The dust temperatures of the prestellar cores in the rho Oph main cloud and in other star forming regions: consequences for the core mass function

Abstract

We estimate the dust temperatures of the clumps in the rho Oph main cloud taking into account the 3D geometry of the region, and external heating from the interstellar radiation field and from HD147879,a nearby luminous B2V star, which is believed to dominate the radiation field in the region. We find that the regions where prestellar cores are observed (i.e. at optical visual extinctions >7 mag) are colder than ~10-11K. These dust temperatures are smaller than those which previous studies of the same region have assumed. We use the new dust temperatures to estimate the masses of the prestellar cores in the rho Oph main cloud from mm observations, and we find core masses that are larger than previous estimates by a factor of ~2-3. This affects the core mass function (CMF) of the region; we find that the mass at which the core mass spectrum steepens from a slope alpha~1.5 to a slope alpha~2.5 has moved from ~0.5 Msun to ~1Msun. In contrast with the CMF in other star forming regions (e.g. Orion), there is no indication for a turnover down to the completeness limit (~0.2Msun), but the CMF may flatten at around ~0.4Msun. We generalize our results to the prestellar cores in Taurus and in Orion. In Taurus the ambient radiation field heating the prestellar cores is believed to be weaker than than that in rho Oph. Hence, the dust temperatures of the cores in Taurus are expected to be below ~ 10-11 K.In Orion the radiation field is believed to be 10^3 times stronger than the standard interstellar radiation field. Based on this assumption we estimate that the dust temperatures of the prestellar cores in Orion are around ~20-30K.

MNRAS accepted

References in corpus (5)

• The COMPLETE Survey of Star-Forming Regions: Phase I Data
• The Large and Small Scale Structures of Dust in the Star-Forming Perseus Molecular Cloud
• A SCUBA survey of Orion, the low-mass end of the core mass function
• A SCUBA survey of L1689 - The dog that didn't bark
• The Effect of Noise in Dust Emission Maps on the Derivation of Column Density, Temperature and Emissivity Spectral Index

Cited by in corpus (10)

• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• Multiple protostellar systems. II. A high resolution near-infrared imaging survey in nearby star-forming regions
• Interferometric Identification of a Pre-Brown Dwarf
• The initial conditions of star formation VIII: an observational study of the Ophiuchus cloud L1688 and implications for the prestellar core mass function
• The JCMT BISTRO Survey: The Magnetic Field In The Starless Core $\rho$ Ophiuchus C
• The JCMT and Herschel Gould Belt Surveys: A comparison of SCUBA-2 and Herschel data of dense cores in the Taurus dark cloud L1495
• The Green Bank Ammonia Survey: A Virial Analysis of Gould Belt Clouds in Data Release 1
• The census of dense cores in the Serpens region from the Herschel Gould Belt Survey
• Intensity-Corrected Herschel Observations of Nearby Isolated Low-Mass Clouds
• Will ALMA Reveal the True Core Mass Function of Protoclusters?