The end of star formation in Chamaeleon I ? A LABOCA census of starless and protostellar cores

Abstract

Chamaeleon I is the most active region in terms of star formation in the Chamaeleon molecular cloud complex. Its population of prestellar and protostellar cores is not known and a controversy exists concerning its history of star formation. Our goal is to characterize the earliest stages of star formation in this cloud. We used the bolometer array LABOCA at APEX to map the cloud in dust continuum emission at 870 micron. The detected sources are analysed by carefully taking into account the spatial filtering inherent in the data reduction process. A search for associations with YSOs is performed using Spitzer data and the SIMBAD database. Most of the detected 870 micron emission is distributed in 5 filaments. We identify 59 starless cores, one candidate first hydrostatic core, and 21 sources associated with more evolved YSOs. The starless cores are only found above a visual extinction threshold of 5 mag. They are less dense than those detected in other nearby molecular clouds by a factor of a few on average. The core mass distribution is consistent with the IMF at the high-mass end but is overpopulated at the low-mass end. In addition, at most 17% of the cores have a mass larger than the critical Bonnor-Ebert mass. Both results suggest that a large fraction of the starless cores may not be prestellar. Based on the census of prestellar cores, Class 0 protostars, and more evolved YSOs, we conclude that the star formation rate has decreased with time in this cloud. The low fraction of candidate prestellar cores among the population of starless cores, the small number of Class 0 protostars, the high global star formation efficiency, the decrease of the star formation rate with time, and the low mass per unit length of the detected filaments all suggest that we may be witnessing the end of the star formation process in Cha I {abridged}.

Accepted for publication in A&A. 35 pages, 17 figures, 13 tables. A version with high-resolution figures is available on request to the first author

References in corpus (13)

• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• Observing the gas temperature drop in the high-density nucleus of L 1544
• The Stellar Population of the Chamaeleon I Star-Forming Region
• Bolocam Survey for 1.1 mm Dust Continuum Emission in the c2d Legacy Clouds. II. Ophiuchus
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• Comparing Star Formation on Large Scales in the c2d Legacy Clouds: Bolocam 1.1 mm Dust Continuum Surveys of Serpens, Perseus, and Ophiuchus
• Depletion and low gas temperature in the L183 prestellar core : the N2H+ - N2D+ tool
• Current Star Formation in the Perseus Molecular Cloud: Constraints from Unbiased Submillimeter and Mid-Infrared Surveys
• New Low-Mass Stars and Brown Dwarfs with Disks in the Chamaeleon I Star-Forming Region
• SCUBA and Spitzer observations of the Taurus molecular cloud - pulling the bull's tail
• The evolutionary state of the southern dense core Cha-MMS1
• Large grains in disks around young stars: ATCA observations of WW Cha, RU Lup, and CS Cha
• Distances to nearby molecular clouds and star forming regions.III. Localizing extinction jumps with a Hipparcos calibration of 2mass photometry

Cited by in corpus (12)

• An Ice Age JWST inventory of dense molecular cloud ices
• Herschel's view of the large-scale structure in the Chamaeleon dark clouds
• Far-infrared to millimeter data of protoplanetary disks: dust growth in the Taurus, Ophiuchus, and Chamaeleon I star-forming regions
• Low EUV Luminosities Impinging on Protoplanetary Disks
• Massive 70 micron quiet clumps II: non-thermal motions driven by gravity in massive star formation?
• Accretion Phase of Star Formation in Clouds with Different Metallicities
• The Circumnuclear Disk Revealed by ALMA. I. Dense Clouds and Tides in the Galactic Center
• BoA: a versatile software for bolometer data reduction
• A centrally concentrated sub-solar mass starless core in the Taurus L1495 filamentary complex
• The Herschel view of circumstellar discs: a multi-wavelength study of Chamaeleon I
• Asteroseismology of red giant stars
• The GRAVITY young stellar object survey V. The orbit of the T Tauri binary star WW Cha