Chamaeleon cloud complex

Contents

Chamaeleon cloud complex The Chamaeleon cloud complex is a nearby southern-sky molecular cloud complex associated with active low-mass star formation in the constellation Chamaeleon. It is studied across electromagnetic regimes by observatories such as European Southern Observatory, NASA, Atacama Large Millimeter/submillimeter Array, and missions including ROSAT, Spitzer Space Telescope, and Herschel Space Observatory. The complex is a benchmark target for research groups at institutions like Max Planck Society, Harvard–Smithsonian Center for Astrophysics, National Aeronautics and Space Administration, and Centre National de la Recherche Scientifique.

Overview

The Chamaeleon complex comprises multiple dark clouds mapped in surveys by teams from Mount Wilson Observatory, Anglo-Australian Observatory, and Cerro Tololo Inter-American Observatory and appears in catalogues compiled by projects such as the Two Micron All Sky Survey and the Infrared Astronomical Satellite. It lies in the southern hemisphere near objects observed by explorers like James Cook and was included in early photographic atlases by Henry Draper. The complex provides an environment for comparisons to regions such as Taurus Molecular Cloud, Ophiuchus cloud complex, Perseus molecular cloud, Orion Nebula, and Rho Ophiuchi cloud complex.

The complex is commonly partitioned into subregions historically named Chamaeleon I, Chamaeleon II, and Chamaeleon III in catalogues produced by teams at European Southern Observatory and compiled into atlases by Royal Astronomical Society. Radio and submillimeter mapping by groups from Jet Propulsion Laboratory, Max Planck Institute for Astronomy, and National Radio Astronomy Observatory trace filamentary structures comparable to those in Polaris Flare and Pipe Nebula. Dense cores within the complex have been identified in surveys by James Clerk Maxwell Telescope, Institut de Radioastronomie Millimétrique, and Harvard University teams, and are catalogued alongside objects from the Rosette Nebula and Lupus molecular cloud studies.

Chamaeleon hosts populations of young stellar objects identified by memberships assigned by research groups at University of California, European Southern Observatory, and Smithsonian Astrophysical Observatory. Pre-main-sequence stars here are compared with samples from IC 348, NGC 1333, and T Tauri populations studied by observers at California Institute of Technology and Stanford University. Brown dwarfs and very low-mass stars in Chamaeleon have been characterized in work connected to European Space Agency missions and teams at Max Planck Institute for Astronomy and University of Cambridge. Accretion and disk signatures have been analyzed using data from Spitzer Space Telescope, ALMA, and Very Large Telescope programs led by groups affiliated with National Science Foundation and Australian National University.

Studies of molecular tracers such as CO, C18O, and NH3 use facilities including Atacama Pathfinder Experiment, Institut de Radioastronomie Millimétrique, and Nobeyama Radio Observatory, with chemical modeling by researchers at Princeton University and University of Bonn. Dust emission and extinction mapping have been produced with instruments from Herschel Space Observatory, Planck (spacecraft), and the Infrared Astronomical Satellite, with opacity laws compared to results for Cepheus Flare and Monoceros R2. Isotopic ratios and depletion patterns are discussed in analyses by teams at University of Leiden and Max Planck Institute for Extraterrestrial Physics.

Parallax and proper motion measurements from Gaia (spacecraft) and earlier astrometric campaigns at Hipparcos set the distance scale near 160–180 parsecs, refined by studies affiliated with University of Cambridge, European Southern Observatory, and Max Planck Society. Radial velocity surveys using instruments at European Southern Observatory and Anglo-Australian Telescope reveal kinematic substructure comparable to that seen in Lupus (constellation) and Scorpius–Centaurus OB association. The complex’s motions are discussed in the context of large-scale features studied by research teams at NASA, Jet Propulsion Laboratory, and National Radio Astronomy Observatory.

Major observational efforts include infrared surveys by Spitzer Space Telescope and WISE, X-ray studies by ROSAT and XMM-Newton, and millimeter mapping by ALMA and Atacama Large Millimeter/submillimeter Array precursor programs. Cataloguing and data release work has been carried out by collaborations involving Two Micron All Sky Survey, Sloan Digital Sky Survey, and ESA archives, with follow-up spectroscopy from European Southern Observatory instruments and the Keck Observatory. Complementary theoretical modeling has been published by groups at Princeton University, Harvard University, and University of Chicago.

Key subregions include Chamaeleon I, a site of concentrated star formation studied by teams at ESO, Harvard–Smithsonian Center for Astrophysics, and Max Planck Institute for Astronomy; Chamaeleon II, often targeted in surveys by Spitzer Space Telescope and Herschel Space Observatory; and the more quiescent Chamaeleon III examined in CO mapping programs by IRAM and NRAO. Notable young stars, protostars, and brown dwarfs have been catalogued by researchers at University of Arizona, California Institute of Technology, and University of Exeter, and individual sources are frequently cross-referenced with objects in catalogues curated by SIMBAD, VizieR, and observatory archives at European Southern Observatory.

Category:Star-forming regions