TY - JOUR
T1 - Pre-main-sequence Brackett Emitters in the APOGEE DR17 Catalog
T2 - Line Strengths and Physical Properties of Accretion Columns
AU - Campbell, Hunter
AU - Khilfeh, Elliott
AU - Covey, Kevin R.
AU - Kounkel, Marina
AU - Ballantyne, Richard
AU - Corey, Sabrina
AU - Román-Zúñiga, Carlos G.
AU - Hernández, Jesús
AU - Martínez, Ezequiel Manzo
AU - Ramírez, Karla Peña
AU - Roman-Lopes, Alexandre
AU - Stassun, Keivan G.
AU - Stringfellow, Guy S.
AU - Borissova, Jura
AU - Chojnowski, S. Drew
AU - Ramírez-Preciado, Valeria
AU - Kim, Jinyoung Serena
AU - Serna, Javier
AU - Stutz, Amelia M.
AU - López-Valdivia, Ricardo
AU - Suárez, Genaro
AU - Ybarra, Jason E.
AU - Longa-Peña, Penélope
AU - Fernández-Trincado, José G.
N1 - Funding Information:
A.S. gratefully acknowledges support by the Fondecyt Regular (project code 1220610), and ANID BASAL projects ACE210002 and FB210003.
Funding Information:
Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org . SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Astrophysik (MPA Garching), Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observatário Nacional/MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University. This work has made use of data from the European Space Agency (ESA) mission Gaia ( https://www.cosmos.esa.int/gaia ), processed by the Gaia Data Processing and Analysis Consortium (DPAC; https://www.cosmos.esa.int/web/gaia/dpac/consortium ). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
Funding Information:
We thank John Kwan and Will Fischer for their work to calculate and distribute the line ratio predictions that made this analysis possible. We also thank the anonymous referee for a prompt and useful report which improved the analysis presented here. H.C. and E.K. acknowledge support provided by Chandra Award Number GO9-20006X issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.
Funding Information:
C.R.Z. acknowledges support from projects UNAM-DGAPA-PAPIIT 112620 and CONACYT CB2018 A1-S-9754, Mexico.
Funding Information:
K.P.R. acknowledges support from ANID FONDECYT Iniciación 11201161.
Funding Information:
We thank John Kwan and Will Fischer for their work to calculate and distribute the line ratio predictions that made this analysis possible. We also thank the anonymous referee for a prompt and useful report which improved the analysis presented here. H.C. and E.K. acknowledge support provided by Chandra Award Number GO9-20006X issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.
Funding Information:
M.K. and K.R.C. acknowledge support provided by the NSF through grant No. AST-1449476, and from the Research Corporation via a Time Domain Astrophysics Scialog award (#24217).
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2023/1/1
Y1 - 2023/1/1
N2 - 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.
AB - 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.
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U2 - 10.3847/1538-4357/aca324
DO - 10.3847/1538-4357/aca324
M3 - Article
AN - SCOPUS:85145677274
SN - 0004-637X
VL - 942
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 22
ER -