| dc.description.abstract | In this thesis, we discuss the design and construction of high-resolution spectrometers
for exoplanet discovery and characterisation across the entire scope of project
budgetary regimes. As with all aspects of astronomy, light and more specifically electromagnetic
waves are our greatest key to unlocking the secrets of exoplanetary systems.
The radial velocity method, in which analysis of the Doppler shift of star light
can infer the existence and minimum mass of an exoplanetary system, relies wholly
on the application of high-resolution, stable spectrometer systems. Alongside this,
powerful spectroscopic techniques such as: transit and cross-correlation spectroscopy
(used to probe the atmospheric characteristics of planets), the Rossiter-McLaughlin
effect (which can infer spin-orbit characteristics of the planetary system) and reflected light analysis of a planet (that allow us to discover orbital characteristics and true mass of a planet) require field leading spectrometer design.
These investigative techniques alone more than warrant the existence of large,
high-cost, ultra-stable, high-resolution spectrograph systems, such as HARPS, PFS,
ESPRESSO e.t.c. However, with ever changing science goals, there is scope for a new
kind of instrument. With growing discussion amongst the exoplanet community on
the application of combined high contrast imaging and high dispersion spectroscopy
in exoplanet science, there is a need for replicable, low-cost, stable, high-resolution
spectrometer systems for integral field applications; which can be efficiently coupled
to high contrast imagers.
This thesis presents the design and construction of such an instrument, with a
proof of concept prototype spectrometer produced which is compact (comparable
in size to a 3U CubeSat chassis), low-cost (<£10; 000), highly-replicable (utilising
mostly commercially-o -the-shelf components), stable (demonstrated RV precision
of approximately 20m/s) and high-resolution (resolving power > 60; 000).
Sub-systems for this instrument, a fibre coupling system and a data-reduction
pipeline, are designed and constructed with the complete instrument successfully
tested on-sky at the QMUL Astronomy Unit Observatory.
The design aspects of this system are further employed in the design study of
a large-scale, high-budget, ultra-stable, red-NIR, high-resolution spectrometer concept:
NEREA (Near Earths and high-Res Exoplanet Atmospheres). If funded, this
instrument is to be efficiently coupled to The Gran Telescopio Canarias (GTC). The
combination of the 10m aperture of the GTC and the high-resolution, stable spectroscopy of NEREA will open up opportunities to investigate exoplanetary systems
which are currently unobtainable with contemporary instrumentation.
Finally, all of the experience gained through the completion of these projects is
channelled into the construction of a `Spectrometer Design Toolkit' software which
aids in the rapid design of spectrograph concepts. This system is tested in the
re-design of the collimating/re-focussing lens for EXOhSPEC (EXOplanet high resolution
SPECtrograph), a compact, high-resolution spectrograph in development at
the University of Hertfordshire for the Thai National Observatory (TNO). | en_US |
