Spectroscopy of Very Low Mass Stars and Brown Dwarfs in the Lambda Orionis Star Forming Region

Abstract

Context. Most observational studies so far point towards brown dwarfs sharing a similar formation mechanism as the one accepted for low mass stars. However, larger databases and more systematic studies are needed before strong conclusions can be reached. Aims. In this second paper of a series devoted to the study of the spectroscopic properties of the members of the Lambda Orionis Star Forming Region, we study accretion, activity and rotation for a wide set of spectroscopically confirmed members of the central star cluster Collinder 69 to draw analogies and/or differences between the brown dwarf and stellar populations of this cluster. Moreover, we present comparisons with other star forming regions of similar and different ages to address environmental effects on our conclusions. Methods. We study prominent photospheric lines to derive rotational velocities and emission lines to distinguish between accretion processes and chromospheric activity. In addition, we include information about disk presence and X-ray emission. Results. We report very large differences in the disk fractions of low mass stars and brown dwarfs (~58%) when compared to higher mass stars (26+4-3%) with 0.6 Msun being the critical mass we find for this dichotomy. As a byproduct, we address the implications of the spatial distribution of disk and diskless members in the formation scenario of the cluster itself. We have used the Halpha emission to discriminate among accreting and non-accreting sources finding that 38+8-7% of sources harboring disks undergo active accretion and that his percentage stays similar in the substellar regime. For those sources we have estimated accretion rates. Finally, regarding rotational velocities, we find a high dispersion in vsin(i) which is even larger among the diskless population.

Accepted for publication in A&A. 18 figs including the Appendix and an online table

References in corpus (12)

• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
• The Disk Around CoKu Tau/4: Circumbinary, not Transitional
• A Spitzer c2d Legacy Survey to Identify and Characterize Disks with Inner Dust Holes
• A companion candidate in the gap of the T Cha transitional disk
• Spectroscopy of Very Low Mass Stars and Brown Dwarfs in the Lambda Orionis Star Forming Region. I. Enlarging the census down to the planetary mass domain in Collinder 69
• FLAMES spectroscopy of low-mass stars in the young clusters sigma Ori and lambda Ori
• U-band study of the accretion properties in the sigma Ori star-forming region
• A survey for low mass spectroscopic binary stars in the young clusters around sigma Orionis and lambda Orionis
• SPITZER: Accretion in Low Mass Stars and Brown Dwarfs in the Lambda Orionis Cluster
• XMM-Newton investigations of the Lambda Orionis star-forming region (XILO). I. The young cluster Collinder 69
• XMM-Newton observations of the young open cluster around lambda Orionis

Cited by in corpus (45)

• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• X-Shooter spectroscopy of young stellar objects: IV -- Accretion in low-mass stars and sub-stellar objects in Lupus
• Pre-main-sequence isochrones -- II. Revising star and planet formation timescales
• X-Shooter study of accretion in Chamaeleon I: II. A steeper increase of accretion with stellar mass for very low mass stars?
• The Gaia-ESO Survey: Chromospheric Emission, Accretion Properties, and Rotation in $\gamma$ Velorum and Chamaeleon I
• Self-consistent evolution of accreting low-mass stars and brown dwarfs
• Orion revisited. II. The foreground population to Orion A
• Calibration of the Halpha Age-Activity relation for M dwarfs
• The optical+infrared L dwarf spectral sequence of young planetary-mass objects in the Upper Scorpius association
• OTS44: Disk and accretion at the planetary border
• Gas and dust in the TW Hydrae Association as seen by the Herschel Space Observatory
• Explaining the luminosity spread in young clusters: proto and pre-main sequence stellar evolution in a molecular cloud environment
• Radiation hydrodynamics simulations of protoplanetary disks: Stellar mass dependence of the disk photoevaporation rate
• BANYAN. VIII. New Low-Mass Stars and Brown Dwarfs with Candidate Circumstellar Disks
• Population study on MHD wind-driven disc evolution -- Confronting theory and observation
• Planck cold clumps in the $\lambda$ Orionis complex: I. Discovery of an extremely young Class 0 protostellar object and a proto-brown dwarf candidate in a bright rimmed clump PGCC G192.32-11.88
• First millimeter detection of the disk around a young, isolated, planetary-mass object
• The APOGEE-2 Survey of the Orion Star Forming Complex: I. Target Selection and Validation with early observations
• Dust clearing by radial drift in evolving protoplanetary discs
• A new take on the low-mass brown dwarf companions on wide-orbits in Upper-Scorpius
• Age Spreads and Systematics in λ Orionis with Gaia DR2 and the SPOTS tracks
• Towards a population synthesis of discs and planets. II. Confronting disc models and observations at the population level
• The seven sisters DANCe.II. Proper motions and the lithium-rotation-activity connection for G and K Pleiads
• The Herschel/PACS view of disks around low-mass stars in Chamaleon-I
• Disk Masses and Dust Evolution of Protoplanetary Disks Around Brown Dwarfs
• Characterizing the morphology of the debris disk around the low-mass star GSC~07396-00759
• A homogeneous analysis of disks around brown dwarfs
• Spectral energy distribution of M-subdwarfs: A study of their atmospheric properties
• The Gaia-ESO Survey: Constraining evolutionary models and ages for young low mass stars with measurements of lithium depletion and rotation
• Physical parameters of late M-type members of Chamaleon I and TW Hydrae Association: Dust settling, age dispersion and activity
• ABYSS I: Targeting strategy for APOGEE & BOSS young star survey in SDSS-V
• Rapid-then-slow migration reproduces mass distribution of TRAPPIST-1 system
• Using binary statistics in Taurus-Auriga to distinguish between brown dwarf formation processes
• Clusters: age scales for stellar physics
• Herschel -PACS observations of [OI] and H2O in Cha II
• The NEMESIS Catalogue of Young Stellar Objects for the Orion Star Formation Complex. I. General description of data curation
• Gas disk interactions, tides and relativistic effects in the rocky planet formation at the substellar mass limit
• Investigation of Rocket Effect in BRC 18 using Gaia EDR3
• Giant planet formation via pebble accretion across different stellar masses
• On the diversification and dissipation of protoplanetary disks
• The effect of stellar evolution on dispersal of protoplanetary disks: Disk fraction in star-forming regions
• Optical polarimetry study of Lambda-Orionis star-forming region
• The dispersal of protoplanetary discs -- III: Influence of stellar mass on disc photoevaporation
• Substellar candidates at the earliest stages: the SUCANES database
• The role of inner disk edges in shaping ultra-short-period planet systems around late M dwarfs