Nick Choksi
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View article: The Resonant Remains of Broken Chains from Major and Minor Mergers
The Resonant Remains of Broken Chains from Major and Minor Mergers Open
TESS and Kepler have revealed that practically all close-in sub-Neptunes form in mean-motion resonant chains, most of which unravel on timescales of 100 Myr. Using N -body integrations, we study how planetary collisions from destabilized r…
View article: Spectral energy distributions of disc-embedded accreting protoplanets
Spectral energy distributions of disc-embedded accreting protoplanets Open
Many dozens of circumstellar discs show signatures of sculpting by planets. To help find these protoplanets by direct imaging, we compute their broadband spectral energy distributions, which overlap with the JWST and ALMA (Atacama Large Mi…
View article: The Prevalence of Resonance Among Young, Close-in Planets
The Prevalence of Resonance Among Young, Close-in Planets Open
Multiple planets undergoing disk migration may be captured into a chain of mean-motion resonances with the innermost planet parked near the disk’s inner edge. Subsequent dynamical evolution may disrupt these resonances, leading to the nonr…
View article: The Resonant Remains of Broken Chains from Major and Minor Mergers
The Resonant Remains of Broken Chains from Major and Minor Mergers Open
TESS and Kepler have revealed that practically all close-in sub-Neptunes form in mean-motion resonant chains, most of which unravel on timescales of 100 Myr. Using N-body integrations, we study how planetary collisions from destabilized re…
View article: The Prevalence of Resonance Among Young, Close-in Planets
The Prevalence of Resonance Among Young, Close-in Planets Open
Multiple planets undergoing disk migration may be captured into a chain of mean-motion resonances with the innermost planet parked near the disk's inner edge. Subsequent dynamical evolution may disrupt these resonances, leading to the non-…
View article: Spectral Energy Distributions of Disc-Embedded Accreting Protoplanets
Spectral Energy Distributions of Disc-Embedded Accreting Protoplanets Open
Many dozens of circumstellar discs show signatures of sculpting by planets. To help find these protoplanets by direct imaging, we compute their broadband spectral energy distributions, which overlap with the JWST (James Webb Space Telescop…
View article: The maximum accretion rate of a protoplanet: how fast can runaway be?
The maximum accretion rate of a protoplanet: how fast can runaway be? Open
The hunt is on for dozens of protoplanets hypothesised to reside in protoplanetary discs with imaged gaps. How bright these planets are, and what they will grow to become, depend on their accretion rates, which may be in the runaway regime…
View article: Exciting the TTV Phases of Resonant Sub-Neptunes
Exciting the TTV Phases of Resonant Sub-Neptunes Open
There are excesses of sub-Neptunes just wide of period commensurabilities like the 3:2 and 2:1, and corresponding deficits narrow of them. Any theory that explains this period ratio structure must also explain the strong transit timing var…
View article: An Implementation of Stochastic Forces for the N-body Code REBOUND
An Implementation of Stochastic Forces for the N-body Code REBOUND Open
We describe the implementation of a new module which can be used to simulate physical systems in which the motion of particles is affected by stochastic forces. Such forces are expected to be present in turbulent circumstellar disks or rem…
View article: The Lick Observatory Supernova Search follow-up program: photometry data release of 70 SESNe
The Lick Observatory Supernova Search follow-up program: photometry data release of 70 SESNe Open
We present BVRI and unfiltered (Clear) light curves of 70 stripped-envelope supernovae (SESNe), observed between 2003 and 2020, from the Lick Observatory Supernova Search follow-up program. Our SESN sample consists of 19 spectroscopically …
View article: Testing planet formation from the ultraviolet to the millimeter
Testing planet formation from the ultraviolet to the millimeter Open
Gaps imaged in protoplanetary discs are suspected to be opened by planets. We compute the present-day mass accretion rates $\dot{M}_{\rm p}$ of seven hypothesized gap-embedded planets, plus the two confirmed planets in the PDS 70 disc. The…
View article: On the initial mass–radius relation of stellar clusters
On the initial mass–radius relation of stellar clusters Open
Young stellar clusters across nearly five orders of magnitude in mass appear to follow a power-law mass–radius relationship (MRR), $R_{\star }\propto M_{\star }^{\alpha }$, with α ≈ 0.2–0.33. We develop a simple analytic model for the clus…
View article: Chondrules from high-velocity collisions: thermal histories and the agglomeration problem
Chondrules from high-velocity collisions: thermal histories and the agglomeration problem Open
We assess whether chondrules, once-molten mm-sized spheres filling the oldest meteorites, could have formed from super-km s−1 collisions between planetesimals in the solar nebula. High-velocity collisions release hot and dense clouds of si…
View article: Chondrules as fallout from vaporizing impacts in the solar nebula
Chondrules as fallout from vaporizing impacts in the solar nebula Open
We consider how chondrules, once-molten mm-sized spheres filling the oldest meteorites, may have formed as the thermally processed fallout from planetesimal collisions in the primordial solar nebula. We focus on the cloud of hot and dense …
View article: Sub-Neptune formation: the view from resonant planets
Sub-Neptune formation: the view from resonant planets Open
The orbital period ratios of neighbouring sub-Neptunes are distributed asymmetrically near first-order resonances. There are deficits of systems – ‘troughs’ in the period ratio histogram – just short of commensurability, and excesses – ‘pe…
View article: Lick Observatory Supernova Search follow-up program: photometry data release of 93 Type Ia supernovae
Lick Observatory Supernova Search follow-up program: photometry data release of 93 Type Ia supernovae Open
We present BVRI and unfiltered light curves of 93 Type Ia supernovae (SNe Ia) from the Lick Observatory Supernova Search (LOSS) follow-up program conducted between 2005 and 2018. Our sample consists of 78 spectroscopically normal SNe Ia, w…
View article: Origins of scaling relations of globular cluster systems
Origins of scaling relations of globular cluster systems Open
Globular cluster (GC) systems demonstrate tight scaling relations with the properties of their host galaxies. In previous work, we developed an analytic model for GC formation in a cosmological context that matches nearly all of these obse…
View article: Formation of globular cluster systems – II. Impact of the cut-off of the cluster initial mass function
Formation of globular cluster systems – II. Impact of the cut-off of the cluster initial mass function Open
Observations of young star clusters reveal that the high-mass end of the\ncluster initial mass function (CIMF) deviates from a pure power-law and instead\ntruncates exponentially. We investigate the effects of this truncation on the\nforma…
View article: The formation and hierarchical assembly of globular cluster populations
The formation and hierarchical assembly of globular cluster populations Open
We use a semi-analytic model for globular cluster (GC) formation built on dark matter merger trees to explore the relative role of formation physics and hierarchical assembly in determining the properties of GC populations. Many previous w…
View article: Formation of globular cluster systems: from dwarf galaxies to giants
Formation of globular cluster systems: from dwarf galaxies to giants Open
Globular cluster (GC) systems around galaxies of a vast mass range show\nremarkably simple scaling relations. The combined mass of all GCs is a constant\nfraction of the total galaxy mass and the mean metallicity and metallicity\ndispersio…
View article: Recoiling supermassive black hole escape velocities from dark matter haloes
Recoiling supermassive black hole escape velocities from dark matter haloes Open
We simulate recoiling black hole trajectories from $z=20$ to $z=0$ in dark\nmatter halos, quantifying how parameter choices affect escape velocities. These\nchoices include the strength of dynamical friction, the presence of stars and\ngas…