Samantha Thompson
A5106228512- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Advanced X-ray Imaging Techniques
- Advanced Measurement and Metrology Techniques
- Optical Systems and Laser Technology
- Calibration and Measurement Techniques
- Space Exploration and Technology
- History and Developments in Astronomy
- Optical measurement and interference techniques
- Radiative Heat Transfer Studies
- CCD and CMOS Imaging Sensors
- Spacecraft and Cryogenic Technologies
- Heat and Mass Transfer in Porous Media
- Advanced Fiber Laser Technologies
- Solid State Laser Technologies
- Origins and Evolution of Life
- Light effects on plants
- Atmospheric Ozone and Climate
Cavendish Hospital
2018-2024
University of Cambridge
2015-2024
Michigan State University
2023
The University of Texas Southwestern Medical Center
2023
Max Planck Institute for Astronomy
2019
Max Planck Society
2019
University of Washington
2018
Wrexham University
2013-2016
University College London
2003-2010
The University of Queensland
2000
The time-variable velocity fields of solar-type stars limit the precision radial-velocity determinations their planets' masses, obstructing detection Earth twins. Since 2015 July we have been monitoring disc-integrated sunlight in daytime using a purpose-built solar telescope and fibre feed to HARPS-N stellar spectrometer. We present analyse measurements cross-correlation function (CCF) parameters obtained first 3 years observation, interpreting them context spatially-resolved observations....
One of the most promising avenues for detailed study temperate Earth-sized exoplanets is detection such planets in transit front stars small and nearby enough to make possible their thorough atmospheric characterisation with next generation telescopes like James Webb Space telescope (JWST) or Extremely Large Telescope (ELT). In this context, TRAPPIST-1 form an unique benchmark system that has gathered interest a large scientific community. The SPECULOOS survey exoplanet survey, targets...
Stellar magnetic activity produces time-varying distortions in the photospheric line profiles of solar-type stars. These lead to systematic errors high-precision radial-velocity measurements, which limit efforts discover and measure masses low-mass exoplanets with orbital periods more than a few tens days. We present new data-driven method for separating Doppler shifts dynamical origin from apparent velocity variations arising variability-induced changes stellar spectrum. show that...
Context. In the age of JWST, temperate terrestrial exoplanets transiting nearby late-type M dwarfs provide unique opportunities for characterising their atmospheres, as well searching biosignature gases. this context, benchmark TRAPPIST-1 planetary system has garnered interest a broad scientific community. Aims. We report here discovery and validation two super-Earths LP 890-9 (TOI-4306, SPECULOOS-2), relatively low-activity (32 pc) M6V star. The inner planet, b, was first detected by TESS...
Abstract State-of-the-art radial-velocity (RV) exoplanet searches are currently limited by RV signals arising from stellar magnetic activity. We analyze solar observations acquired over a 3 yr period during the decline of Carrington Cycle 24 to test models variation Sun-like stars. A purpose-built telescope at High Accuracy Radial-velocity Planet Searcher for Northern hemisphere (HARPS-N) provides disk-integrated spectra, which we extract RVs and <?CDATA...
We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting 13th magnitude K-dwarf in 1.34d orbit. NGTS-4b has mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it well within so-called "Neptunian Desert". The mean density ($3.45\pm0.95$g/cm^3) is consistent with composition 100% H$_2$O or rocky core volatile envelope. likely to suffer significant loss due relatively strong EUV/X-ray irradiation. Its survival Neptunian desert may be an unusually high mass, have...
The clouds of Venus are believed to be composed sulfuric acid (H
Given that the macromolecular building blocks of life were likely produced photochemically in presence ultraviolet (UV) light, we identify some general constraints on which stars produce sufficient UV for this photochemistry. We estimate how much light is needed photochemistry by experimentally measuring rate constant chemistry ("light chemistry", prebiotic synthesis) versus constants bimolecular reactions happen absence ("dark chemistry"). make these measurements representative...
Large sub-Neptunes are uncommon around the coolest stars in Galaxy and rarer still those that metal-poor. However, owing to large planet-to-star radius ratio, these planets highly suitable for atmospheric study via transmission spectroscopy infrared, such as with JWST. Here we report discovery validation of a sub-Neptune orbiting thick-disk, mid-M dwarf star TOI-2406. We first infer properties host by analysing star's near-infrared spectrum, spectral energy distribution, Gaia parallax. use...
Cosmological and exoplanetary science using transformative telescopes like the ELT will demand precise calibration of astrophysical spectrographs in blue-green, where stellar absorption lines are most abundant. Astrocombs-lasers providing a broadband sequence regularly-spaced optical frequencies on multi-GHz grid-promise an atomically-traceable scale, but their realization blue-green is challenging for current infrared-laser-based technology. Here, we introduce concept achieving broad,...
This work assesses the potential capability of next generation high-precision Radial Velocity (RV) instruments for Earth-twin exoplanet detection. From perspective importance data sampling, Terra Hunting Experiment aims to do this through an intense series nightly RV observations over a long baseline on carefully selected target list, via brand-new instrument HARPS3. paper describes end-to-end simulation generating and processing such help us better understand impact uncharacterised stellar...
(Abridged) We perform a detailed study of the main optical activity indicators (Ca II H & K, Balmer lines, Na I D$_{\rm 1}$ 2}$, and He 3}$) measured for Sun using data provided by HARPS-N solar-telescope feed at Telescopio Nazionale Galileo. The value solar rotation period is found in all indicators, with only exception being H$\delta$. derived values vary from 26.29 days (H$\gamma$ line) to 31.23 (He I). From an analysis sliding periodograms we find that most spectral power split into...
Measurements of the physical properties stars at lower end main sequence are scarce. In this context we report masses, radii and surface gravities ten very-low-mass in eclipsing binary systems, with orbital periods order several days. The objects probe stellar mass-radius relation fully convective regime, $M_\star \lesssim 0.35$ M$_\odot$, down to hydrogen burning mass-limit, $M_{\mathrm{HB}} \sim 0.07$ M$_\odot$. were detected by WASP survey for transiting extra-solar planets, as low-mass,...
ABSTRACT SPECULOOS-South, an observatory composed of four independent 1-m robotic telescopes, located at ESO Paranal, Chile, started scientific operation in 2019 January. This Southern hemisphere facility operates as part the Search for Habitable Planets EClipsing ULtra-cOOl Stars (SPECULOOS), international network 1-m-class telescopes surveying transiting terrestrial planets around nearest and brightest ultracool dwarfs (UCDs). To automatically efficiently process observations to deal with...
Radial velocity (RV) searches for Earth-mass exoplanets in the habitable zone around Sun-like stars are limited by effects of stellar variability on host star. In particular, suppression convective blueshift and brightness inhomogeneities due to photospheric faculae/plage starspots dominant contribution such RVs. Gaussian process (GP) regression is a powerful tool statistically modeling these quasi-periodic variations. We investigate limits this technique using 800 days RVs from solar...
Ultraviolet (UV) light has long been invoked as a source of energy for prebiotic chemical synthesis, but experimental support does not involve sources UV that look like the young Sun. Here we experimentally investigate whether flux available on surface early Earth, given favorable atmosphere, can facilitate variety syntheses. We construct solar simulator faint Sun called StarLab. then attempt series reactions testing different aspects scenario involving hydrogen cyanide (HCN), sulfites, and...
ABSTRACT We present a study of photometric flares on 154 low-mass (≤0.2 M⊙) objects observed by the SPECULOOS-South Observatory from 2018 June 1 to 2020 March 23. In this sample, we identify 85 flaring objects, ranging in spectral type M4 L0. detect 234 with energies between 1029.2 and 1032.7 erg, using both automated manual methods. With work, largest sample late-M ultra-cool dwarfs date. By extending previous M dwarf flare studies into regime, find M5–M7 stars are more likely than earlier,...
In the last decade, a dozen close-in giant planets have been discovered orbiting stars with spectral types ranging from M0 to M4, mystery since known formation pathways do not predict existence of such systems. Here, we confirm TOI-4860 b, Jupiter-sized planet an M4.5 host, star at transition between fully and partially convective interiors. First identified TESS data, validate transiting companion's planetary nature through multicolour photometry TRAPPIST-South/North, SPECULOOS, MuSCAT3...
Precise mass measurements of exoplanets discovered by the direct imaging or transit technique are required to determine planet bulk properties and potential habitability. Furthermore, it is generally acknowledged that, for foreseeable future, Extreme Precision Radial Velocity (EPRV) measurement only method potentially capable detecting measuring masses orbits habitable-zone Earths orbiting nearby F, G, K spectral-type stars from ground. In particular, EPRV with a precision better than...
ABSTRACT We present a comprehensive analysis of 10 yr HARPS radial velocities (RVs) the K2V dwarf star HD 13808, which has previously been reported to host two unconfirmed planet candidates. use state-of-the-art nested sampling algorithm PolyChord compare wide variety stellar activity models, including simple models exploiting linear correlations between RVs and indicators, harmonic for signals, more sophisticated Gaussian process regression model. show that overly simplistic are not...
ABSTRACT We present the discovery of TOI-2136 b, a sub-Neptune planet transiting nearby M4.5V-type star every 7.85 d, identified through photometric measurements from Transiting Exoplanet Survey Satellite (TESS) mission. The host is located 33 pc away with radius R* = 0.34 ± 0.02 R⊙, mass $0.34\pm \, \mathrm{M}_{\odot }$, and an effective temperature 3342 100 K. estimate its stellar rotation period to be 75 5 d based on archival long-term photometry. confirm characterize series ground-based...
ABSTRACT Using images from the Helioseismic and Magnetic Imager aboard Solar Dynamics Observatory, we extract radial velocity (RV) signal arising suppression of convective blueshift bright faculae dark sunspots transiting rotating solar disc. We remove these rotationally modulated magnetic-activity contributions simultaneous RVs observed by HARPS-N (High Accuracy Radial Planet Searcher for Northern hemisphere) feed to produce an RV time series magnetically quiet surface (the ‘inactive-region...