physics of the phenomenon itself.