Pre-main-sequence Brackett Emitters in the APOGEE DR17 Catalog: Line Strengths and Physical Properties of Accretion Columns

Hunter Campbell, Elliott Khilfeh, Kevin R. Covey, Marina Kounkel, Richard Ballantyne, Sabrina Corey, Carlos G. Román-Zúñiga, Jesús Hernández, Ezequiel Manzo Martínez, Karla Peña Ramírez, Alexandre Roman-Lopes, Keivan G. Stassun, Guy S. Stringfellow, Jura Borissova, S. Drew Chojnowski, Valeria Ramírez-Preciado, Jinyoung Serena Kim, Javier Serna, Amelia M. Stutz, Ricardo López-ValdiviaGenaro Suárez, Jason E. Ybarra, Penélope Longa-Peña, José G. Fernández-Trincado

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Very young (t ≲ 10 Myr) stars possess strong magnetic fields that channel ionized gas from the interiors of their circumstellar disks to the surface of the star. Upon impacting the stellar surface, the shocked gas recombines and emits hydrogen spectral lines. To characterize the density and temperature of the gas within these accretion streams, we measure equivalent widths of Brackett (Br) 11-20 emission lines detected in 1101 APOGEE spectra of 326 likely pre-main-sequence accretors. For sources with multiple observations, we measure median epoch-to-epoch line strength variations of 10% in Br11 and 20% in Br20. We also fit the measured line ratios to predictions of radiative transfer models by Kwan & Fischer. We find characteristic best-fit electron densities of n e = 1011-1012 cm−3, and excitation temperatures that are inversely correlated with electron density (from T ∼ 5000 K for n e ∼ 1012 cm−3 to T ∼ 12,500 K at n e ∼ 1011 cm−3). These physical parameters are in good agreement with predictions from modeling of accretion streams that account for the hydrodynamics and radiative transfer within the accretion stream. We also present a supplementary catalog of line measurements from 9733 spectra of 4255 Brackett emission-line sources in the APOGEE Data Release 17 data set.

Original languageEnglish (US)
Article number22
JournalAstrophysical Journal
Issue number1
StatePublished - Jan 1 2023

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Pre-main-sequence Brackett Emitters in the APOGEE DR17 Catalog: Line Strengths and Physical Properties of Accretion Columns'. Together they form a unique fingerprint.

Cite this