DOI

  • Rebeca Garcia Lopez
  • Ryuichi Kurosawa
  • Alessio Garatti o Carattio
  • Alexander Kreplin
  • Gerd Weigelt
  • Larisa V. Tambovtseva
  • Vladimir P. Grinin
  • Thomas P. Ray

The origin of the near-infrared (NIR) HI emission lines in young stellar objects are not yet understood. To probe it, we present multi-epoch LBT-LUCIFER spectroscopic observations of the Paδ, Paβ, and Brγ lines observed in the Herbig star VV Ser, along with Very Large Telescope Interferometer-AMBER Br? spectro-interferometric observations at medium resolution. Our spectroscopic observations show line profile variability in all the HI lines. The strongest variability is observed in the redshifted part of the line profiles. The Br? spectrointerferometric observations indicate that the Br? line emitting region is smaller than the continuum emitting region. To interpret our results, we employed radiative transfer models with three different flow configurations: magnetospheric accretion, a magnetocentrifugally driven disc wind, and a schematic bipolar outflow. Our models suggest that the HI line emission inVVSer is dominated by the contribution of an extended wind, perhaps a bipolar outflow. Although the exact physical process for producing such outflow is not known, this model is capable of reproducing the averaged single-peaked line profiles of the HI lines. Additionally, the observed visibilities, differential and closure phases are best reproduced when a wind is considered. Nevertheless, the complex line profiles and variability could be explained by changes in the relative contribution of the magnetosphere and/or winds to the line emission. This might indicate that the NIR HI lines are formed in a complex inner disc region where inflow and outflow components might coexist. Furthermore, the contribution of each of these mechanisms to the line appears time variable, suggesting a non-steady accretion/ejection flow.

Original languageEnglish
Pages (from-to)156-170
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume456
Issue number1
DOIs
StatePublished - 11 Feb 2016

    Research areas

  • Circumstellar matter, Infrared: stars, Stars: protostars, Stars: variables: T Tauri, Herbig Ae/Be, Stars: winds, outflows, Techniques: interferometric

    Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

ID: 87426134