Outflow Feedback Regulated Massive Star Formation in Parsec-Scale Cluster Forming Clumps (2009)
Wang, Peng, Li, Zhi-Yun, Abel, Tom, Nakamura, Fumitaka
(Abridged) We investigate massive star formation in turbulent, magnetized, parsec-scale clumps of molecular clouds including protostellar outflow feedback using Enzo-based MHD simulations with...
Magnetic Braking and Protostellar Disk Formation: Ambipolar Diffusion (2008)
Mellon, Richard R., Li, Zhi-Yun
It is established that the formation of rotationally supported disks during the main accretion phase of star formation is suppressed by a moderately strong magnetic field in the ideal MHD limit....
The Molecular Ridge Close to 30 Doradus in the Large Magellanic Cloud (2008)
Ott, Juergen, Wong, Tony, Pineda, Jorge L., Hughes, Annie, Muller, Erik, Li, Zhi-Yun, ...
With the ATNF Mopra telescope we are performing a survey in the 12CO(1-0) line to map the molecular gas in the Large Magellanic Cloud (LMC). For some regions we also obtained interferometric maps of...
Magnetically Regulated Star Formation in 3D: The Case of Taurus Molecular Cloud Complex (2008)
Nakamura, Fumitaka, Li, Zhi-Yun
We carry out three-dimensional MHD simulations of star formation in turbulent, magnetized clouds, including ambipolar diffusion and feedback from protostellar outflows. The calculations focus on...
The Formation of Distributed and Clustered Stars in Molecular Clouds (2008)
Megeath, S. T., Li, Zhi-Yun, Nordlund, Aake
During the last two decades, the focus of star formation research has shifted from understanding the collapse of a single dense core into a star to studying the formation hundreds to thousands of...
The molecular ridge close to 30 Doradus in the Large Magellanic Cloud (2008)
Ott, Jurgen, Wong, Tony, Pineda, Jorge L., Hughes, Annie, Muller, Erik, Li, Zhi-Yun, ...
With the ATNF Mopra telescope we are performing a survey in the 12CO(1-0) line to map the molecular gas in the Large Magellanic Cloud. For some regions we also obtained interferometric maps of the...
The molecular ridge close to 30 Doradus in the Large Magellanic Cloud (2008)
Ott, Jürgen, Wong, Tony, Pineda, Jorge L., Hughes, Annie, Muller, Erik, Li, Zhi-Yun, ...
With the ATNF Mopra telescope we are performing a survey in the ^(12)CO(1–0) line to map the molecular gas in the Large Magellanic Cloud. For some regions we also obtained interferometric maps of...
The molecular ridge close to 30 Doradus in the Large Magellanic Cloud (2008)
Ott, Jurgen, Wong, Tony, Pineda, Jorge L., Hughes, Annie, Muller, Erik, Li, Zhi-Yun, ...
With the ATNF Mopra telescope we are performing a survey in the 12CO(1-0) line to map the molecular gas in the Large Magellanic Cloud. For some regions we also obtained interferometric maps of the...
Magnetic Braking and Protostellar Disk Formation: The Ideal MHD Limit (2007)
Mellon, Richard R., Li, Zhi-Yun
Magnetic fields are usually considered dynamically important in star formation when the dimensionless mass-to-flux ratio is close to, or less than, unity (lambda~100, they merge together to form a...
Protostellar Turbulence Driven by Collimated Outflows (2007)
Nakamura, Fumitaka, Li, Zhi-Yun
The majority of stars are thought to form in clusters. Cluster formation in dense clumps of molecular clouds is strongly influenced, perhaps controlled, by supersonic turbulence. We have previously...
Magnetocentrifugal Winds in 3D: Nonaxisymmetric Steady State (2006)
Anderson, Jeffrey M., Li, Zhi-Yun, Krasnopolsky, Ruben, Blandford, Roger D.
Outflows can be loaded and accelerated to high speeds along rapidly rotating, open magnetic field lines by centrifugal forces. Whether such magnetocentrifugally driven winds are stable is a...
Cluster Formation in Protostellar Outflow-Driven Turbulence (2005)
Li, Zhi-Yun, Nakamura, Fumitaka
Most, perhaps all, stars go through a phase of vigorous outflow during formation. We examine, through 3D MHD simulation, the effects of protostellar outflows on cluster formation. We find that the...
Nakamura, Fumitaka, Li, Zhi-Yun
The efficiency of star formation, defined as the ratio of the stellar to total (gas and stellar) mass, is observed to vary from a few percent in regions of dispersed star formation to about a third...
The Structure of Magnetocentrifugal Winds I. Steady Mass Loading (2004)
Anderson, Jeffrey M., Li, Zhi-Yun, Krasnopolsky, Ruben, Blandford, Roger D.
We present the results of a series of time-dependent numerical simulations of cold, magnetocentrifugally launched winds from accretion disks. Our simulations span four and half decades of mass...
Magnetically Regulated Star Formation in Turbulent Clouds (2004)
Li, Zhi-Yun, Nakamura, Fumitaka
We investigate numerically the combined effects of supersonic turbulence, strong magnetic fields and ambipolar diffusion on cloud evolution leading to star formation. We find that, in clouds that are...
Does Magnetic Levitation or Suspension Define the Masses of Forming Stars? (2003)
Shu, Frank H., Li, Zhi-Yun, Allen, Anthony
We investigate whether magnetic tension can define the masses of forming stars by holding up the subcritical envelope of a molecular cloud that suffers gravitational collapse of its supercritical...
The Diversity of Gamma-Ray Bursts and the Surroundings of Massive Stars (2003)
Chevalier, Roger A., Li, Zhi-Yun, Fransson, Claes
The finding of a Type Ic supernova connected with GRB 030329 showed a massive star origin for this burst, supporting evidence for this association in previous bursts with lightcurve bumps at the...
Magneto-Centrifugal Launching of Jets from Accretion Disks. II: Inner Disk-Driven Winds (2003)
Krasnopolsky, Ruben, Li, Zhi-Yun, Blandford, Roger D.
We follow numerically the time evolution of axisymmetric outflows driven magneto-centrifugally from the inner portion of accretion disks, from their launching surface to large, observable distances....
Binary and Multiple Star Formation in Magnetic Clouds: Bar Growth and Fragmentation (2003)
Nakamura, Fumitaka, Li, Zhi-Yun
We study the non-axisymmetric evolution of magnetized clouds, using a 2D MHD code based on the physically motivated thin-disk approximation. We found that such clouds become unstable to...
Locating the Launching Region of T Tauri Winds: The Case of DG Tau (2003)
Anderson, Jeffrey M., Li, Zhi-Yun, Krasnopolsky, Ruben, Blandford, Roger
It is widely believed that T Tauri winds are driven magnetocentrifugally from accretion disks close to the central stars. The exact launching conditions are uncertain. We show that a general relation...
Wind-Interaction Models for the Early Afterglows of Gamma-Ray Bursts: The Case of GRB 021004 (2003)
Li, Zhi-Yun, Chevalier, Roger A.
Wind-interaction models for gamma-ray burst afterglows predict that the optical emission from the reverse shock drops below that from the forward shock within 100s of seconds of the burst. The...
Isolated low-mass stars are formed, in the standard picture, from the collapse of dense cores condensed out of strongly magnetized molecular clouds. The dynamically collapsing inflow traps nearly...
On the Formation of Binary Stars and Small Stellar Groups in Magnetically Subcritical Clouds (2002)
Nakamura, Fumitaka, Li, Zhi-Yun
In the standard scenario of isolated low-mass star formation, strongly magnetized molecular clouds are envisioned to condense gradually into cores, driven by ambipolar diffusion. Once the cores...
Nakamura, Fumitaka, Li, Zhi-Yun
We have begun a systematic numerical study of the nonlinear growth of nonaxisymmetric perturbations during the ambipolar diffusion-driven evolution of initially magnetically subcritical molecular...
Li, Zhi-Yun, Shematovich, V. I., Wiebe, D. S., Shustov, B. M.
We develop a detailed chemical model for the starless cores of strongly magnetized molecular clouds, with the ambipolar diffusion-driven dynamic evolution of the clouds coupled to the chemistry...
Interaction Models for GRB Afterglows (2001)
Li, Zhi-Yun, Chevalier, Roger A.
We review interaction models for GRB afterglows, with an eye on constraining the nature of their progenitors and the geometry of explosion. Evidence is presented for two types of progenitors. The...
Structure of Magnetocentrifugal Disk-Winds: From the Launching Surface to Large Distances (2001)
Krasnopolsky, Ruben, Li, Zhi-Yun, Blandford, Roger D.
Protostellar jets and winds are probably driven magnetocentrifugally from the surface of accretion disks close to the central stellar objects. The exact launching conditions on the disk, such as the...
Ring Formation in Magnetically Subcritical Clouds and Multiple Star Formation (2001)
We study numerically the ambipolar diffusion-driven evolution of non-rotating, magnetically subcritical, disk-like molecular clouds, assuming axisymmetry. Previous similar studies have concentrated...
Wind Interaction Models for the Afterglows of GRB 991208 and GRB 000301C (2000)
Li, Zhi-Yun, Chevalier, Roger A.
The simplest model of the afterglows of the gamma-ray bursts (GRBs) envisions a spherical blast wave with a power-law distribution of electron energy above some cutoff running into a constant density...
Wind Interaction Models for Gamma-Ray Burst Afterglows: The Case for Two Types of Progenitors (1999)
Chevalier, Roger A., Li, Zhi-Yun
Beginning with the $\gamma$-ray bursts GRB 970228 and GRB 970508, a standard model for the interpretation of GRB afterglows emerged involving synchrotron emission from a constant energy blast wave...
In the standard picture of isolated star formation, dense ``starless'' cores are formed out of magnetic molecular clouds due to ambipolar diffusion. Under the simplest spherical geometry, I...
Radio Supernova SN 1998bw and Its Relation to GRB 980425 (1999)
Li, Zhi-Yun, Chevalier, Roger A.
SN 1998bw is an unusual Type Ic supernova that may be associated with the $\gamma$-ray burst GRB 980425. We use a synchrotron self-absorption model for its radio emission to deduce that the...
Aspects of relativistic MHD wind theory /--by Zhi-Yun Li. (1993)
Thesis (Ph. D.)--University of Colorado, 1993.