SIMBAD references

2012ApJ...755..154M - Astrophys. J., 755, 154 (2012/August-3)

Hubble Space Telescope measures of mass accretion rates in the Orion Nebula Cluster.

MANARA C.F., ROBBERTO M., DA RIO N., LODATO G., HILLENBRAND L.A., STASSUN K.G. and SODERBLOM D.R.

Abstract (from CDS):

The present observational understanding of the evolution of the mass accretion rates ({dot}Macc) in pre-main-sequence stars is limited by the lack of accurate measurements of {dot}Macc over homogeneous and large statistical samples of young stars. Such observational effort is needed to properly constrain the theory of star formation and disk evolution. Based on Hubble Space Telescope/WFPC2 observations, we present a study of {dot}Macc for a sample of ∼700 sources in the Orion Nebula Cluster, ranging from the hydrogen-burning limit to M*∼ 2 M. We derive {dot}Macc from both the U-band excess and the Hα luminosity (L), after determining empirically both the shape of the typical accretion spectrum across the Balmer jump and the relation between the accretion luminosity (Lacc) and L, which is Lacc/L statistical sample, we are able to accurately investigate relations between {dot}Macc and the parameters of the central star such as mass and age. We clearly find {dot}Macc to increase with stellar mass and decrease over evolutionary time, but we also find strong evidence that the decay of {dot}Macc with stellar age occurs over longer timescales for more massive PMS stars. Our best-fit relation between these parameters is given by log ({dot}Macc/Myr) = (-5.12 ± 0.86) - (0.46±0.13). log (t/yr) - (5.75±1.47). log (M*/M) + (1.17±0.23). log (t/yr). log (M*/M). These results also suggest that the similarity solution model could be revised for sources with M* ≳ 0.5 M. Finally, we do not find a clear trend indicating environmental effects on the accretion properties of the sources.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - protoplanetary disks - stars: formation - stars: pre-main sequence

VizieR on-line data: <Available at CDS (J/ApJ/755/154): table2.dat table3.dat table4.dat table5.dat>

Nomenclature: Tables 2-5: [MRD2012] NNNN N=703 among (Nos 20-3258).

Simbad objects: 709

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2019.12.10-09:40:54

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