Ced 112

Ced 112
Name	Ced 112
Type	Reflection nebula complex
Epoch	J2000
Constellation	Chamaeleon
Distance	~160–200 pc
Identifiers	Ced 112, Cederblad 112, IRAS 11187-7620, GCCG 4

Ced 112 is a reflection nebula complex and embedded star-forming region located in the Chamaeleon molecular cloud complex. It appears as a bright reflection structure illuminated by young intermediate-mass stars and associated pre-main-sequence objects, and it occupies part of a larger dark cloud system mapped in optical, infrared, and radio surveys. Ced 112 plays a role in studies of protostellar evolution, circumstellar disks, and clustered star formation within nearby southern-hemisphere molecular clouds.

Identification and Nomenclature

Ced 112 is cataloged in the Cederblad catalog of reflection nebulae compiled by Syed Cederblad and subsequently cross-identified with far-infrared and radio surveys such as the Infrared Astronomical Satellite (IRAS) source IRAS 11187-7620 and entries in surveys by the Two Micron All Sky Survey (2MASS) and the Spitzer Space Telescope imaging programs. It is associated with star designations found in pre-main-sequence catalogs including T Tauri lists and with bright Herbig Ae/Be candidates indexed in studies by George Herbig. Observers have referred to the region in catalogs from the European Southern Observatory (ESO) and in molecular-line compilations by groups at institutions such as the Max Planck Institute for Astronomy and the Harvard-Smithsonian Center for Astrophysics.

Location and Observational Data

Ced 112 lies within the Chamaeleon I and II complex region near well-known objects such as the dark cloud L1688 analogs and the nebulous environs studied in the southern sky alongside objects like R Coronae Australis and the Lupus clouds. Coordinates (J2000) place Ced 112 in the constellation Chamaeleon, nearby cataloged infrared sources and optical reflection patches recorded in surveys by the Anglo-Australian Observatory and the Cerro Tololo Inter-American Observatory. Ced 112 has been observed across wavelengths by the Herschel Space Observatory, the Spitzer Space Telescope, the Atacama Pathfinder Experiment (APEX), and millimeter interferometers including the Atacama Large Millimeter/submillimeter Array (ALMA), yielding photometry, spectroscopy, and high-resolution imaging. Photometric datasets available include near-infrared photometry from 2MASS, mid-infrared imaging from Spitzer's IRAC and MIPS, and far-infrared mapping from Herschel's PACS and SPIRE instruments.

Physical Characteristics

The nebular structure of Ced 112 displays scattering-dominated spectra characteristic of reflection nebulae, with prominent dust-scattered continuum and subdued emission lines relative to ionized H II regions such as Orion Nebula (M42) or Trifid Nebula (M20). Its dust properties, derived from spectral energy distributions and submillimeter continuum maps, reveal cold grains with temperatures typically below those found in massive-star regions like Carina Nebula; measured opacities and emissivity indices have been compared to values determined in studies of Taurus Molecular Cloud and Perseus molecular cloud. Molecular-line surveys targeting CO isotopologues, CS, and HCO+ show dense clumps and filamentary structures analogous to filaments in Aquila Rift and IC 5146, with column densities sufficient to shield embedded protostars from external radiation fields produced by stars such as those in Sco-Cen OB association.

Stellar Content and Nebular Features

Ced 112 hosts a mixed population of pre-main-sequence objects including classical and weak-lined T Tauri stars, candidate Herbig Ae/Be stars, and embedded protostellar cores identified through infrared excesses and millimeter continuum sources. Cataloged young stellar objects (YSOs) in the field have been cross-matched with samples from Gaia astrometry to refine membership and kinematics, in a manner similar to studies of YSOs in Chamaeleon I, IC 348, and NGC 1333. Scattered-light nebulae, reflection arcs, and variable illumination features have been reported and compared with time-variable phenomena seen in objects like HH 30 and the variable nebulae illuminated by R Monocerotis. Outflows and Herbig-Haro objects associated with Ced 112 resemble jet-driven shocks cataloged in surveys of Orion and L1551, with molecular outflow signatures detected in CO consistent with early-stage accretion activity described in reviews by Phil Armitage and Paola D'Alessio.

Distance, Age, and Environmental Context

Distance estimates for Ced 112 place it within the broader Chamaeleon complex at roughly 160–200 parsecs, comparable to distances derived for Chamaeleon I and proximate clouds measured by Hipparcos and refined by Gaia parallaxes. Age estimates for the stellar population span a few 10^5 to a few 10^6 years, aligning Ced 112 with young clusters such as Chamaeleon I cluster and contrasting with older nearby associations like TW Hydrae Association. The local interstellar environment includes interactions with larger-scale filaments and magnetic-field-aligned structures studied with polarization experiments by groups at IRAM and the Submillimeter Array; comparisons have been made to environmental conditioning in regions like Serpens South and Pipe Nebula.

Research History and Notable Studies

Ced 112 was first noted in optical reflection surveys compiled by Syed Cederblad and later became a target in IRAS-based investigations of southern star-forming regions during the 1980s. Subsequent studies using facilities such as the ESO New Technology Telescope, Spitzer, and Herschel focused on YSO census, spectral energy distributions, and dust-mass determinations, citing methodologies used in analyses of Taurus and Perseus. More recent work leveraging ALMA and Gaia has refined protostellar multiplicity, kinematics, and disk properties, echoing approaches of surveys like the Orion Protostar Survey and the Disk Substructures at High Angular Resolution Project. Ongoing observations aim to link small-scale disk evolution with cloud-scale fragmentation processes discussed in theoretical frameworks by Christopher McKee and Shantanu Basu.

Category:Reflection nebulae Category:Star-forming regions Category:Chamaeleon constellation