AuthorManara, C. F.
Herczeg, G. J.
Alcalá, J. M.
Mulders, G. D.
AffiliationUniv Arizona, Lunar & Planetary Lab
Keywordsstars: pre-main sequence
stars: variables: T Tauri, Herbig Ae/Be
accretion, accretion disks
open clusters and associations: individual: Chamaeleon I
MetadataShow full item record
PublisherEDP SCIENCES S A
CitationX-shooter study of accretion in Chamaeleon I 2017, 604:A127 Astronomy & Astrophysics
JournalAstronomy & Astrophysics
Rights© ESO, 2017
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractThe dependence of the mass accretion rate on the stellar properties is a key constraint for star formation and disk evolution studies. Here we present a study of a sample of stars in the Chamaeleon I star-forming region carried out using spectra taken with the ESO VLT/X-shooter spectrograph. The sample is nearly complete down to stellar masses (M-star) similar to 0.1 M-circle dot for the young stars still harboring a disk in this region. We derive the stellar and accretion parameters using a self-consistent method to fit the broadband flux-calibrated medium resolution spectrum. The correlation between accretion luminosity to stellar luminosity, and of mass accretion rate to stellar mass in the logarithmic plane yields slopes of 1.9 +/- 0.1 and 2.3 +/- 0.3, respectively. These slopes and the accretion rates are consistent with previous results in various star-forming regions and with different theoretical frameworks. However, we find that a broken power-law fit, with a steeper slope for stellar luminosity lower than similar to 0.45 L-circle dot and for stellar masses lower than similar to 0.3 M-circle dot is slightly preferred according to different statistical tests, but the single power-law model is not excluded. The steeper relation for lower mass stars can be interpreted as a faster evolution in the past for accretion in disks around these objects, or as different accretion regimes in different stellar mass ranges. Finally, we find two regions on the mass accretion versus stellar mass plane that are empty of objects: one region at high mass accretion rates and low stellar masses, which is related to the steeper dependence of the two parameters we derived. The second region is located just above the observational limits imposed by chromospheric emission, at M-star similar to 0.3-0.4 M-circle dot. These are typical masses where photoevaporation is known to be effective. The mass accretion rates of this region are similar to 10(-10) M-circle dot/yr, which is compatible with the value expected for photoevaporation to rapidly dissipate the inner disk.
NoteOpen access journal.
VersionFinal published version
SponsorsESO Scientific Visitor Programme; Gothenburg Centre for Advanced Studies in Science and Technology as part of the GoCAS program Origins of Habitable Planets; Italian Ministero dell'Istruzione, Universita e Ricerca through the grant Progetti Premiali 2012-iALMA [CUP C52I13000140001]; NSF Astronomy & Astrophysics Research Grant ; Science Foundation Ireland [13/ERC/I2907]; Italian Ministry of Education, Universities and Research project SIR [RBSI14ZRHR]