A5073940963- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Planetary Science and Exploration
- Solar and Space Plasma Dynamics
- Isotope Analysis in Ecology
- Scientific Research and Discoveries
- Geomagnetism and Paleomagnetism Studies
- High-pressure geophysics and materials
- History and Developments in Astronomy
- Space Exploration and Technology
- Astrophysical Phenomena and Observations
- Advanced NMR Techniques and Applications
- Spaceflight effects on biology
- Astronomical Observations and Instrumentation
- SAS software applications and methods
- Ionosphere and magnetosphere dynamics
- Advanced MRI Techniques and Applications
- Medical Imaging Techniques and Applications
- Geophysics and Gravity Measurements
- Scientific Computing and Data Management
- Mechanics and Biomechanics Studies
- Atmospheric Ozone and Climate
Massachusetts Institute of Technology
2022-2024
Princeton University
2020-2022
Yale University
2017-2021
University of California, Santa Cruz
2016
The widespread prevalence of close-in, nearly coplanar super-Earth- and sub-Neptune-sized planets in multiple-planet systems was one the most surprising results from Kepler mission. By studying a uniform sample "multis" with mass measurements transit timing variations (TTVs), we show that given planetary system tends to harbor characteristic type planet. That is, have both masses radii are far more similar than if were assembled randomly population. This finding has two important...
Abstract The warm Neptune GJ 3470b transits a nearby ( d = 29 pc) bright slowly rotating M1.5-dwarf star. Using spectroscopic observations during two with the newly commissioned NEID spectrometer on WIYN 3.5 m Telescope at Kitt Peak Observatory, we model classical Rossiter–McLaughlin effect, yielding sky-projected obliquity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>λ</mml:mi> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>98</mml:mn>...
Abstract About a dozen exoplanetary systems have been discovered with three or more planets participating in sequence of mean-motion resonances. The unique and complex architectures these so-called “resonant chains” motivate efforts to characterize their holistically. In this work, we perform comprehensive exploration the spin-axis dynamics resonant chains. Planetary spin states are closely linked atmospheric habitability thus especially relevant chains like TRAPPIST-1, which hosts several...
Abstract The two planets of the HAT-P-11 system represent fascinating dynamical puzzles due to their significant eccentricities and orbital misalignments. In particular, b is in a close-in orbit which tides should have circularized well within age system. Here we propose two-step process that can reproduce all intriguing aspects We first invoke planet–planet scattering generate mutual inclinations between planets. then this misalignment initiated von-Zeipel-Lidov-Kozai cycles...
Abstract The orbits of short-period exoplanets are sculpted by tidal dissipation. However, the mechanisms and associated efficiencies these interactions poorly constrained. We present robust constraints on quality factors exoplanetary host stars through usage a novel empirical technique. method is based analyzing structures in population-level distribution decay times, defined as time remaining before planet spirals into its star due to stellar tides. Using simple synthetic population...
The standard model for eruptive flares has in the past few years been extended to 3D. It predicts typical J-shaped photospheric footprints of coronal current layer, forming at similar locations as Quasi-Separatrix Layers (QSLs). Such a morphology is also found flare ribbons observed EUV band, well non-linear force-free field (NLFFF) magnetic extrapolations and models. We study evolution traces density ribbons, both obtained with SDO instruments. investigate during 6 September 2011 X-class...
Small, rocky planets have been found orbiting in extreme proximity to their host stars, sometimes down only $\sim 2$ stellar radii. These ultra-short-period (USPs) likely did not form present-day orbits, but rather migrated from larger initial separations. While tides are the probable cause of this migration, tidal source has remained uncertain. Here we introduce planetary obliquity as a natural pathway for production USPs within close-in multi-planet systems. The crucial idea is that...
We place the first constraints on obliquity of a planetary-mass companion (PMC) outside Solar System. Our target is directly imaged system 2MASS J01225093-2439505 (2M0122), which consists 120 Myr 0.4 M_sun star hosting 12-27 M_J at 50 AU. constrain all three system's angular momentum vectors: how spin axis, stellar and orbit normal are inclined relative to our line sight. To accomplish this, we measure projected rotation rates (vsini) for both using new near-infrared high-resolution spectra...
Abstract Multiple planets undergoing disk migration may be captured into a chain of mean-motion resonances with the innermost planet parked near disk’s inner edge. Subsequent dynamical evolution disrupt these resonances, leading to nonresonant configurations typically observed among Kepler that are Gyr old. In this scenario, resonant expected more common in younger systems. This prediction can now tested, thanks recent discoveries young planets, particular those stellar clusters, by NASA’s...
We report the first confirmation of a hot Jupiter discovered by Transiting Exoplanet Survey Satellite (TESS) mission: HD 202772A b. The transit signal was detected in data from TESS Sector 1, and confirmed to be planetary origin through radial-velocity measurements. b is orbiting mildly evolved star with period 3.3 days. With an apparent magnitude V = 8.3, among brightest known host Jupiter. Based on 27days photometry, radial velocity CHIRON HARPS spectrographs, planet has mass 1.008+/-0.074...
We report the discovery and dynamical analysis of 2015 BP$_{519}$, an extreme Trans-Neptunian Object detected by Dark Energy Survey at a heliocentric distance 55 AU absolute magnitude Hr= 4.3. The current orbit, determined from 1110-day observational arc, has semi-major axis $a\approx$ 450 AU, eccentricity $e\approx$ 0.92 inclination $i\approx$ 54 degrees. With these orbital elements, BP$_{519}$ is most TNO discovered to date, as quantified reduced Kozai action, which conserved quantity...
We have introduced self-consistent spin, tidal and dynamical equations of motion into REBOUNDx, a library additional effects for the popular N-body integrator REBOUND. The used are derived from constant time lag approximation to equilibrium tide model friction. These will allow study variety systems where full picture cannot be encapsulated by point particle dynamics. provide several test cases benchmark code's performance against analytic predictions. open-source code is available in most...
Abstract Giant exoplanets orbiting close to their host stars are unlikely have formed in present configurations 1 . These ‘hot Jupiter’ planets instead thought migrated inward from beyond the ice line and several viable migration channels been proposed, including eccentricity excitation through angular-momentum exchange with a third body followed by tidally driven orbital circularization 2,3 The discovery of extremely eccentric ( e = 0.93) giant exoplanet HD 80606 b (ref. 4 ) provided...
The tilt of a planet's spin axis off its orbital ("obliquity") is basic physical characteristic that plays central role in determining the global circulation and energy redistribution. Moreover, recent studies have also highlighted importance obliquities sculpting not only features exoplanets but their architectures. It therefore key to identify characterize dominant processes excitation non-zero axial tilts. Here we highlight simple mechanism operates early on likely fundamental for many...
While the Solar System contains no planets between sizes of Uranus and Saturn, our current exoplanet census includes several dozen such with well-measured masses radii. These sub-Saturns exhibit a diversity bulk densities, ranging from ~$0.1-3\ \rm{g\ cm}^{-3}$. When modeled simply as hydrogen/helium envelopes atop rocky cores, this in densities translates to planetary envelope fractions, $f_\rm{env}=M_\rm{env}/M_p$ ~$10\%$ ~$50\%$. Planets $f_\rm{env}\sim50\%$ pose challenge traditional...
Early analyses of exoplanet statistics from the Kepler Mission revealed that a model population multiple-planet systems with low mutual inclinations (${\sim1^{\circ}-2^{\circ}}$) adequately describes multiple-transiting but underpredicts number single-transiting systems. This so-called "Kepler dichotomy" signals existence sub-population multi-planet possessing larger inclinations. However, details these remain uncertain. In this work, we derive constraints on intrinsic inclination...
A systematic, population-level discrepancy exists between the densities of exoplanets whose masses have been measured with transit timing variations (TTVs) versus those radial velocities (RVs). Since TTV planets are predominantly nearly resonant, it is still unclear whether attributed to detection biases or astrophysical differences resonant and non planet populations. We defined a controlled, unbiased sample 36 sub-Neptunes characterised by Kepler, TESS, HARPS, ESPRESSO. found that their...
The optical, full-phase photometric variations of a short-period planet provide unique view the planet's atmospheric composition and dynamics. number planets with optical phase curve detections, however, is currently too small to study them as an aggregate population, motivating extension search non-transiting planets. Here we present algorithm for detection non-transiting, giant in Kepler field. procedure uses curves themselves evidence planets' existence. We employ supervised learning...
ABSTRACT We outline a photometric method for detecting the presence of non-transiting short-period giant planet in planetary system harboring one or more longer-period transiting planets. Within prospective type that we consider, hot Jupiter on an interior orbit inclined to line sight signals its through approximately sinusoidal full-phase variations stellar light curve, correlated with astrometrically induced transit timing exterior Systems containing along low-mass outer planets orbits are...
Recent analyses have revealed a mystery. The orbital period of the highly inflated hot Jupiter, WASP-12b, is decreasing rapidly. rate inspiral, however, too fast to be explained by either eccentricity tides or equilibrium stellar tides. While dynamical are possible, they require subgiant structure for star, whereas models point toward main sequence host. Here, we show that these hitherto irreconcilable observations might planetary obliquity if planet b's spin vector trapped in high-obliquity...
Abstract The planets within compact multiplanet systems tend to have similar sizes, masses, and orbital period ratios, like “peas in a pod.” This pattern was detected when considering with radii between 1 4 R ⊕ . However, these same show bimodal radius distribution, few 1.5 2 smaller “super-Earths” are consistent being stripped rocky cores, while the larger “sub-Neptunes” likely gaseous H/He envelopes. Given distinct structures, it is worthwhile test for intra-system uniformity separately...
Machine learning (ML) methods can expand our ability to construct, and draw insight from large datasets. Despite the increasing volume of planetary observations, field has seen few applications ML in comparison other sciences. To support these methods, we propose ten recommendations for bolstering a data-rich future science.
Abstract Although the architectures of compact multiple-planet systems are well characterized, there has been little examination their “outer edges,” or locations outermost planets. Here we present evidence that observed high-multiplicity Kepler truncate at smaller orbital periods than can be explained by geometric and detection biases alone. To show this, considered existence hypothetical planets orbiting beyond transiting with properties dictated “peas-in-a-pod” patterns intrasystem radius...