TY - JOUR
T1 - An Updated Line List for NUV Spectral Synthesis in Evolved Stars
T2 - Redetermination of the Beryllium Abundance in the Solar Photosphere
AU - Carlberg, Joleen K.
AU - Cunha, Katia
AU - Smith, Verne V.
AU - Nascimento, José Dias Do
N1 - Funding Information:
This work has made use of the VALD database, operated at Uppsala University, the Institute of Astronomy RAS in Moscow, and the University of Vienna. Based, in part, on data collected at Subaru Telescope and obtained from the SMOKA, which is operated by the Astronomy Data Center, National Astronomical Observatory of Japan.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/9/20
Y1 - 2018/9/20
N2 - Motivated by the desire to measure beryllium abundances in red giant stars, we have constructed a new line list for synthesizing spectra in the near-ultraviolet. Using the Sun, Arcturus, and Pollux as benchmark stars, we explore potential sources of missing continuous opacity and line absorption. Despite the inclusion of new sources of continuous opacity, fitting the ultraviolet OH lines in the solar spectrum still requires artificially inflating the continuous opacity. The red giants also require the addition of a line of unknown origin in the blue wing of the Be line at λ3131.065, and we find a good match can be made by adopting a Ti ii line with low excitation potential. The inclusion of this line does not affect the measurement of the solar Be abundance. Because the fits to all of the benchmark stars require tuning the properties of known spectral lines and including both an unknown source of additional continuous opacity and spectral lines of unknown origin, we argue that the absolute abundances of Be in stars should be interpreted with caution. Therefore, the question of whether the solar Be abundance is depleted may not yet be resolved, although our model favors minimal Be depletion in the Sun.
AB - Motivated by the desire to measure beryllium abundances in red giant stars, we have constructed a new line list for synthesizing spectra in the near-ultraviolet. Using the Sun, Arcturus, and Pollux as benchmark stars, we explore potential sources of missing continuous opacity and line absorption. Despite the inclusion of new sources of continuous opacity, fitting the ultraviolet OH lines in the solar spectrum still requires artificially inflating the continuous opacity. The red giants also require the addition of a line of unknown origin in the blue wing of the Be line at λ3131.065, and we find a good match can be made by adopting a Ti ii line with low excitation potential. The inclusion of this line does not affect the measurement of the solar Be abundance. Because the fits to all of the benchmark stars require tuning the properties of known spectral lines and including both an unknown source of additional continuous opacity and spectral lines of unknown origin, we argue that the absolute abundances of Be in stars should be interpreted with caution. Therefore, the question of whether the solar Be abundance is depleted may not yet be resolved, although our model favors minimal Be depletion in the Sun.
KW - Sun: abundances
KW - stars: abundances
KW - stars: atmospheres
KW - stars: late-type
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U2 - 10.3847/1538-4357/aad8bf
DO - 10.3847/1538-4357/aad8bf
M3 - Article
AN - SCOPUS:85053929398
SN - 0004-637X
VL - 865
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 8
ER -