Related papers: Chamaeleon
In the scope of the star formation process, it is unclear how the environment shapes the initial mass function (IMF). While observations of open clusters propose a universal picture for the IMF from the substellar domain up to a few solar…
Circumstellar disks are expected to be the birthplaces of planets. The potential for forming one or more planets of various masses is essentially driven by the initial mass of the disks. We present and analyze Herschel/PACS observations of…
Based on high-resolution UVES spectra we found that the radial velocity (RV) dispersion of nine of twelve known young bona fide and candidate brown dwarfs in the Cha I dark cloud is 2.0 km/s, i.e. significantly smaller than the RV…
We present high-resolution (FWHM ~ 0.3-1.5 km/s) spectra of interstellar Ca I absorption toward 30 Galactic stars. Comparisons of the column densities of Ca I, Ca II, K I, and other species -- for individual components identified in the…
We present the results of a HST WFPC2 search for substellar companions to members of the star-forming cluster IC 348. The detection limits for companions to low-mass stars and brown dwarfs in the PC images are dm_791=0, 2.5, and 5.5 at…
We revisit the published analyses of ROSAT X-ray observations of the star forming regions NGC 2264 and Chamaeleon I (~3 and ~5 Myr old respectively) in the light of newly published optical data. At odds with previous results on Chamaeleon I…
The observations of microlensing events in the Large Magellanic Cloud suggest that a sizable fraction (\sim 50%) of the galactic halo is in the form of MACHOs (Massive Astrophysical Compact Halo Objects) with an average mass $\sim 0.27…
In our ongoing search for close and faint companions around T Tauri stars, we found a very faint (Ks=14.9mag, Ks_0=14.4mag) object, just ~2.67" northwest of the Chamaeleon star-forming region member CT Cha corresponding to a projected…
Infrared Dark Clouds (IRDCs) are dense molecular clouds seen as extinction features against the bright mid-infrared Galactic background. Millimeter continuum maps toward 38 IRDCs reveal extended cold dust emission to be associated with each…
The early-K star T Cha, a member of the relatively nearby (D ~ 100 pc) epsilon Cha Association, is a relatively "old" (age ~7 Myr) T Tauri star that is still sporadically accreting from an orbiting disk whose inner regions are evidently now…
Brown dwarfs -- substellar bodies more massive than planets but not massive enough to initiate the sustained hydrogen fusion that powers self-luminous stars -- are born hot and slowly cool as they age. As they cool below about 2,300 K,…
We report a Fermi-LAT $\gamma$-ray analysis for the Chamaeleon molecular-cloud complex using a total column density (NH) model based on the dust optical depth at 353 GHz ($\tau_{353}$) with the Planck thermal dust emission model. Gamma rays…
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.…
We report new results in our continuing study of the unique compact (1 pc extent), nearby (d = 97 pc), young (t = 9 Myr) stellar cluster dominated by the B9 star eta Chamaeleontis. An optical photometric survey spanning 1.3 x 1.3 pc adds…
Observations are presented of emission lines from organic molecules at frequencies 32 - 50 GHz in the vicinity of Chamaeleon MMS1. This chemically-rich dense cloud core habours an extremely young, very low-luminosity protostellar object and…
We investigated the giant molecular clouds (GMCs) in M74 (NGC 628), using data obtained from the PHANGS project. We applied the GMC Types according to the activity of star formation: Type I without star formation, Type II with H$\alpha$…
A quantitative interpretation of the observed relation between the interstellar linear polarization curve parameters $K$ and $\lambda_{\max}$ characterizing the width and the wavelength of a polarization maximum, respectively, is given. The…
We present the results of a Near-Infrared deep photometric survey of a sample of six embedded star clusters in the Vela-D molecular cloud, all associated with luminous (~10^3 Lsun) IRAS sources. The clusters are unlikely to be older than a…
Context: Core accretion models of massive star formation require the existence of massive, starless cores within molecular clouds. Yet, only a small number of candidates for such truly massive, monolithic cores are currently known. Aims:…
SONYC - Substellar Objects in Nearby Young Clusters - is a survey program to investigate the frequency and properties of substellar objects with masses down to a few times that of Jupiter in nearby star-forming regions. In this third paper,…