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Related papers: Planetesimal Initial Mass Functions following Diff…

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Numerical hydrodynamics simulations have established that disks which are evolved under the condition of local isothermality will fragment into small dense clumps due to gravitational instabilities when the Toomre stability parameter $Q$ is…

Astrophysics · Physics 2009-06-23 Richard H. Durisen , Thomas W. Hartquist , Megan K. Pickett

Theoretical arguments and indirect observational evidence suggest that the stellar initial mass function (IMF) may evolve with time, such that it is more weighted toward high mass stars at higher redshift. Here we test this idea by…

Astrophysics · Physics 2010-01-07 Pieter van Dokkum

The stellar initial mass functions (IMFs) for the Galactic bulge, the Milky Way, other galaxies, clusters of galaxies, and the integrated stars in the Universe are composites from countless individual IMFs in star clusters and associations…

Astrophysics · Physics 2008-11-26 Bruce G. Elmegreen

Spectroscopic analyses of gravity-sensitive line strengths give growing evidence towards an excess of low-mass stars in massive early-type galaxies (ETGs). Such a scenario requires a bottom-heavy initial mass function (IMF). However, strong…

Astrophysics of Galaxies · Physics 2015-06-23 I. Ferreras , C. Weidner , A. Vazdekis , F. La Barbera

Planet formation in the solar system was started when the first planetesimals were formed from the gravitational collapse of pebble clouds. Numerical simulations of this process, especially in the framework of streaming instability, produce…

Earth and Planetary Astrophysics · Physics 2024-11-27 Jiahan Shi , Matthias Bartelmann , Hubert Klahr , Cornelis P. Dullemond

We use a series of magnetohydrodynamic simulations including both radiative and protostellar outflow feedback to study the environmental variation of the initial mass function. The simulations represent a carefully-controlled experiment…

Astrophysics of Galaxies · Physics 2022-09-28 Tabassum S Tanvir , Mark R Krumholz , Christoph Federrath

Most of planet formation models that incorporate planetesimal fragmentation consider a catastrophic impact energy threshold for basalts at a constant velocity of 3 km/s during all the process of the formation of the planets. However, as…

Earth and Planetary Astrophysics · Physics 2019-05-29 I. L. San Sebastián , O. M. Guilera , M. G. Parisi

Three component models of the IMF are made to consider possible origins for the observed relative variations in the numbers of brown dwarfs, solar-to-intermediate mass stars, and high mass stars. Three distinct physical processes are noted.…

Astrophysics · Physics 2009-11-10 Bruce G. Elmegreen

The turnover in the stellar initial mass function (IMF) at low mass suggests the presence of two independent mass functions that combine in different ways above and below a characteristic mass given by the thermal Jeans mass in the cloud.…

Astrophysics · Physics 2009-10-31 Bruce Elmegreen

The stellar initial mass function (IMF) is a key property of stellar populations. There is growing evidence that the classical star-formation mechanism by the direct cloud fragmentation process has difficulties reproducing the observed…

Astrophysics of Galaxies · Physics 2015-02-19 Ingo Thies , Jan Pflamm-Altenburg , Pavel Kroupa , Michael Marks

Deviations from a universal, MW-like, Stellar Initial Mass Function (IMF) have been reported for distant galaxies, although the physical reason behind the observed variations is still matter of ongoing debate. In this paper, we present an…

Astrophysics of Galaxies · Physics 2015-06-19 Fabio Fontanot

We show that the same initial mass function (IMF) can result from very different modes of star formation from very similar underlying core and/or system mass functions. In particular, we show that the canonical IMF can be recovered from…

Astrophysics of Galaxies · Physics 2015-05-13 Simon P Goodwin , M B N Kouwenhoven

The hypothesis of a universal initial mass function (IMF) -- motivated by observations in nearby stellar systems -- has been recently challenged by the discovery of a systematic variation of the IMF with the central velocity dispersion,…

Recent results form the James Webb Space Telescope (JWST) report space densities for bright and massive galaxies at z>7 that far exceed expectations of theoretical models of galaxy formation, prompting a revision of our understanding of the…

This chapter highlights the properties of turbulence and meso-scale flow structures in protoplanetary disks and their role in the planet formation process. Here we focus on the formation of planetesimals from a gravitational collapse of a…

Earth and Planetary Astrophysics · Physics 2018-12-05 Hubert Klahr , Thomas Pfeil , Andreas Schreiber

Observations of the stellar initial mass function are reviewed. The flattening at low mass is evidence for a characteristic mass in star formation, which could be the minimum stellar mass for the onset of deuterium burning or the thermal…

Astrophysics · Physics 2007-05-23 Bruce G. Elmegreen

There is growing evidence that planet formation begins early, within the $\lesssim 1$Myr Class 0/I phase, when infall dominates disk dynamics. Our goal is to determine if Class 0/I disks reach the conditions needed to form planetesimals…

Earth and Planetary Astrophysics · Physics 2025-04-21 Daniel Carrera , Abigail Davenport , Jacob B. Simon , Hans Baehr , Til Birnstiel , Cassandra Hall , David Rea , Sebastian Stammler

We investigate the most plausible stellar Initial Mass Function (IMF) and the main origin of the tilt of the Fundamental Plane (FP) for old, massive early-type galaxies. We consider a sample of 13 bright galaxies of the Coma cluster and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 C. Grillo , R. Gobat

An unsolved issue in the standard core accretion model for gaseous planet formation is how kilometre-sized planetesimals form from, initially, micron-sized dust grains. Solid growth beyond metre sizes can be difficult both because the…

Astrophysics · Physics 2009-11-11 W. K. M. Rice , G. Lodato , J. E. Pringle , P. J. Armitage , I. A. Bonnell

Observational studies are showing that the galaxy-wide stellar initial mass function are top-heavy in galaxies with high star-formation rates (SFRs). Calculating the integrated galactic stellar initial mass function (IGIMF) as a function of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Carsten Weidner , Pavel Kroupa , Jan Pflamm-Altenburg , Alexandre Vazdekis