Zahra Essack
A5038444269- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Spacecraft and Cryogenic Technologies
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- High-pressure geophysics and materials
- Calibration and Measurement Techniques
- Spectroscopy and Laser Applications
- Planetary Science and Exploration
- Advanced Chemical Physics Studies
Massachusetts Institute of Technology
2018-2024
University of New Mexico
2023-2024
University of Geneva
2024
Planetary Science Institute
2019-2023
Kavli Institute for Particle Astrophysics and Cosmology
2022
American Institute of Aeronautics and Astronautics
2020
We present 2,241 exoplanet candidates identified with data from the Transiting Exoplanet Survey Satellite (TESS) during its two-year prime mission. list these in TESS Objects of Interest (TOI) Catalog, which includes both new planet found by and previously-known planets recovered observations. describe process used to identify TOIs investigate characteristics candidates, discuss some notable discoveries. The TOI Catalog an unprecedented number small around nearby bright stars, are...
Abstract We present the discovery and validation of a three-planet system orbiting nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). lies in TESS continuous viewing zone Southern Ecliptic Hemisphere; observations spanning 11 sectors reveal three planets with radii ranging from 1 R ⊕ to 2.6 orbital periods 9.98 37.43 days. Ground-based follow-up combined diagnostic vetting tests enables us rule out common astrophysical false-positive scenarios validate planets. The outermost planet, d,...
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...
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 We carry out a phase-curve analysis of the KELT-9 system using photometric observations from NASA’s Transiting Exoplanet Survey Satellite (TESS). The measured secondary eclipse depth and peak-to-peak atmospheric brightness modulation are <?CDATA ${650}_{-15}^{+14}$?> 566 ± 16 ppm, respectively. planet’s variation reaches maximum 31 5 minutes before midpoint eclipse, indicating 5.°2 0.°9 eastward shift in dayside hot spot substellar point. also detect stellar pulsations on with...
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....
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...
Abstract Characterizing the bulk compositions of transiting exoplanets within M dwarf radius valley offers a unique means to establish whether emerges from an atmospheric mass-loss process or is imprinted by planet formation itself. We present confirmation such orbiting early-M ( T mag = 11.0294 ± 0.0074, s 0.513 0.012 ⊙ , R 0.515 0.015 and eff 3690 50 K): TOI-1695 b P 3.13 days <?CDATA ${R}_{p}={1.90}_{-0.14}^{+0.16}\ {R}_{\oplus }$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
We present the discovery of two exoplanets transiting TOI-836 (TIC 440887364) using data from TESS Sector 11 and 38. is a bright ($T = 8.5$ mag), high proper motion ($\sim\,200$ mas yr$^{-1}$), low metallicity ([Fe/H]$\approx\,-0.28$) K-dwarf with mass $0.68\pm0.05$ M$_{\odot}$ radius $0.67\pm0.01$ R$_{\odot}$. obtain photometric follow-up observations variety facilities, we use these data-sets to determine that inner planet, b, $1.70\pm0.07$ R$_{\oplus}$ super-Earth in 3.82 day orbit,...
We present the confirmation and characterisation of GJ 3473 b (G 50--16, TOI-488.01), a hot Earth-sized planet orbiting an M4 dwarf star, whose transiting signal ($P=1.1980035\pm0.0000018\mathrm{\,d}$) was first detected by Transiting Exoplanet Survey Satellite (TESS). Through joint modelling follow-up radial velocity observations with CARMENES, IRD, HARPS together extensive ground-based photometric LCOGT, MuSCAT, MuSCAT2, we determined precise planetary mass, $M_b =...
We report the discovery and characterization of three new transiting giant planets orbiting TOI-6628, TOI-3837, TOI-5027 one warm sub-Saturn TOI-2328, whose transits events were detected in light curves Transiting Exoplanet Survey Satellite (TESS) space mission. By combining TESS with ground-based photometric spectroscopic follow-up observations, we confirm planetary nature observed radial velocity variations. TOI-6628 b has a mass 0.74±0.06 M_ radius 0.98 -0.05 R_J orbits metal-rich star...
Measuring the properties of planets younger than about 50 Myr helps to test different planetary formation and evolution models. NASA's Transiting Exoplanet Survey Satellite (TESS) has observed nearly entire sky, including a wide range star-forming regions young stellar clusters, expanding our census newborn planet population. In this work, we present discovery TIC 88785435 system located in Upper-Centaurus Lupus (UCL) region Scorpius-Centaurus OB association (Sco-Cen) preliminary survey...
We report the discovery and characterization of TOI-2005b, a warm Jupiter on an eccentric (e~0.59), 17.3-day orbit around V_mag = 9.867 rapidly rotating F-star. The object was detected as candidate by TESS planetary nature TOI-2005b then confirmed via series ground-based photometric, spectroscopic, diffraction-limited imaging observations. planet found to reside in low sky-projected stellar obliquity (lambda 4.8 degrees) transit spectroscopic observation using Magellan MIKE...
Abstract We report the discovery of TOI-172 b from Transiting Exoplanet Survey Satellite ( TESS ) mission, a massive hot Jupiter transiting slightly evolved G star with 9.48-day orbital period. This is first planet to be confirmed analysis only full frame images, because host was not chosen as two-minute cadence target. From global photometry and follow-up observations carried out by Follow-up Observing Program Working Group, (TIC 29857954) an effective temperature T eff = 5645 ± 50 K, mass...
Abstract Hot super-Earths are exoplanets with short orbital periods (<10 days), heated by their host stars to temperatures high enough for rocky surfaces become molten. A few hot exhibit geometric albedos (>0.4) in the Kepler band (420–900 nm). We motivated determine whether reflection from molten lava and quenched glasses (a product of rapidly cooled lava) on contribute observationally inferred albedos. experimentally measure rough- smooth-textured both basalt feldspar melts. For...
Abstract We present the results of a uniform search for additional planets around all stars with confirmed hot Jupiters observed by Transiting Exoplanet Survey Satellite (TESS) in its Cycle 1 survey southern ecliptic hemisphere. Our comprises 184 total planetary systems R p > 8 ⊕ and orbital period <10 days. The Transit Least Squares algorithm was utilized to periodic signals that may have been missed other planet pipelines. While we recovered 169 these Jupiters, our yielded no new...
The James Webb Space Telescope (JWST) will be able to probe the atmospheres and surface properties of hot, terrestrial planets via emission spectroscopy. We identify 18 potentially planet candidates detected by Transiting Exoplanet Survey Satellite (TESS) that would make ideal targets for these observations. These cover a broad range radii ($R_{\rm p} \sim 0.6 - 2.0 R_\oplus$) orbit stars various magnitudes ($K_s = 5.78 10.78$, $V 8.4 15.69$) effective temperatures ($T_{\rm eff }\sim 3000...
Populating the exoplanet mass-radius diagram in order to identify underlying relationship that governs planet composition is driving an interdisciplinary effort within community. The discovery of hot super-Earths - a high temperature, short-period subset super-Earth population has presented many unresolved questions concerning formation, evolution, and rocky planets. We report transiting, ultra-short period orbiting TOI-1075 (TIC 351601843), nearby ($d$ = 61.4 pc) late K-/early M-dwarf star,...
ABSTRACT We report the discovery of two warm sub-Neptunes transiting bright (G = 9.5 mag) K-dwarf HD 15906 (TOI 461, TIC 4646810). This star was observed by Transiting Exoplanet Survey Satellite (TESS) in sectors 4 and 31, revealing small planets. The inner planet, b, detected with an unambiguous period but outer c, showed only transits separated ∼ 734 d, leading to 36 possible values its period. performed follow-up observations CHaracterising ExOPlanet (CHEOPS) confirm true c improve radius...
ABSTRACT We report on the discovery of Gliese 12 b, nearest transiting temperate, Earth-sized planet found to date. is a bright (V = 12.6 mag, K 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from Solar system with one lowest stellar activity levels known for M-dwarfs. A candidate was detected by TESS based 3 transits in sectors 42, 43, and 57, an ambiguity orbital period due observational gaps. performed follow-up transit observations CHEOPS ground-based photometry...
ABSTRACT Short-period gas giant planets have been shown to be significantly rarer for host stars less massive than the Sun. We report discovery of two transiting – TOI-2379 b and TOI-2384 with low-mass (early M) stars. Both were detected using Transiting Exoplanet Survey Satellite photometry both transit signal was validated ground-based photometric facilities. confirm planetary nature these companions measure their masses radial velocity observations. find that has an orbital period 5.469 d...
Abstract Hot Jupiters—short-period giant planets—were the first extrasolar planets to be discovered, but many questions about their origin remain. NASA’s Transiting Exoplanet Survey Satellite (TESS), an all-sky search for transiting planets, presents opportunity address these by constructing a uniform sample of hot Jupiters demographic study through new detections and unifying work previous ground-based transit surveys. As results effort build this large we report here discovery 10...
One of the main scientific goals TESS mission is discovery transiting small planets around closest and brightest stars in sky. Here, using data from CARMENES, MAROON-X, HIRES spectrographs together with TESS, we report mass determination aplanetary system M1.5 V star GJ 806 (TOI-4481). a bright ( ≈ 10.8mag, J 7.3 mag) nearby d = 12 pc) M dwarf that hosts at least two planets. The innermost planet, b, has an ultra-short orbital period 0.93 d, radius 1.331 ± 0.023 R ⊕ , 1.90 0.17 mean density...
We report the discovery and characterisation of a super-Earth sub-Neptune transiting bright ( K = 8.8), quiet, nearby (37 pc) M3V dwarf TOI-1266. validate planetary nature TOI-1266 b c using four sectors TESS photometry data from newly-commissioned 1-m SAINT-EX telescope located in San Pedro Mártir (México). also include additional ground-based follow-up as well high-resolution spectroscopy high-angular imaging observations. The inner, larger planet has radius R 2.37 −0.12 +0.16 ⊕ an orbital...
We report the confirmation of three exoplanets transiting TOI-4010 (TIC-352682207), a metal-rich K dwarf observed by TESS in Sectors 24, 25, 52, and 58. confirm these planets with HARPS-N radial velocity observations measure their masses 8 - 12% precision. b is sub-Neptune ($P = 1.3$ days, $R_{p} 3.02_{-0.08}^{+0.08}~R_{\oplus}$, $M_{p} 11.00_{-1.27}^{+1.29}~M_{\oplus}$) hot Neptune desert, one few such known companions. Meanwhile, c 5.4$ 5.93_{-0.12}^{+0.11}~R_{\oplus}$,...