9 research outputs found
MARVEL, a four-telescope array for high-precision radial-velocity monitoring
Since the first discovery of a planet outside of our Solar System in 1995,
exoplanet research has shifted from detecting to characterizing worlds around
other stars. The TESS (NASA, launched 2019) and PLATO mission (ESA, planned
launch 2026) will find and constrain the size of thousands of exoplanets around
bright stars all over the sky. Radial velocity measurements are needed to
characterize the orbit and mass, and complete the picture of densities and
composition of the exoplanet systems found. The Ariel mission (ESA, planned
launch 2028) will characterize exoplanet atmospheres with infrared
spectroscopy. Characterization of stellar activity using optical spectroscopy
from the ground is key to retrieve the spectral footprint of the planetary
atmosphere in Ariel's spectra. To enable the scientific harvest of the TESS,
PLATO and Ariel space missions, we plan to install MARVEL as an extension of
the existing Mercator Telescope at the Roque De Los Muchachos Observatory on La
Palma (SPAIN). MARVEL consists of an array of four 80 cm telescopes linked
through optical fibers to a single high-resolution echelle spectrograph,
optimized for extreme-precision radial velocity measurements. It can observe
the radial velocities of four different stars simultaneously or, alternatively,
combine the flux from four telescopes pointing to a single faint target in one
spectrum. MARVEL is constructed by a KU Leuven (Belgium) led collaboration,
with contributions from the UK, Austria, Australia, Sweden, Denmark and Spain.
In this paper, we present the MARVEL instrument with special focus on the
optical design and expected performance of the spectrograph, and report on the
status of the project.Comment: SPIE Astronomical Telescopes + Instrumentation 2020, Ground-based and
Airborne Instrumentation for Astronomy VII
Keck Planet Finder: design updates
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development at the UC Berkeley Space Sciences Laboratory for the W.M. Keck Observatory. KPF is designed to characterize exoplanets via Doppler spectroscopy with a goal of a single measurement precision of 0.3 m s-1 or better, however its resolution and stability will enable a wide variety of astrophysical pursuits. Here we provide post-preliminary design review design updates for several subsystems, including: the main spectrometer, the fabrication of the Zerodur optical bench; the data reduction pipeline; fiber agitator; fiber cable design; fiber scrambler; VPH testing results and the exposure meter
Keck Planet Finder: design updates
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development at the UC Berkeley Space Sciences Laboratory for the W.M. Keck Observatory. KPF is designed to characterize exoplanets via Doppler spectroscopy with a goal of a single measurement precision of 0.3 m s-1 or better, however its resolution and stability will enable a wide variety of astrophysical pursuits. Here we provide post-preliminary design review design updates for several subsystems, including: the main spectrometer, the fabrication of the Zerodur optical bench; the data reduction pipeline; fiber agitator; fiber cable design; fiber scrambler; VPH testing results and the exposure meter
Cardiolipin interactions with proteins
Cardiolipins (CL) represent unique phospholipids of bacteria and eukaryotic mitochondria with four acyl chains and two phosphate groups that have been implicated in numerous functions from energy metabolism to apoptosis. Many proteins are known to interact with CL, and several cocrystal structures of protein-CL complexes exist. In this work, we describe the collection of the first systematic and, to the best of our knowledge, the comprehensive gold standard data set of all known CL-binding proteins. There are 62 proteins in this data set, 21 of which have nonredundant crystal structures with bound CL molecules available. Using binding patch analysis of amino acid frequencies, secondary structures and loop supersecondary structures considering phosphate and acyl chain binding regions together and separately, we gained a detailed understanding of the general structural and dynamic features involved in CL binding to proteins. Exhaustive docking of CL to all known structures of proteins experimentally shown to interact with CL demonstrated the validity of the docking approach, and provides a rich source of information for experimentalists who may wish to validate predictions