ALMA observations of the early stages of substellar formation in the Lupus 1 and 3 molecular clouds
arXiv:2012.03985 · doi:10.1051/0004-6361/202039419
Abstract
The dominant mechanism leading to the formation of brown dwarfs (BDs) remains uncertain. The most direct keys to formation, which are obtained from younger objects (pre-BD cores and proto-BDs), are limited by the very low number statistics available. We aim to identify and characterize a set of pre- and proto-BDs as well as Class II BDs in the Lupus 1 and 3 molecular clouds to test their formation mechanism. We performed ALMA band 6 (1.3 mm) continuum observations of a selection of 64 cores previously identified from AzTEC/ASTE data (1.1 mm), along with previously known Class II BDs in the Lupus 1 and 3 molecular clouds. Surveyed archival data in the optical were used to complement these observations. We expect these ALMA observations prove efficient in detecting the youngest sources in these regions, since they probe the frequency domain at which these sources emit most of their radiation. We detected 19 sources from 15 ALMA fields. Considering all the pointings in our observing setup, the ALMA detection rate was 23% and the derived masses of the detected sources were between 0.18 and 124 . We classified these sources according to their spectral energy distribution as 5 Class II sources, 2 new Class I/0 candidats, and 12 new possible pre-BD or deeply embedded protostellar candidates. We detected a promising candidate for a Class 0/I proto-BD source and inferred the disk dust mass of a bona fide Class II BD. The pre-BD cores might be the byproduct of an ongoing process of large-scale collapse. The Class II BD disks follow the correlation between disk mass and the mass of the central object that is observed at the low-mass stellar regime. We conclude that it is highly probable that the sources in the sample are formed as a scaled-down version of low-mass star formation, although disk fragmentation may be responsible for a considerable fraction of BDs.
21 pages, 10 figures, 13 tables, 3 Appendixes. Accepted in A&A
References in corpus (38)
- New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
- X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
- A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
- The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
- Accretion in the Rho-Oph pre-main sequence stars
- Identifying the Low Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores
- The Large APEX Bolometer Camera LABOCA
- Herschel-Planck dust optical-depth and column-density maps: I. Method description and results for Orion
- Exploring brown dwarf disks: A 1.3 mm survey in Taurus
- On the gas content of transitional disks: a VLT/X-Shooter study of accretion and winds
- The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. XI. Lupus Observed With IRAC and MIPS
- Formation Scenario for Wide and Close Binary Systems
- The statistical properties of stars and their dependence on metallicity: the effects of opacity
- The potential for Earth-mass planet formation around brown dwarfs
- Brown dwarf disks with ALMA: evidence for truncated dust disks in Ophiuchus
- Brown dwarf disks with ALMA
- First Confirmed Detection of a Bipolar Molecular Outflow from a Young Brown Dwarf
- Substellar Objects in Nearby Young Clusters (SONYC) VI: The planetary-mass domain of NGC1333
- Interferometric Identification of a Pre-Brown Dwarf
- Hubble and Spitzer Observations of an Edge-on Circumstellar Disk around a Brown Dwarf
- Spectroscopy of brown dwarf candidates in IC 348 and the determination of its substellar IMF down to planetary masses
- IC348-SMM2E: a Class 0 proto-brown dwarf candidate forming as a scaled-down version of low-mass stars
- The properties of discs around planets and brown dwarfs as evidence for disc fragmentation
- X-Shooter study of accretion in -Ophiucus: very low-mass stars and brown dwarfs
- Constraining disk evolution prescriptions of planet population synthesis models with observed disk masses and accretion rates
- The optical+infrared L dwarf spectral sequence of young planetary-mass objects in the Upper Scorpius association
- Demographics of disks around young very low-mass stars and brown dwarfs in Lupus
- Formation and Collapse of Quiescent Cloud Cores Induced by Dynamic Compressions
- The Taurus Boundary of Stellar/Substellar (TBOSS) Survey II. Disk Masses from ALMA Continuum Observations
- Substellar Objects in Nearby Young Clusters (SONYC) VIII: Substellar population in Lupus 3
- Very low-luminosity Class I/Flat outflow sources in sigma Orionis
- ALMA reveals a pseudo-disc in a proto-brown dwarf
- Characterization of the known T type dwarfs towards the Sigma Orionis cluster
- A centrally concentrated sub-solar mass starless core in the Taurus L1495 filamentary complex
- CO Outflow Survey of 68 Very Low Luminosity Objects: a Search for Proto-Brown Dwarf Candidates
- A search for pre- and proto-brown dwarfs in the dark cloud Barnard 30 with ALMA
- A multi-wavelength characterization of proto-brown dwarf candidates in Serpens
- Bipolar molecular outflow of the very low-mass star Par-Lup3-4