Herbig Ae/Be accretion rates & mechanisms

This work presents a spectroscopic study of 163 Herbig Ae/Be stars. Amongst these, we present new data for 30 objects. Stellar parameters such as temperature, reddening, mass, luminosity, and age are homogeneously determined. Mass accretion rates are determined from H{alpha} emission line measurements. Our data is complemented with the X-Shooter sample from previous studies and we update results using Gaia DR2 parallaxes giving a total of 78 objects with homogeneously determined stellar parameters and mass accretion rates. In addition, mass accretion rates of an additional 85 HAeBes are determined. We confirm previous findings that the mass accretion rate increases as a function of stellar mass, and the existence of a different slope for lower and higher mass stars, respectively. The mass where the slope changes is determined to be 3.98^+1.37_-0.94M_{sun}_. We discuss this break in the context of different modes of disc accretion for low- and high-mass stars. Because of their similarities with T Tauri stars, we identify the accretion mechanism for the late-type Herbig stars with the Magnetospheric Accretion. The possibilities for the earlier-type stars are still open, we suggest the Boundary Layer accretion model may be a viable alternative. Finally, we investigated the mass accretion-age relationship. Even using the superior Gaia based data, it proved hard to select a large enough sub-sample to remove the mass dependence in this relationship. Yet, it would appear that the mass accretion does decline with age as expected from basic theoretical considerations.

Cone search capability for table J/MNRAS/493/234/main (Astrophysical parameters and accretion properties of Northern Herbig Ae/Be stars (Tables 2 and 3))

Cone search capability for table J/MNRAS/493/234/tablec (Astrophysical parameters and accretion properties of Herbig Ae/Be stars in Fairlamb et al. (2015MNRAS.453..976F, Cat. J/MNRAS/453/976) (Tables C1 and C2))

Cone search capability for table J/MNRAS/493/234/tabled (Accretion properties of Herbig Ae/Be stars in Vioque et al. (2018, Cat. J/A+A/620/A128))

Identifier
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/MNRAS/493/234
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/493/234
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/493/234
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/MNRAS/493/234
Provenance
Creator Wichittanakom C.; Oudmaijer R.D.; Fairlamb J.R.; Mendigutia I.,Vioque M.; Ababakr K.M.
Publisher CDS
Publication Year 2020
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy