Alan P. Boss

Carnegie Institution for Science

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Alycia J. Weinberger

Carnegie Institution for Science

Laird M. Close

University of Arizona

Michael C. Liu

University of Hawaii System

G. Anglada‐Escudé

Institute of Space Sciences

H. A. T. Vanhala

Carnegie Observatories

Andrew Skemer

University of California, Santa Cruz

Dimitri Mawet

California Institute of Technology

E. Nielsen

New Mexico State University

Sandra A. Keiser

Carnegie Institution for Science

P. N. Foster

University of Bristol

Cooperative Institutions

Purple Mountain Observatory

714

Centre National de la Recherche Scientifique

155

California Institute of Technology

129

Ames Research Center

119

Max Planck Society

109

University of Arizona

102

Center for Astrophysics Harvard & Smithsonian

Goddard Space Flight Center

University of California, Berkeley

Jet Propulsion Laboratory

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Formation of the Protosolar Nebula

W. M. Tscharnuter Alan P. Boss

Theoretical models are discussed of the collapse of a dense molecular cloud core to form the protosolar nebula that produce the sun and the planet. The theoretical models use the equations of hydrodynamics, gravitation, and radiative transfer to follow the time evolution of a cloud collapsing under its own self-gravity. Both semi-analytical and fully numerical solutions (in two and three spatial dimensions) were calculated by several workers, One challenge is to find a set of initial conditions that will lead to the formation of a suitable protosolar nebula. Detailed results are shown for 2-D models, both with and without turbulent viscosity for redistributing angular momentum, and for 3-D models investigating the strength of gravitational torques associated with nonaxisymmetry produced during the collapse phase.

Source

Cite

Citations (15)

SUPERNOVA-TRIGGERED MOLECULAR CLOUD CORE COLLAPSE AND THE RAYLEIGH-TAYLOR FINGERS THAT POLLUTED THE SOLAR NEBULA

The Astrophysical Journal Letters (2012)

Alan P. Boss Sandra A. Keiser

A supernova is a likely source of short-lived radioisotopes (SLRIs) that were present during the formation of the earliest solar system solids. A suitably thin and dense supernova shock wave may be capable of triggering the self-gravitational collapse of a molecular cloud core while simultaneously injecting SLRIs. Axisymmetric hydrodynamics models have shown that this injection occurs through a number of Rayleigh-Taylor (RT) rings. Here we use the FLASH adaptive mesh refinement (AMR) hydrodynamics code to calculate the first fully three dimensional (3D) models of the triggering and injection process. The axisymmetric RT rings become RT fingers in 3D. While ~ 100 RT fingers appear early in the 3D models, only a few RT fingers are likely to impact the densest portion of the collapsing cloud core. These few RT fingers must then be the source of any SLRI spatial heterogeneity in the solar nebula inferred from isotopic analyses of chondritic meteorites. The models show that SLRI injection efficiencies from a supernova several pc away fall at the lower end of the range estimated for matching SLRI abundances, perhaps putting them more into agreement with recent reassessments of the level of 60Fe present in the solar nebula.

Solar mass

10.1088/2041-8205/756/1/l9

Cite

Citations (27)

Binary Star Formation in Magnetic Molecular Clouds

DDA (1999)

Alan P. Boss

Source

Cite

Citations (0)

Spatial Heterogeneity of Short-lived Radioisotopes and of Stable Oxygen Isotopes in the Solar Nebula

Lunar and Planetary Science Conference (2007)

Alan P. Boss

Source

Cite

Citations (0)

Extrasolar planets: Past, present, and future

Cambridge University Press eBooks (2008)

Alan P. Boss

Human beings have long thought that planetary systems similar to our own should exist around stars other than the Sun. However, the astronomical search for planets outside our Solar System has had a dismal history of decades of discoveries that were announced, but could not be confirmed. All that changed in 1995, when we entered the era of the discovery of extrasolar planetary systems orbiting main-sequence stars. To date, well over 130 planets have been found outside our Solar System, ranging from the fairly familiar to the weirdly unexpected. Nearly all of the new planets discovered to date appear to be gas giant planets similar to our Jupiter and Saturn, though with very different orbits about their host stars. In the last year, three planets with much lower masses have been found, similar to those of Uranus and Neptune, but it is not yet clear if they are also ice giant planets, or perhaps rock giant planets, i.e., super-Earths. The long-term goal is to discover and characterize nearby Earth-like, habitable planets. A visionary array of space-based telescopes has been planned that will carry out this incredible search over the next several decades.

10.1017/cbo9780511536304.003

Cite

Citations (0)

Rapid Formation of Super-Earths around M Dwarf Stars

The Astrophysical Journal (2006)

Alan P. Boss

While the recent microlensing discoveries of super-Earths orbiting two M dwarf stars have been taken as support for the core accretion mechanism of giant planet formation, we show here that these planets could also have been formed by the competing mechanism of disk instability, coupled with photoevaporative loss of their gaseous envelopes by a strong external source of UV radiation, i.e., an O star. M dwarfs that form in regions of future high-mass star formation would then be expected to have super-Earths orbiting at distances of several AU and beyond, while those that form in regions of low-mass star formation would be expected to have gas giants at those distances. Given that most stars are born in the former rather than in the latter regions, M dwarfs should have significantly more super-Earths than gas giants, as seems to be indicated by the microlensing surveys.

Gravitational microlensing

Gas giant

Giant planet

10.1086/505533

Cite

Citations (100)

COLLAPSE AND FRAGMENTATION OF MAGNETIC MOLECULAR CLOUD CORES WITH THE Enzo AMR MHD CODE. II. PROLATE AND OBLATE CORES

The Astrophysical Journal (2014)

Alan P. Boss Sandra A. Keiser

We present the results of a large suite of three-dimensional models of the collapse of magnetic molecular cloud cores using the adaptive mesh refinement code Enzo2.2 in the ideal magnetohydrodynamics approximation. The cloud cores are initially either prolate or oblate, centrally condensed clouds with masses of 1.73 or 2.73 M☉, respectively. The radial density profiles are Gaussian, with central densities 20 times higher than boundary densities. A barotropic equation of state is used to represent the transition from low density isothermal phases, to high density optically thick phases. The initial magnetic field strength ranges from 6.3 to 100 μG, corresponding to clouds that are strongly to marginally supercritical, respectively, in terms of the mass to magnetic flux ratio. The magnetic field is initially uniform and aligned with the clouds' rotation axes, with initial ratios of rotational to gravitational energy ranging from 10−4 to 0.1. Two significantly different outcomes for collapse result: (1) formation of single protostars with spiral arms, and (2) fragmentation into multiple protostar systems. The transition between these two outcomes depends primarily on the initial magnetic field strength, with fragmentation occurring for mass to flux ratios greater than about 14 times the critical ratio for prolate clouds. Oblate clouds typically fragment into several times more clumps than prolate clouds. Multiple, rather than binary, system formation is the general rule in either case, suggesting that binary stars are primarily the result of the orbital dissolution of multiple protostar systems.

Protostar

Magnetic cloud

10.1088/0004-637x/794/1/44

Cite

Citations (10)

Modeling Scattered Light Images from a Planet-Forming Disk

American Astronomical Society Meeting Abstracts (2006)

Hannah Jang‐Condell Alan P. Boss

Source

Cite

Citations (0)

THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. V. CANDIDATE SUBSTELLAR COMPANIONS TO BINARY SYSTEMS

American Astronomical Society (2010)

Matthew W. Muterspaugh Benjamin F. Lane S. R. Kulkarni M. Konacki B. F. Burke

The Palomar High-precision Astrometric Search for Exoplanet Systems monitored 51 subarcsecond binary systems to evaluate whether tertiary companions as small as Jovian planets orbited either the primary or secondary stars, perturbing their otherwise smooth Keplerian motions. Six binaries are presented that show evidence of substellar companions orbiting either the primary or secondary star. Of these six systems, the likelihoods of two of the detected perturbations to represent real objects are considered to be high confidence, while the remaining four systems are less certain and will require continued observations for confirmation.

Astrometry

Primary (astronomy)

Source

Cite

Citations (1)

Spectroscopic signatures of infall in young protostellar systems

The Astrophysical Journal (1994)

Christopher K. Walker Gopal Narayanan Alan P. Boss

view Abstract Citations (73) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectroscopic Signatures of Infall in Young Protostellar Systems Walker, Christopher K. ; Narayanan, Gopal ; Boss, Alan P. Abstract We present the first radiative transfer calculations of millimeter and submillimeter molecular line emission from 'self-consistent' models of nonspherical, collapsing, rotating protostellar systems. We find that: (1) the morphology of the gas and dust emission is a strong function of collapse time and angular resolution, (2) centroid velocity maps can provide a distinct infall signature, and (3) the unambiguous detection of infall toward binary systems becomes more difficult with increasing binary separation. Publication: The Astrophysical Journal Pub Date: August 1994 DOI: 10.1086/174528 Bibcode: 1994ApJ...431..767W Keywords: Emission Spectra; Gravitational Collapse; Line Spectra; Molecular Spectra; Pre-Main Sequence Stars; Radiative Transfer; Spectral Signatures; Star Formation; Abundance; Angular Resolution; Cosmic Dust; Cosmology; Spectrum Analysis; Stellar Evolution; Velocity Distribution; Astrophysics; STARS: BINARIES: GENERAL; ISM: DUST; EXTINCTION; RADIATIVE TRANSFER; STARS: FORMATION; STARS: PRE--MAIN-SEQUENCE full text sources ADS | data products SIMBAD (1)

Extinction (optical mineralogy)

Submillimeter Array

10.1086/174528

Cite

Citations (70)