Magnetospheres and Disk Accretion in Herbig Ae/Be Stars

By J. Muzerolle, P. D’Alessio, N. Calvet, L. Hartmann. 2004

191 citations recorded by the source corpus.

We present evidence of magnetically mediated disk accretion in Herbig Ae/Be stars. Magnetospheric accretion models of Balmer and sodium profiles calculated with appropriate stellar and rotational parameters are in qualitative agreement with the observed profiles of the Herbig Ae star UX Ori and yield a mass accretion rate of ~10-8 M☉ yr-1. If more recent indications of an extremely large rotation rate for this object are correct, the magnetic field geometry must deviate from that of a standard dipole in order to produce line emission consistent with observed flux levels. Models of the associated accretion shock qualitatively explain the observed distribution of excess fluxes in the Balmer discontinuity for a large ensemble of Herbig Ae/Be stars and imply typically small mass accretion rates, ≲10-7 M☉ yr-1. In order for accretion to proceed onto the star, significant amounts of gas must exist inside the dust destruction radius, which is potentially problematic for recently advocated scenarios of "puffed" inner dust wall geometries. However, our models of the inner gas disk show that for the typical accretion rates we have derived, the gas should generally be optically thin, thus allowing direct stellar irradiation of the inner dust edge of the disk.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/12933b42ef398c650e8a40bfdd76f82475a1d809

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In Astronomy and Astrophysics

1. K. Luhman
2. L. Hartmann
3. G. Herczeg
4. N. Calvet
5. S. Andrews
6. L. Testi
7. A. Natta
8. C. Dullemond

Citations in the corpus

• The shape of the inner rim in proto-planetary disks (2005, background): “Inside this hole, only gas may exist but as long as the gas is optically thin to the stellar radiation (Muzerolle et al. 2004) we can neglect its absorbing effect.”
• Magnetic Fields of Nondegenerate Stars (2009, background): “…indirect proxies suggest that similar processes may also be at work and th t magnetic fields could also be involved in at least a small fraction of massive stars (e.g.,the UX Ori-type objects, Muzerolle et al. 2004), conclusive and direct evidence such as that available for cTTSs is still lacking.”
• UNVEILING THE STRUCTURE OF PRE-TRANSITIONAL DISKS (2010, background): “This transition appears as a “wall” that is frontally illuminated by the star, since for typical mass accretion rates the inner disk gas is optically thin (Muzerolle et al. 2004).”
• Accretion Rates in Herbig Ae stars (2006, methodology): “Muzerolle et al. (2004) deriveda Send offprint requests to: A. Natta, natta@arcetri.astro.it similar value ofṀacc for the∼ 2 M⊙ star UX Ori by fitting its Hα profile with magnetospheric accretion models.”
• The Inner Regions of Protoplanetary Disks (2010, methodology): “Another method, employed by Muzerolle et al. (2004), is to treat the large opacity gap between 0.2 and 0.4 µm (Fig.”
• Herbig Ae/Be Stars in nearby OB Associations (2004, background): “…energy distributions (SEDs), which has been attributed to emission from an optically thick ‘‘wall’’ at the dust destruction radius, which is directly heated by the star (Natta et al. 2001; Maheswar et al. 2002; Dullemond et al. 2001; Dullemond & Dominik 2004b; Muzerolle et al. 2004, 2003b).”
• [O I] 6300 Å emission in Herbig Ae/Be systems: Signature of Keplerian rotation (2005, background): “We refer to the recent paper of Muzerolle et al. (2004) for a more elaborate discussion on this subject.”
• Accretion onto Pre-Main-Sequence Stars (2016, background): “…the ultraviolet spectra of low-mass and intermediate-mass T Tauri stars, brown dwarfs, and some Herbig Ae/Be (HAeBe) stars reasonably well (Calvet & Gullbring 1998; Gullbring et al. 2000; Ardila & Basri 2000; Muzerolle et al. 2000, 2003; Calvet 2004; Muzerolle et al. 2004; Mendigutia et al. 2011).”
• Accretion disks in luminous young stellar objects (2015, background): “19 we present a schematical version of our summary showing our knowledge of accretion disks around intermediate- (A-type) and high-mass (B- and O-type) young stars as acquired with radio/mm and optical/IR interferometry.”
• A spectroscopic survey of Herbig Ae/Be stars with X-shooter – I. Stellar parameters and accretion rates (2015, methodology): “This method of accretion-shock modelling has been successfully adapted and applied, in the majority of cases, to small sets of HAeBes in recent years (Muzerolle et al. 2004; Donehew & Brittain 2011; Mendigut́ıa et al. 2011b; Pogodin et al. 2012; Mendigut́ıa et al. 2013, 2014).”