A. Alqasim
A5063487442- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Spacecraft and Cryogenic Technologies
- Astrophysical Phenomena and Observations
- Statistics Education and Methodologies
- Galaxies: Formation, Evolution, Phenomena
- Scientific Measurement and Uncertainty Evaluation
- Astrophysics and Cosmic Phenomena
Astrobiology Center
2025
University College London
2022-2023
Abstract Eccentric giant planets are predicted to have acquired their eccentricity through two major mechanisms: the Kozai-Lidov effect or planet-planet scattering, but it is normally difficult separate mechanisms and determine true origin for a given system. In this work, we focus on sample of 92 transiting, long-period (TLGs) as part an distribution study planet population in order understand origin. Using archival high-contrast imaging observations, public stellar catalogs, precise Gaia...
HD 191939 (TOI-1339) is a nearby (d=54pc), bright (V=9mag), and inactive Sun-like star (G9 V) known to host multi-planet transiting system. Ground-based spectroscopic observations confirmed the planetary nature of three sub-Neptunes (HD b, c, d) originally detected by TESS were used measure masses for planets b c with 3$\sigma$ precision. These previous also reported discovery an additional Saturn-mass planet e) evidence further, very long-period companion f). Here, we report new...
ABSTRACT We report on the precise radial velocity follow-up of TOI-544 (HD 290498), a bright K star (V = 10.8), which hosts small transiting planet recently discovered by Transiting Exoplanet Survey Satellite (TESS). collected 122 high-resolution High Accuracy Radial Planet Searcher (HARPS) and HARPS-N spectra to spectroscopically confirm measure its mass. The nearly 3-yr baseline our allowed us unveil presence an additional, non-transiting, longer-period companion planet. derived radius...
We used TESS light curves and HARPS-N spectrograph radial velocity measurements to establish the physical properties of transiting exoplanet candidate found around star HD 20329 (TOI-4524). performed a joint fit time series measure mass, radius, orbital parameters candidate. confirm characterize 20329b, an ultra-short-period (USP) planet solar-type star. The host (HD 20329, $V = 8.74$ mag, $J 7.5$ mag) is characterized by its G5 spectral type with $\mathrm{M}_\star= 0.90 \pm 0.05$ M$_\odot$,...
We report the spectroscopic confirmation and fundamental properties of TOI-757 b, a mini-Neptune on 17.5-day orbit transiting bright star ($V = 9.7$ mag) discovered by TESS mission. acquired high-precision radial velocity measurements with HARPS, ESPRESSO, PFS spectrographs to confirm planet detection determine its mass. also space-borne transit photometry CHEOPS space telescope place stronger constraints radius, supported ground-based LCOGT photometry. WASP KELT were used help constrain...
ABSTRACT We report the spectroscopic confirmation and fundamental properties of TOI$-$757 b, a mini$-$Neptune on 17.5$-$d orbit transiting bright star ($V\, =\, 9.7$ mag) discovered by TESS mission. acquired high$-$precision radial velocity measurements with HARPS, ESPRESSO, PFS spectrographs to confirm planet detection determine its mass. also space$-$borne transit photometry CHEOPS space telescope place stronger constraints radius, supported ground$-$based LCOGT photometry. WASP KELT were...
Almost all massive galaxies today are understood to contain supermassive black holes (SMBH) at their centers. SMBHs grew by accreting material from surroundings, emitting X-rays as they did so. X-ray Luminosity Functions (XLFs) of Active Galactic Nuclei (AGN) have been extensively studied in order understand the AGN population's cosmological properties and evolution. We present a new fixed rest-frame method achieve more accurate study XLF evolution over cosmic time. Normally, XLFs...
Almost all massive galaxies today are understood to contain supermassive black holes (SMBH) at their centers. SMBHs grew by accreting material from surroundings, emitting X-rays as they did so. X-ray Luminosity Functions (XLFs) of Active Galactic Nuclei (AGN) have been extensively studied in order understand the AGN population's cosmological properties and evolution. We present a new fixed rest-frame method achieve more accurate study XLF evolution over cosmic time. Normally, XLFs...