ORCID Profile
0000-0003-1453-0574
Current Organisations
University of Oxford
,
University of Oxford All Souls College
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Related Links
Publications
The Kepler Smear Campaign: Light Curves for 102 Very Bright Stars
Publisher: American Astronomical Society
Date: 17-09-2019
The impact of the GATS on transnational tertiary education: Comparing experiences of New Zealand, Australia, Singapore and Malaysia
Publisher: Springer Science and Business Media LLC
Date: 12-2003
DOI: 10.1007/BF03216799
Robust, open-source removal of systematics in Kepler data
Publisher: Oxford University Press (OUP)
Date: 09-06-2017
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 09-2010
Transiting exoplanets from the CoRoT space mission. XVIII. CoRoT-18b: a massive hot Jupiter on a prograde, nearly aligned orbit
Publisher: EDP Sciences
Date: 09-2011
A Ghost in the Toast: TESS Background Light Produces a False “Transit” Across τ Ceti
Publisher: American Astronomical Society
Date: 04-10-2019
Transiting exoplanets from the CoRoT space mission Resolving the nature of transit candidates for the LRa03 and SRa03 fields
Publisher: Springer Science and Business Media LLC
Date: 06-11-2011
Beyond the Kepler/K2 bright limit: Variability in the seven brightest members of the Pleiades
Publisher: Oxford University Press (OUP)
Date: 11-08-2017
The optical transmission spectrum of the hot Jupiter HAT-P-32b: clouds explain the absence of broad spectral features?
Publisher: Oxford University Press (OUP)
Date: 21-10-2013
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 02-2014
Transiting exoplanets from theCoRoTspace mission
Publisher: EDP Sciences
Date: 02-12-2010
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 11-2010
Transiting exoplanets from theCoRoTspace mission
Publisher: EDP Sciences
Date: 23-11-2010
The K2 Mission: Characterization and Early Results
Publisher: IOP Publishing
Date: 04-2014
DOI: 10.1086/676406
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 09-2010
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 2012
The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
Publisher: American Astronomical Society
Date: 15-03-2022
Abstract: Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme-precision radial-velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The Extreme-precision Spectrograph (EXPRES) Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed radial-velocity (RV) correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when using real data, relative method performance is assessed using the total and nightly scatter of returned RVs and agreement between the results of different methods. Nearly all submitted methods return a lower RV rms than classic linear decorrelation, but no method is yet consistently reducing the RV rms to sub-meter-per-second levels. There is a concerning lack of agreement between the RVs returned by different methods. These results suggest that continued progress in this field necessitates increased interpretability of methods, high-cadence data to capture stellar signals at all timescales, and continued tests like the ESSP using consistent data sets with more advanced metrics for method performance. Future comparisons should make use of various well-characterized data sets—such as solar data or data with known injected planetary and/or stellar signals—to better understand method performance and whether planetary signals are preserved.
A Low-mass Exoplanet Candidate Detected by K2 Transiting the Praesepe M Dwarf JS 183
Publisher: American Astronomical Society
Date: 24-03-2017
Abstract: We report the discovery of a repeating photometric signal from a low-mass member of the Praesepe open cluster that we interpret as a Neptune-sized transiting planet. The star is JS 183 (HSHJ 163, EPIC 211916756), with T eff = 3325 ± 100 K, M * = 0.44 ± 0.04 M ⊙ , R * = 0.44 ± 0.03 R ⊙ , and . The planet has an orbital period of 10.134588 days and a radius of R P = 0.32 ± 0.02 R J . Since the star is faint at V = 16.5 and J = 13.3, we are unable to obtain a measured radial velocity orbit, but we can constrain the companion mass to below about 1.7 M J , and thus well below the planetary boundary. JS 183b (since designated as K2-95b) is the second transiting planet found with K2 that resides in a several-hundred-megayear open cluster both planets orbit mid-M dwarf stars and are approximately Neptune sized. With a well-determined stellar density from the planetary transit, and with an independently known metallicity from its cluster membership, JS 183 provides a particularly valuable test of stellar models at the fully convective boundary. We find that JS 183 is the lowest-density transit host known at the fully convective boundary, and that its very low density is consistent with current models of stars just above the fully convective boundary but in tension with the models just below the fully convective boundary.
Exoplanet transmission spectroscopy using KMOS
Publisher: Oxford University Press (OUP)
Date: 14-09-2015
A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion
Publisher: Springer Science and Business Media LLC
Date: 14-12-2016
DOI: 10.1038/NATURE16068
Abstract: Thousands of transiting exoplanets have been discovered, but spectral analysis of their atmospheres has so far been dominated by a small number of exoplanets and data spanning relatively narrow wavelength ranges (such as 1.1-1.7 micrometres). Recent studies show that some hot-Jupiter exoplanets have much weaker water absorption features in their near-infrared spectra than predicted. The low litude of water signatures could be explained by very low water abundances, which may be a sign that water was depleted in the protoplanetary disk at the planet's formation location, but it is unclear whether this level of depletion can actually occur. Alternatively, these weak signals could be the result of obscuration by clouds or hazes, as found in some optical spectra. Here we report results from a comparative study of ten hot Jupiters covering the wavelength range 0.3-5 micrometres, which allows us to resolve both the optical scattering and infrared molecular absorption spectroscopically. Our results reveal a erse group of hot Jupiters that exhibit a continuum from clear to cloudy atmospheres. We find that the difference between the planetary radius measured at optical and infrared wavelengths is an effective metric for distinguishing different atmosphere types. The difference correlates with the spectral strength of water, so that strong water absorption lines are seen in clear-atmosphere planets and the weakest features are associated with clouds and hazes. This result strongly suggests that primordial water depletion during formation is unlikely and that clouds and hazes are the cause of weaker spectral signatures.
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 07-06-2011
CSI 2264: SIMULTANEOUS OPTICAL AND INFRARED LIGHT CURVES OF YOUNG DISK-BEARING STARS IN NGC 2264 WITHCoRoTandSPITZER—EVIDENCE FOR MULTIPLE ORIGINS OF VARIABILITY
Publisher: American Astronomical Society
Date: 13-03-2014
CSI 2264: CHARACTERIZING ACCRETION-BURST DOMINATED LIGHT CURVES FOR YOUNG STARS IN NGC 2264
Publisher: American Astronomical Society
Date: 13-03-2014
Gaussian processes for time-series modelling
Publisher: The Royal Society
Date: 13-02-2013
Abstract: In this paper, we offer a gentle introduction to Gaussian processes for time-series data analysis. The conceptual framework of Bayesian modelling for time-series data is discussed and the foundations of Bayesian non-parametric modelling presented for Gaussian processes . We discuss how domain knowledge influences design of the Gaussian process models and provide case ex les to highlight the approaches.
Transiting exoplanet candidates fromK2Campaigns 5 and 6
Publisher: Oxford University Press (OUP)
Date: 08-06-2016
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 03-2010
HII 2407: AN ECLIPSING BINARY REVEALED BY K2 OBSERVATIONS OF THE PLEIADES
Publisher: American Astronomical Society
Date: 17-11-2015
The K2 Bright Star Survey. I. Methodology and Data Release
Publisher: American Astronomical Society
Date: 11-2019
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 02-2012
Ground-based photometry of space-based transit detections: photometric follow-up of the CoRoT mission
Publisher: EDP Sciences
Date: 15-07-2009
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 05-2012
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 07-2013
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 09-2010
CSI 2264: Probing the inner disks of AA Tauri-like systems in NGC 2264
Publisher: EDP Sciences
Date: 23-04-2015
A Gemini ground-based transmission spectrum of WASP-29b: a featureless spectrum from 515 to 720 nm
Publisher: Oxford University Press (OUP)
Date: 29-11-2013
DOI: 10.1093/MNRAS/STS307
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 08-03-2011
K2SC: Flexible systematics correction and detrending ofK2light curves using Gaussian Process regression
Publisher: Oxford University Press (OUP)
Date: 12-04-2016
DOI: 10.1093/MNRAS/STW706
Keplerobservations of the asteroseismic binary HD 176465
Publisher: EDP Sciences
Date: 05-2017
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 2012
A uniform analysis of HD 209458b Spitzer/IRAC light curves with Gaussian process models
Publisher: Oxford University Press (OUP)
Date: 28-05-2015
DOI: 10.1093/MNRAS/STV910
K2 photometry and HERMES spectroscopy of the blue supergiant ρ Leo: rotational wind modulation and low-frequency waves
Publisher: Oxford University Press (OUP)
Date: 09-02-2018
DOI: 10.1093/MNRAS/STY308
Transiting exoplanets from the CoRoT space mission
Publisher: EDP Sciences
Date: 28-08-2012
Related Organisations
University Of Exeter
Location: United Kingdom of Great Britain and Northern Ireland
University Of Oxford
Location: United Kingdom of Great Britain and Northern Ireland
Imperial College London
Location: United Kingdom of Great Britain and Northern Ireland
University Of Cambridge
Location: United Kingdom of Great Britain and Northern Ireland
University Of Oxford All Souls College
Location: United Kingdom of Great Britain and Northern Ireland
Related Funding Activities
The Formation And Evolution Of Stars
Start Date: 2008
End Date: 2011
Funder: Science and Technology Facilities Council
View Funded Activity