Dynamical Evolution of Young Embedded Clusters: A Parameter Space Survey (2009)
Proszkow, Eva-Marie, Adams, Fred C.
This paper investigates the dynamical evolution of embedded stellar clusters from the protocluster stage, through the embedded star-forming phase, and out to ages of 10 Myr -- after the gas has been...
Migration of Extrasolar Planets: Effects from X-Wind Accretion Disks (2009)
Adams, Fred C., Cai, Mike J., Lizano, Susana
Magnetic fields are dragged in from the interstellar medium during the gravitational collapse that forms star/disk systems. Consideration of mean field magnetohydrodynamics (MHD) in these disks shows...
HILL’S EQUATION WITH RANDOM FORCING TERMS (2009)
Fred C. Adams, Anthony M. Bloch
Motivated by a class of orbit problems in astrophysics, this paper considers solutions to Hill’s equation with forcing strength parameters that vary from cycle to cycle. The results are generalized...
General Analysis of Type I Planetary Migration with Stochastic Perturbations (2009)
Adams, Fred C., Bloch, Anthony M.
This paper presents a generalized treatment of Type I planetary migration in the presence of stochastic perturbations. In many planet-forming disks, the Type I migration mechanism, driven by...
Hill's Equation with Random Forcing Parameters: The Limit of Delta Function Barriers (2009)
Adams, Fred C., Bloch, Anthony M.
This paper considers random Hill's equations in the limit where the periodic forcing function becomes a Dirac delta function. For this class of equations, the forcing strength $q_k$, the oscillation...
Kinematic Signatures of Subvirial Initial Conditions in Young Clusters (2009)
Proszkow, Eva-Marie, Adams, Fred C., Hartmann, Lee W., Tobin, John J.
Motivated by kinematic observations of young embedded clusters, this paper explores possible kinematic signatures produced by asphericity and departures from initial virial equilibrium in these...
Low Mass Companions for Five Solar-Type Stars from the Magellan Planet Search Program (2008)
Minniti, Dante, Butler, R. Paul, Lopez-Morales, Mercedes, Shectman, Stephen A., Adams, Fred C., Arriagada, Pamela, ...
We report low mass companions orbiting five Solar-type stars that have emerged from the Magellan precision Doppler velocity survey, with minimum (Msini) masses ranging from 1.2 to 25 Mjup. These...
Lecoanet, Daniel, Adams, Fred C., Bloch, Anthony M.
This paper continues previous work on the effects of turbulence on mean motion resonances in extrasolar planetary systems. Turbulence is expected to arise in the disks that form planets, and these...
Two Jupiter-Mass Planets Orbiting HD 154672 and HD 205739 (2008)
Lopez-Morales, Mercedes, Butler, R. Paul, Fischer, Debra A., Minniti, Dante, Shectman, Stephen A., Takeda, Genya, ...
We report the detection of the first two planets from the N2K Doppler planet search program at the Magellan telescopes. The first planet has a mass of M sin i = 4.96 M_Jup and is orbiting the G3 IV...
Ketchum, Jacob A., Adams, Fred C.
Motivated by the possibility that the fundamental ``constants'' of nature could vary with time, this paper considers the long term evolution of white dwarf stars under the combined action of proton...
Stars In Other Universes: Stellar structure with different fundamental constants (2008)
Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the existence...
Turbulence in Extrasolar Planetary Systems Implies that Mean Motion Resonances are Rare (2008)
Adams, Fred C., Laughlin, Gregory, Bloch, Anthony M.
This paper considers the effects of turbulence on mean motion resonances in extrasolar planetary systems and predicts that systems rarely survive in a resonant configuration. A growing number of...
Mersini-Houghton, Laura, Adams, Fred C
"This paper investigates anthropic bounds on the vacuum energy L by considering alternate starting assumptions. We first consider the possibility of cosmic observers existing at any random time...
The effects of young embedded groups and clusters on forming solar systems (2008)
"Most stars--and hence most solar systems--form within groups or clusters. This contribution discusses how these star forming environments affect the planetary systems forming within them. The...
Stars in other universes: stellar structure with different fundamental constants (2008)
"Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the...
The Eccentric Frame Decomposition of Central Force Fields (2007)
Maruskin, Jared M., Scheeres, Daniel J., Adams, Fred C., Bloch, Anthony M.
The rosette-shaped motion of a particle in a central force field is known to be classically solvable by quadratures. We present a new approach of describing and characterizing such motion based on...
Gregory Laughlin, Fred C. Adams
A number of recently discovered extrasolar planet candidates have surprisingly small orbits, which may indicate that considerable orbital migration takes place in protoplanetary systems. A natural...
Inflation without inflaton(s) (2007)
Watson, Scott, Perry, Malcolm J, Kane, Gordon L, Adams, Fred C
We propose a model for early universe cosmology without the need for fundamental scalar fields. Cosmic acceleration and phenomenologically viable reheating of the universe result from a series of...
Ambipolar Diffusion in Molecular Cloud Cores and the Gravomagneto Catastrophe (2007)
This paper re-examines the problem of ambipolar diffusion as a mechanism for the production and runaway evolution of centrally condensed molecular cloud cores, a process that has been termed the...
Orbital Instabilities in a Triaxial Cusp Potential (2007)
Adams, Fred C., Bloch, Anthony M., Butler, Suzanne C., Druce, Jeffrey M., Ketchum, Jacob A.
This paper constructs an analytic form for a triaxial potential that describes the dynamics of a wide variety of astrophysical systems, including the inner portions of dark matter halos, the central...
Eccentricity evolution of giant planet orbits due to circumstellar disk torques (2007)
Moorhead, Althea V., Adams, Fred C.
The extrasolar planets discovered to date possess unexpected orbital elements. Most orbit their host stars with larger eccentricities and smaller semi-major axes than similarly sized planets in our...
Role of Dynamical Research in the Detection and Characterization of Exoplanets (2007)
Ford, Eric B., Adams, Fred C., Armitage, Phil, Gaudi, B. Scott, Malhotra, Renu, Holman, Mathew J., ...
(Abridged) The discovery of extrasolar planetary systems revealed an unexpected diversity of planetary systems that has revolutionized planet formation theory. A strong program of theoretical...
Terrestrial Planet Formation Around Individual Stars Within Binary Star Systems (2007)
Quintana, Elisa V., Adams, Fred C., Lissauer, Jack J., Chambers, John E.
We calculate herein the late stages of terrestrial planet accumulation around a solar type star that has a binary companion with semimajor axis larger than the terrestrial planet region. We perform...
The Asymptotic Form of Cosmic Structure: Small Scale Power and Accretion History (2006)
Busha, Michael T., Evrard, August E., Adams, Fred C.
We explore the effects of small scale structure on the formation and equilibrium of dark matter halos in a universe dominated by vacuum energy. We present the results of a suite of four N-body...
Relativistic Effects in Extrasolar Planetary Systems (2006)
Adams, Fred C., Laughlin, Gregory
This paper considers general relativistic (GR) effects in currently observed extrasolar planetary systems. Although GR corrections are small, they can compete with secular interactions in these...
Inflation without Inflaton(s) (2006)
Watson, Scott, Perry, Malcolm J., Kane, Gordon L., Adams, Fred C.
We propose a model for early universe cosmology without the need for fundamental scalar fields. Cosmic acceleration and phenomenologically viable reheating of the universe results from a series of...
Baryonic Collapse within Dark Matter Halos and the Formation of Gaseous Galactic Disks (2006)
Adams, Fred C., Bloch, Anthony M.
This paper constructs an analytic framework for calculating the assembly of galactic disks from the collapse of gas within dark matter halos, with the goal of determining the surface density...
Effects of Secular Interactions in Extrasolar Planetary Systems (2006)
Adams, Fred C., Laughlin, Gregory
This paper studies the effects of dynamical interactions among the planets in observed extrasolar planetary systems, including hypothetical additional bodies, with a focus on secular perturbations....
Long Term Evolution of Close Planets Including the Effects of Secular Interactions (2006)
Adams, Fred C., Laughlin, Gregory
This paper studies the long term evolution of planetary systems containing short-period planets, including the effects of tidal circularization, secular excitation of eccentricity by companion...
Terrestrial Planet Formation in Binary Star Systems (2006)
Jack J. Lissauer, Elisa V. Quintana, John E. Chambers, Fred C. Adams, Martin J. Duncan
Terrestrial Planet Formation in Binary Star Systems
Red Dwarfs and the End of the Main Sequence (2006)
Fred C. Adams, Gregory Laughlin
Red Dwarfs and the End of the Main Sequence
Stojkovic, Dejan, Starkman, Glenn D., Adams, Fred C.
It has been claimed recently that the black hole information-loss paradox has been resolved: the evolution of quantum states in the presence of a black hole is unitary and information preserving. We...
Adams, Fred C., Proszkow, Eva M., Fatuzzo, Marco, Myers, Philip C.
This paper studies the dynamical evolution of young stellar clusters with $N$ = 100 - 1000 members. We use N-body simulations to explore how evolution depends on system size $N$ and the initial...
Lithopanspermia in Star-Forming Clusters (2005)
Adams, Fred C., Spergel, David N.
This paper considers the lithopanspermia hypothesis in star-forming groups and clusters, where the chances of biological material spreading from one solar system to another is greatly enhanced...
Giant Planet Migration through the Action of Disk Torques and Planet Scattering (2005)
Moorhead, Althea V., Adams, Fred C.
This paper presents a parametric study of giant planet migration through the combined action of disk torques and planet-planet scattering. The torques exerted on planets during Type II migration in...
Lithopanspermia in Star Forming Clusters (2005)
Adams, Fred C., Spergel, David N.
This paper considers the lithopanspermia hypothesis in star forming groups and clusters, where the chances of biological material spreading from one solar system to another is greatly enhanced...
Orbits in Extended Mass Distributions: General Results and the Spirographic Approximation (2005)
Adams, Fred C., Bloch, Anthony M.
This paper explores orbits in extended mass distributions and develops an analytic approximation scheme based on epicycloids (spirograph patterns). We focus on the Hernquist potential which provides...
Adams, Fred C., Freese, Katherine
We present an inflationary universe model which utilizes two coupled real scalar fields. The inflation field $\phi$ experiences a first order phase transition and its potential dominates the energy...
ORBITS IN EXTENDED MASS DISTRIBUTIONS: GENERAL RESULTS AND THE SPIROGRAPHIC APPROXIMATION (2005)
Fred C. Adams, Anthony M. Bloch
This paper explores orbits in extended mass distributions and develops an analytic approximation scheme based on epicycloids (spirograph patterns). We focus on the Hernquist potential 1/(1 þ), which...
The Ultimate Halo Mass in a LCDM Universe (2004)
Busha, Michael T., Evrard, August E., Adams, Fred C., Wechsler, Risa H.
In the far future of an accelerating LCDM cosmology, the cosmic web of large-scale structure consists of a set of increasingly isolated halos in dynamical equilibrium. We examine the approach of...
Core-Accretion Model Predicts Few Jovian-Mass Planets Orbiting Red Dwarfs (2004)
Laughlin, Gregory, Bodenheimer, Peter, Adams, Fred C.
The favored theoretical explanation for giant planet formation -- in both our solar system and others -- is the core accretion model (although it still has some serious difficulties). In this...
Photoevaporation of Circumstellar Disks due to External FUV Radiation in Stellar Aggregates (2004)
Adams, Fred C., Hollenbach, David, Laughlin, Gregory, Gorti, Uma
When stars form in small groups (N = 100 - 500 members), their circumstellar disks are exposed to little EUV radiation but a great deal of FUV radiation from massive stars in the group. This paper...
Possible Limits on Photon Propagation from Quantum Gravity and Space-time Foam (2004)
Mbonye, Manasse, Adams, Fred C.
Many quantum gravity theories imply that the vacuum is filled with virtual black holes. This paper explores the process in which high energy photons interact with virtual black holes and decay into...
Red Dwarfs and the End of the Main Sequence (2004)
Adams , Fred C., Graves , Genevieve J. M., Laughlin , Gregory
Terrestrial Planet Formation in Binary Star Systems (2004)
Adams , Fred C., Chambers , John E., Duncan , Martin J., Lissauer , Jack J., Quintana , Elisa V.
The Asymptotic Structure of Space-Time (2003)
Adams, Fred C., Busha, Michael T., Evrard, August E., Wechsler, Risa H.
Astronomical observations strongly suggest that our universe is now accelerating and contains a substantial admixture of dark vacuum energy. Using numerical simulations to study this newly...
Future Evolution of Structure in an Accelerating Universe (2003)
Busha, Michael T., Adams, Fred C., Wechsler, Risa H., Evrard, August E.
Current cosmological data indicate that our universe contains a substantial component of dark vacuum energy that is driving the cosmos to accelerate. We examine the immediate and longer term...
Dynamical Stability of Earth-Like Planetary Orbits in Binary Systems (2003)
David, Eva-Marie, Quintana, Elisa V., Fatuzzo, Marco, Adams, Fred C.
This paper explores the stability of an Earth-like planet orbiting a solar mass star in the presence of an outer-lying intermediate mass companion. The overall goal is to estimate the fraction of...
Adams, Fred C., Graff, David S., Mbonye, Manasse, Richstone, Douglas O.
Motivated by the observed correlation between black hole masses $\mbh$ and the velocity dispersion $\sigma$ of host galaxies, we develop a theoretical model of black hole formation in galactic bulges...
Migration and Dynamical Relaxation in Crowded Systems of Giant Planets (2003)
Adams, Fred C., Laughlin, Greg
This paper explores the intermediate-time dynamics of newly formed solar systems with a focus on possible mechanisms for planetary migration. We consider two limiting corners of the available...
Enhancement of Ambipolar Diffusion Rates through Field Fluctuations (2002)
Fatuzzo, Marco, Adams, Fred C.
Previous treatments of ambipolar diffusion in star-forming molecular clouds do not consider the effects of fluctuations in the fluid fields about their mean values. This paper generalizes the...
Adams, Fred C., Laughlin, Greg
EDITOR'S INTRODUCTION | The universe we know now is but one stage in an almost unimaginably long evolution, starting with the Big Bang when space and time were not yet separated and ending when there...
Astronomical Engineering: A Strategy For Modifying Planetary Orbits (2001)
Korycansky, D.G., Laughlin, Gregory, Adams, Fred C.
The Sun's gradual brightening will seriously compromise the Earth'sbiosphere within ∼ 10 9 years. If Earth's orbit migrates outward,however, the biosphere could remain intact over the...
Astronomical engineering: a strategy for modifying planetary orbits (2001)
Korycansky, D. G., Laughlin, Gregory, Adams, Fred C.
The Sun's gradual brightening will seriously compromise the Earth's biosphere within ~ 1E9 years. If Earth's orbit migrates outward, however, the biosphere could remain intact over the entire...
Modes of Multiple Star Formation (2001)
Adams, Fred C., Myers, Philip C.
This paper argues that star forming environments should be classified into finer divisions than the traditional isolated and clustered modes. Using the observed set of galactic open clusters and...
Constraints on the Birth Aggregate of the Solar System (2000)
Adams, Fred C., Laughlin, Gregory
Using the observed properties of our solar system, in particular the isotopic compositions of meteorites and the regularity of the planetary orbits, we constrain the star formation environment of the...
LETTER: The Life and Times of Extremal Black Holes (2000)
Charged extremal black holes cannot fully evaporate through the Hawking effect and are thus long lived. Over their lifetimes, these black holes take part in a variety of astrophysical processes,...
Adams, Fred C., Graff, David S., Richstone, Douglas O.
We construct a model for the formation of black holes within galactic bulges. The initial state is a slowly rotating isothermal sphere, characterized by effective transport speed $\aeff$ and rotation...
Proton Decay, Black Holes, and Large Extra Dimensions (2000)
Adams, Fred C., Kane, Gordon L., Mbonye, Manasse, Perry, Malcolm J.
We consider proton decay in theories that contain large extra dimensions. If virtual black hole states are allowed by the theory, as is generally the case, then proton decay can proceed via virtual...
We construct a family of semi-analytic models for young open clusters, including a gaseous component and varying assumptions about the distribution function for the stellar component. The parameters...
The Life and Times of Extremal Black Holes (2000)
Charged extremal black holes cannot fully evaporate through the Hawking effect and are thus long lived. Over their lifetimes, these black holes take part in a variety of astrophysical processes,...
Protostellar Disk Formation and Early Evolution (2000)
Adams, Fred C., Laughlin, Gregory
This contribution describes the formation of circumstellar disks and their earliest evolutionary phases when self-gravity in the disk plays a crucial role in eliciting the transport of mass and...
Meyer, Michael R., Adams, Fred C., Hillenbrand, Lynne A., Carpenter, John M., Larson, Richard B.
We summarize recent observational and theoretical progress aimed at understanding the origin of the stellar initial mass function (IMF) with specific focus on galactic star-forming regions. We...
Possible Effects of a Cosmological Constant on Black Hole Evolution (1999)
Adams, Fred C., Mbonye, Manasse, Laughlin, Gregory
We explore possible effects of vacuum energy on the evolution of black holes. If the universe contains a cosmological constant, and if black holes can absorb energy from the vacuum, then black hole...
The Gravitational Demise of Cold Degenerate Stars (1998)
Adams, Fred C., Laughlin, Greg, Mbonye, Manasse, Perry, Malcolm J.
We consider the long term fate and evolution of cold degenerate stars under the action of gravity alone. Although such stars cannot emit radiation through the Hawking mechanism, the wave function of...
Dynamics of Circumstellar Disks (1998)
Nelson, Andrew F., Benz, Willy, Adams, Fred C., Arnett, David
We present a series of 2-dimensional hydrodynamic simulations of massive disks around protostars. We simulate the same physical problem using both a `Piecewise Parabolic Method' (PPM) code and a...
Possible Stellar Metallicity Enhancements from the Accretion of Planets (1997)
Laughlin, Gregory, Adams, Fred C.
A number of recently discovered extrasolar planet candidates have surprisingly small orbits, which may indicate that considerable orbital migration takes place in protoplanetary systems. A natural...
Constraints on the Intergalactic Transport of Cosmic Rays (1997)
Adams, Fred C., Freese, Katherine, Laughlin, Gregory, Tarl{é}, Gregory, Schwadron, Nathan
Motivated by recent experimental proposals to search for extragalactic cosmic rays (including anti-matter from distant galaxies), we study particle propagation through the intergalactic medium (IGM)....
A Dying Universe: The Long Term Fate and Evolution of Astrophysical Objects (1997)
Adams, Fred C., Laughlin, Gregory
This paper outlines astrophysical issues related to the long term fate of the universe. We consider the evolution of planets, stars, stellar populations, galaxies, and the universe itself over time...
Gehman, Curtis S., Adams, Fred C., Watkins, Richard
We study the linear evolution of small perturbations in self-gravitating fluid systems with magnetic fields. We consider wave-like perturbations to nonuniform filamentary and sheet-like hydrostatic...
Implications of White Dwarf Galactic Halos (1996)
Adams, Fred C., Laughlin, Greg
Motivated by recent measurements which suggest that roughly half the mass of the galactic halo may be in the form of white dwarfs, we study the implications of such a halo. We first use current...
A Theory of the IMF for Star Formation in Molecular Clouds (1996)
Adams, Fred C., Fatuzzo, Marco
We present models for the initial mass function (IMF) for stars forming within molecular clouds. These models use the idea that stars determine their own masses through the action of powerful stellar...
Jijina, Jasmin, Adams, Fred C.
In this paper, we study infall collapse solutions for star formation in the small radius limit where the particle orbits become nearly pressure-free. We generalize previous solutions to...
Wave Motions In Molecular Clouds: Results in Two Dimensions (1995)
Gehman, Curtis S., Adams, Fred C., Fatuzzo, Marco, Watkins, Richard
We study the linear evolution of small perturbations in self-gravitating fluid systems in two spatial dimensions; we consider both cylindrical and cartesian (i.e., slab) geometries. The treatment is...
Formal Results Regarding Metric-Space Techniques for the Study of Astrophysical Maps (1994)
Adams, Fred C., Wiseman, Jennifer J.
We extend a newly developed formal system for the description of astrophysical maps. In this formalism, we consider the difference between maps to be the distance between elements of a pseudometric...
A Quantitative Analysis of IRAS Maps of Molecular Clouds (1994)
Wiseman, Jennifer J., Adams, Fred C.
We present an analysis of IRAS maps of five molecular clouds: Orion, Ophiuchus, Perseus, Taurus, and Lupus. For the classification and description of these astrophysical maps, we use a newly...
The Scalar Field Potential in Inflationary Models: Reconstruction and Further Constraints (1994)
Adams, Fred C., Freese, Katherine
In this paper, we present quantitative constraints on the scalar field potential for a general class of inflationary models. (1) We first consider the reconstruction of the inflationary potential for...
Nonlinear stationary waves and solitary waves in fluid systems with long-range forces (1993)
Adams, Fred C., Fatuzzo, Marco, Watkins, Richard
We study a class of nonlinear model equations which represent one-dimensional fluid systems with long range forces (such as gravity). We present elementary theorems which constrain the allowed types...
General Analytic Results for Nonlinear Waves and Solitons in Molecular Clouds (1993)
Adams, Fred C., Fatuzzo, Marco, Watkins, Richard
We study nonlinear wave phenomena in self-gravitating fluid systems, with a particular emphasis on applications to molecular clouds. This paper presents analytical results for one spatial dimension....
General Solutions for Tunneling of Scalar Fields with Quartic Potentials (1993)
For the theory of a single scalar field $\varphi$ with a quartic potential $V(\varphi)$, we find semi-analytic expressions for the Euclidean action in both four and three dimensions. The action in...
Baryon Number Diffusion and Instabilities in the Quark/Hadron Phase Transition (1992)
Adams, Fred C., Freese, Katherine, Langer, J. S.
Hadron bubbles that nucleate with radius $R_{nuc}$ in a quark sea (if the phase transition is first order) are shown to be unstable to the growth of nonspherical structure when the bubble radii...