English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We aim at characterizing the accretion properties of several hundred membersof the star-forming cluster NGC 2264 (3 Myr). We performed a deep u,g,r,imapping and a simultaneous u+r monitoring of the region with CFHT/MegaCam inorder to directly probe the accretion process from UV excess measurements.Photometric properties and stellar parameters are determined homogeneously forabout 750 monitored young objects, spanning the mass range 0.1-2 Mo. About 40%are classical (accreting) T Tauri stars, based on various diagnostics (H_alpha,UV and IR excesses). The remaining non-accreting members define the(photospheric+chromospheric) reference UV emission level over which flux excessis detected and measured. We revise the membership status of cluster membersbased on UV accretion signatures and report a new population of 50 CTTScandidates. A large range of UV excess is measured for the CTTS population,varying from a few 0.1 to 3 mag. We convert these values to accretionluminosities and obtain mass accretion rates ranging from 1e-10 to 1e-7 Mo/yr.Taking into account a mass-dependent detection threshold for weakly accretingobjects, we find a >6sigma correlation between mass accretion rate and stellarmass. A power-law fit, properly accounting for upper limits, yields M_acc$\propto$ M^{1.4+/-0.3}. At any given stellar mass, we find a large spread ofaccretion rates, extending over about 2 orders of magnitude. The monitoring ofthe UV excess on a timescale of a couple of weeks indicates that itsvariability typically amounts to 0.5 dex, much smaller than the observedspread. We suggest that a non-negligible age spread across the cluster mayeffectively contribute to the observed spread in accretion rates at a givenmass. In addition, different accretion mechanisms (like, e.g., short-livedaccretion bursts vs. more stable funnel-flow accretion) may be associated todifferent M_acc regimes.

Mapping accretion and its variability in the young open cluster NGC 2264: a study based on u-band photometry