Khalid Barkaoui
A5054361321- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Space Exploration and Technology
- Solar and Space Plasma Dynamics
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Astronomical and nuclear sciences
- Spectroscopy and Laser Applications
- Adaptive optics and wavefront sensing
- Isotope Analysis in Ecology
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Planetary Science and Exploration
- Methane Hydrates and Related Phenomena
- Optical Systems and Laser Technology
- Radio Astronomy Observations and Technology
- Ionosphere and magnetosphere dynamics
- Spacecraft and Cryogenic Technologies
- Statistical and numerical algorithms
- Astrophysical Phenomena and Observations
University of Liège
2018-2025
Massachusetts Institute of Technology
2022-2025
Instituto de Astrofísica de Canarias
2022-2025
Planetary Science Institute
2022-2024
Perth Exoplanet Survey Telescope Observatory
2024
Royal Astronomical Society
2024
Universidad de La Laguna
2024
Cadi Ayyad University
2017-2023
Institute of Astrophysics and Space Sciences
2023
Manchester Metropolitan University
2019
Abstract We have collected transit times for the TRAPPIST-1 system with Spitzer Space Telescope over four years. add to these ground-based, HST, and K2 transit-time measurements, revisit an N -body dynamical analysis of seven-planet using our complete set from which we refine mass ratios planets star. next carry out a photodynamical light curves derive density host star planet densities. find that all seven planets’ densities may be described single rocky mass–radius relation is depleted in...
We present TRICERATOPS, a new Bayesian tool that can be used to vet and validate TESS Objects of Interest (TOIs). test the on 68 TOIs have been previously confirmed as planets or rejected astrophysical false positives. By looking in positive probability (FPP) -- nearby (NFPP) plane, we define criteria must meet classified validated (FPP < 0.015 NFPP 10^-3), likely 0.5 positives (NFPP > 10^-1). apply this procedure 384 unclassified statistically 12, classify 125 planets, 52 Of 12 9 are newly...
Wide field surveys for transiting planets are well suited to searching diverse stellar populations, enabling a better understanding of the link between properties and their parent stars. We report discovery HAT-P-69b (TOI 625.01) HAT-P-70b 624.01), two new hot Jupiters around A stars from HATNet survey which have also been observed by Transiting Exoplanet Survey Satellite (TESS). has mass 3.58 +0.58/-0.58 MJup radius 1.676 +0.051/-0.033 RJup, residing in prograde 4.79-day orbit. 1.87...
TRAPPIST-1 is an ultracool dwarf star transited by seven Earth-sized planets, for which thorough characterization of atmospheric properties, surface conditions encompassing habitability and internal compositions possible with current next generation telescopes. Accurate modeling the essential to achieve this goal. We aim obtain updated stellar parameters TRAPPIST- 1 based on new measurements evolutionary models, compared those used in discovery studies. present a measurement parallax...
Abstract Many of the known hot Jupiters are formally unstable to tidal orbital decay. The only Jupiter for which decay has been directly detected is WASP-12, transit-timing measurements spanning more than a decade have revealed that period decreasing at rate <?CDATA ${dP}/{dt}\approx {10}^{-9}$?> , corresponding reduced quality factor about 2 × 10 5 . Here, we present compilation data WASP-12 and 11 other systems especially favorable detecting decay: KELT-16; WASP-18, 19, 43, 72, 103, 114,...
Abstract We present an estimate of the occurrence rate hot Jupiters (7 R ⊕ ≤ p 2 J , 0.8 P b 10 days) around early-type M dwarfs based on stars observed by Transiting Exoplanet Survey Satellite (TESS) during its primary mission. adopt stellar parameters from TESS Input Catalog and construct a sample 60,819 with 10.5 T mag 13.5, effective temperatures 2900 eff 4000 K, masses 0.45 * 0.65 ⊙ . conduct uninformed transit search using detection pipeline box least square characterize searching...
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 NASA’s Transiting Exoplanet Survey Satellite (TESS) mission promises to improve our understanding of hot Jupiters by providing an all-sky, magnitude-limited sample transiting suitable for population studies. Assembling such a requires confirming hundreds planet candidates with additional follow-up observations. Here we present 20 that were detected using TESS data and confirmed be planets through photometric, spectroscopic, imaging observations coordinated the Follow-up Observing...
Abstract JWST has ushered in an era of unprecedented ability to characterize exoplanetary atmospheres. While there are over 5000 confirmed planets, more than 4000 Transiting Exoplanet Survey Satellite (TESS) planet candidates still unconfirmed and many the best planets for atmospheric characterization may remain be identified. We present a sample TESS that we identify as “best-in-class” transmission emission spectroscopy with JWST. These targets sorted into bins across equilibrium...
Abstract We present the discovery and characterization of TOI-4364b, a young mini-Neptune in tidal tails Hyades cluster, identified through TESS transit observations ground-based follow-up photometry. The planet orbits bright M dwarf ( K = 9.1 mag) at distance 44 pc, with an orbital period 5.42 days equilibrium temperature <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>48</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>8</mml:mn> </mml:mrow> <mml:mo>−</mml:mo>...
Abstract TOI-836 is a ∼2–3 Gyr K dwarf with an inner super Earth ( R = 1.7 ⊕ , P 3.8 days) and outer mini-Neptune 2.6 8.6 days). JWST/NIRSpec 2.8–5.2 μ m transmission spectra are flat for both planets. We present Keck/NIRSPEC observations of escaping helium super-Earth b, which shows no excess absorption in the 1083 nm triplet to deep limits (<0.2%), c, strong (0.7%) visits. These results demonstrate that planet c retains at least some primordial atmosphere, while b consistent having lost...
We present the discovery and characterisation of two transiting planets observed by Transiting Exoplanet Survey Satellite (TESS) orbiting nearby (d ~ 22 pc), bright (J 9 mag) M3.5 dwarf LTT 3780 (TOI-732). confirm both their association with via ground-based photometry determine masses using precise radial velocities measured CARMENES spectrograph. Precise stellar parameters determined from high resolution spectra that is a mid-M an effective temperature T_eff = 3360 +\- 51 K, surface...
Abstract The relative rarity of giant planets around low-mass stars compared with solar-type is a key prediction from the core-accretion planet formation theory. In this paper we report on discovery four gas that transit late K and early M dwarfs. HATS-74Ab (TOI 737b), HATS-75b 552b), HATS-76b 555b), HATS-77b 730b) were all discovered HATSouth photometric survey follow-up using TESS other facilities. We use new ESPRESSO facility at VLT to confirm systems measure their masses. find these have...
Abstract The Kepler and TESS missions have demonstrated that planets are ubiquitous. However, the success of these heavily depends on ground-based radial velocity (RV) surveys, which combined with transit photometry can yield bulk densities orbital properties. While most host stars too faint for detailed follow-up observations, is detecting orbiting nearby bright more amenable to RV characterization. Here, we introduce TESS-Keck Survey (TKS), an program using ∼100 nights Keck/HIRES study...
We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M-dwarf with stellar mass close to critical at which stars transition from partially fully convective. b was first identified as candidate TESS photometry, and confirmed radial velocities ESPRESSO, ground-based photometry HATSouth, MEarth-South, TRAPPIST-South, LCOGT, ExTrA. find that planet has $\mathrm{0.665\pm0.025\,M_J}$ radius $\mathrm{1.017\pm0.044\,R_J}$. It orbits its host star, orbital period...
Abstract TOI-6255 b (GJ 4256) is an Earth-sized planet (1.079 ± 0.065 R ⊕ ) with orbital period of only 5.7 hr. With the newly commissioned Keck Planet Finder and CARMENES spectrographs, we determine planet’s mass to be 1.44 0.14 M . The just outside Roche limit, P orb / = 1.13 0.10. strong tidal force likely deforms into a triaxial ellipsoid long axis that ∼10% longer than short axis. Assuming reduced stellar quality factor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
We present here SPECULOOS, a new exoplanet transit search based on network of 1m-class robotic telescopes targeting the ~1200 ultracool (spectral type M7 and later) dwarfs bright enough in infrared (K-mag ≤ 12.5) to possibly enable atmospheric characterization temperate terrestrial planets with next-generation facilities like <i>James Webb Space Telescope</i>. The ultimate goals project are reveal frequency around lowest-mass stars brown dwarfs, probe diversity their bulk compositions,...
We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-sized planets transiting L 98-59 (TOI-175, TIC 307210830) -- a bright M dwarf at distance 10.6 pc. Using Gaia-measured and broad-band photometry we find that host star is an M3 dwarf. Combined with TESS transits from sectors, corresponding stellar parameters yield planet radii ranging 0.8REarth to 1.6REarth. All have short orbital periods, 2.25 7.45 days outer pair just wide 2:1 period resonance....
We report the Transiting Exoplanet Survey Satellite ($TESS$) detection of a multi-planet system orbiting $V=10.9$ K0 dwarf TOI 125. find evidence for up to five planets, with varying confidence. Three high signal-to-noise transit signals correspond sub-Neptune-sized planets ($2.76$, $2.79$, and $2.94\ R_{\oplus}$), we statistically validate planetary nature two inner ($P_b = 4.65$ days, $P_c 9.15$ days). With only transits observed, outer object ($P_{.03} 19.98$ days) as ratio planet...
Abstract We present a photometric detection of the first brightness dips unique variable star KIC 8462852 since end Kepler space mission in 2013 May. Our regular surveillance started 2015 October, and sequence dipping began 2017 May continuing on through 2017, when was no longer visible from Earth. distinguish four main 1%–2.5% dips, named “ Elsie ,” Celeste Skara Brae Angkor which persist timescales several days to weeks. results so far are as follows: (i) there apparent changes stellar...
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...
Abstract Astronomers do not have a complete picture of the effects wide-binary companions (semimajor axes greater than 100 au) on formation and evolution exoplanets. We investigate these using new data from Gaia Early Data Release 3 Transiting Exoplanet Survey Satellite mission to characterize systems with transiting identify sample 67 exoplanet candidates (with well-determined, edge-on orbital inclinations) that reside in wide visual binary systems. derive limits parameters for measure...