Mapping the Present-Day Prestellar Core Mass Function into the Stellar IMF

2014 ◽  
pp. 309-315
Author(s):  
Katy Holman ◽  
Stefanie K. Walch ◽  
Simon Goodwin ◽  
Anthony Peter Whitworth
Keyword(s):  
Mass Function ◽  
Core Mass

scholarly journals Origin of the prestellar core mass function and link to the IMF – Herschel first results

2010 ◽  
Vol 6 (S270) ◽  
pp. 255-262 ◽  
Author(s):  
Ph. André ◽  
A. Men'shchikov ◽  
V. Könyves ◽  
D. Arzoumanian
Keyword(s):  
Gravitational Instability ◽  
Mass Function ◽  
Initial Mass Function ◽  
Mhd Turbulence ◽  
Core Mass ◽  
Thin Filaments ◽  
Close Relationship ◽  
Prestellar Cores ◽  
First Results ◽  
The Imf

AbstractWe briefly review ground-based (sub)millimeter dust continuum observations of the prestellar core mass function (CMF) and its connection to the stellar initial mass function (IMF). We also summarize the first results obtained on this topic from the Herschel Gould Belt survey, one of the largest key projects with the Herschel Space Observatory. Our early findings with Herschel confirm the existence of a close relationship between the CMF and the IMF. Furthermore, they suggest a scenario according to which the formation of prestellar cores occurs in two main steps: 1) complex networks of long, thin filaments form first, probably as a result of interstellar MHD turbulence; 2) the densest filaments then fragment and develop prestellar cores via gravitational instability.

scholarly journals Simulations of the IMF in Clusters

2010 ◽  
Vol 6 (S270) ◽  
pp. 151-158
Author(s):  
Ralph E. Pudritz
Keyword(s):  
Equations Of State ◽  
Stellar Dynamics ◽  
Mass Function ◽  
Initial Mass Function ◽  
Core Mass ◽  
Numerical Work ◽  
Computational Approaches ◽  
The Core ◽  
The Imf

AbstractWe review computational approaches to understanding the origin of the Initial Mass Function (IMF) during the formation of star clusters. We examine the role of turbulence, gravity and accretion, equations of state, and magnetic fields in producing the distribution of core masses - the Core Mass Function (CMF). Observations show that the CMF is similar in form to the IMF. We focus on feedback processes such as stellar dynamics, radiation, and outflows can reduce the accreted mass to give rise to the IMF. Numerical work suggests that filamentary accretion may play a key role in the origin of the IMF.

scholarly journals Properties of the dense core population in Orion B as seen by the Herschel Gould Belt survey

2020 ◽  
Vol 635 ◽  
pp. A34 ◽  
Author(s):  
V. Könyves ◽  
Ph. André ◽  
D. Arzoumanian ◽  
N. Schneider ◽  
A. Men’shchikov ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Column Density ◽  
Mass Function ◽  
Smooth Transition ◽  
High Mass ◽  
Core Mass ◽  
Gould Belt ◽  
Dense Cores ◽  
Prestellar Cores ◽  
Consistent Manner

We present a detailed study of the Orion B molecular cloud complex (d ~ 400 pc), which was imaged with the PACS and SPIRE photometric cameras at wavelengths from 70 to 500 μm as part of the Herschel Gould Belt survey (HGBS). We release new high-resolution maps of column density and dust temperature for the whole complex, derived in the same consistent manner as for other HGBS regions. In the filamentary subregions NGC 2023 and 2024, NGC 2068 and 2071, and L1622, a total of 1768 starless dense cores were identified based on Herschel data, 490–804 (~28−45%) of which are self-gravitating prestellar cores that will likely form stars in the future. A total of 76 protostellar dense cores were also found. The typical lifetime of the prestellar cores was estimated to be tpreOrionB = 1.7−0.6+0.8Myr. The prestellar core mass function (CMF) derived for the whole sample of prestellar cores peaks at ~0.5 M⊙ (in dN/dlogM format) and is consistent with a power-law with logarithmic slope −1.27 ± 0.24 at the high-mass end, compared to the Salpeter slope of − 1.35. In the Orion B region, we confirm the existence of a transition in prestellar core formation efficiency (CFE) around a fiducial value AVbg ~ 7 mag in background visual extinction, which is similar to the trend observed with Herschel in other regions, such as the Aquila cloud. This is not a sharp threshold, however, but a smooth transition between a regime with very low prestellar CFE at AVbg < 5 and a regime with higher, roughly constant CFE at AVbg ≳ 10. The total mass in the form of prestellar cores represents only a modest fraction (~20%) of the dense molecular cloud gas above AVbg ≳ 7 mag. About 60–80% of the prestellar cores are closely associated with filaments, and this fraction increases up to >90% when a more complete sample of filamentary structures is considered. Interestingly, the median separation observed between nearest core neighbors corresponds to the typical inner filament width of ~0.1 pc, which is commonly observed in nearby molecular clouds, including Orion B. Analysis of the CMF observed as a function of background cloud column density shows that the most massive prestellar cores are spatially segregated in the highest column density areas, and suggests that both higher- and lower-mass prestellar cores may form in denser filaments.

scholarly journals The highly variable time evolution of star-forming cores identified with dendrograms

2020 ◽  
Vol 497 (4) ◽  
pp. 4517-4534
Author(s):  
Rachel A Smullen ◽  
Kaitlin M Kratter ◽  
Stella S R Offner ◽  
Aaron T Lee ◽  
Hope How-Huan Chen
Keyword(s):  
Time Evolution ◽  
Mass Function ◽  
Density Field ◽  
Initial Mass Function ◽  
Stellar Content ◽  
Core Mass ◽  
Structure Variation ◽  
Star Forming ◽  
The Core ◽  
Dense Cores

ABSTRACT We investigate the time evolution of dense cores identified in molecular cloud simulations using dendrograms, which are a common tool to identify hierarchical structure in simulations and observations of star formation. We develop an algorithm to link dendrogram structures through time using the three-dimensional density field from magnetohydrodynamical simulations, thus creating histories for all dense cores in the domain. We find that the population-wide distributions of core properties are relatively invariant in time, and quantities like the core mass function match with observations. Despite this consistency, an individual core may undergo large (&gt;40 per cent), stochastic variations due to the redefinition of the dendrogram structure between time-steps. This variation occurs independent of environment and stellar content. We identify a population of short-lived (&lt;200 kyr) overdensities masquerading as dense cores that may comprise $\sim\!20$ per cent of any time snapshot. Finally, we note the importance of considering the full history of cores when interpreting the origin of the initial mass function; we find that, especially for systems containing multiple stars, the core mass defined by a dendrogram leaf in a snapshot is typically less than the final system stellar mass. This work reinforces that there is no time-stable density contour that defines a star-forming core. The dendrogram itself can induce significant structure variation between time-steps due to small changes in the density field. Thus, one must use caution when comparing dendrograms of regions with different ages or environment properties because differences in dendrogram structure may not come solely from the physical evolution of dense cores.

scholarly journals DENSE CORES IN THE PIPE NEBULA: AN IMPROVED CORE MASS FUNCTION

2009 ◽  
Vol 699 (1) ◽  
pp. 742-753 ◽  
Author(s):  
J. M. Rathborne ◽  
C. J. Lada ◽  
A. A. Muench ◽  
J. F. Alves ◽  
J. Kainulainen ◽  
...  
Keyword(s):  
Mass Function ◽  
Core Mass ◽  
Dense Cores

scholarly journals Mapping the core mass function on to the stellar initial mass function: multiplicity matters

2013 ◽  
Vol 432 (4) ◽  
pp. 3534-3543 ◽  
Author(s):  
K. Holman ◽  
S. K. Walch ◽  
S. P. Goodwin ◽  
A. P. Whitworth
Keyword(s):  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Core Mass ◽  
The Core ◽  
Stellar Initial Mass Function

scholarly journals A SCUBA survey of Orion – the low-mass end of the core mass function

2007 ◽  
Vol 374 (4) ◽  
pp. 1413-1420 ◽  
Author(s):  
D. Nutter ◽  
D. Ward-Thompson
Keyword(s):  
Mass Function ◽  
Core Mass ◽  
The Core ◽  
Low Mass

scholarly journals Sculpting the Sub-Saturn Occurrence Rate via Atmospheric Mass Loss

2022 ◽  
Vol 924 (1) ◽  
pp. 9
Author(s):  
Tim Hallatt ◽  
Eve J. Lee
Keyword(s):  
Mass Loss ◽  
Mass Function ◽  
Occurrence Rate ◽  
Rotating Stars ◽  
Core Mass ◽  
Orbital Periods ◽  
M Stars ◽  
Gas Accretion ◽  
Rapidly Rotating Stars ◽  
Atmospheric Mass

Abstract The sub-Saturn (∼4–8 R ⊕) occurrence rate rises with orbital period out to at least ∼300 days. In this work we adopt and test the hypothesis that the decrease in their occurrence toward the star is a result of atmospheric mass loss, which can transform sub-Saturns into sub-Neptunes (≲4 R ⊕) more efficiently at shorter periods. We show that under the mass-loss hypothesis, the sub-Saturn occurrence rate can be leveraged to infer their underlying core mass function, and, by extension, that of gas giants. We determine that lognormal core mass functions peaked near ∼10–20 M ⊕ are compatible with the sub-Saturn period distribution, the distribution of observationally inferred sub-Saturn cores, and gas-accretion theories. Our theory predicts that close-in sub-Saturns should be ∼50% less common and ∼30% more massive around rapidly rotating stars; this should be directly testable for stars younger than ≲500 Myr. We also predict that the sub-Jovian desert becomes less pronounced and opens up at smaller orbital periods around M stars compared to solar-type stars (∼0.7 days versus ∼3 days). We demonstrate that exceptionally low-density sub-Saturns, “super-puffs,” can survive intense hydrodynamic escape to the present day if they are born with even larger atmospheres than they currently harbor; in this picture, Kepler 223 d began with an envelope ∼1.5× the mass of its core and is currently losing its envelope at a rate of ∼2 × 10−3 M ⊕ Myr−1. If the predictions from our theory are confirmed by observations, the core mass function we predict can also serve to constrain core formation theories of gas-rich planets.

scholarly journals A possible far-ultraviolet flux-dependent core mass function in NGC 6357

2021 ◽  
Author(s):  
J. Brand ◽  
A. Giannetti ◽  
F. Massi ◽  
J.G.A. Wouterloot ◽  
C. Verdirame
Keyword(s):  
Mass Function ◽  
Core Mass ◽  
Far Ultraviolet

Prestellar Core Collisions - Impact on the formation of the CMF? A case study on FeSt 1-457

2018 ◽  
Vol 14 (S345) ◽  
pp. 328-329
Author(s):  
Gabor I. Herbst-Kiss ◽  
Joao Alves
Keyword(s):  
Molecular Cloud ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Core Mass ◽  
Preliminary Results ◽  
The Core ◽  
Prestellar Cores

AbstractThe initial mass function (IMF) is a profoundly studied subject, however its origin is still unclear and heavily disputed. The Core Mass Function (CMF) has a remarkable resemblance to a shifted IMF along the mass axis of a factor of 3. This CMF has been observed amongst others in the Pipe Nebula, a calm molecular cloud at approximately 130 pc. We study the origin of the CMF under the assumption that collisions and merging of prestellar cores shape the CMF. We present our preliminary results of core collisions for the well known FeSt 1-457.

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