6 papers
PySME v1.0: improved modelling of stellar spectra for survey-scale applications
Mingjie Jian, Nikolai Piskunov, Jeff Valenti +4
Stellar abundance analysis relies on flexible, high-performance spectral synthesis. To meet these needs, we present PySME v1.0, an updated Python implementation of Spectroscopy Mad…
Revisiting Ca II Activity Indices in FGK Stars: Systematic Biases in Infrared Triplet Measurements
Xiaozhen Yang, Xiaoting Fu, Mingjie Jian +10
Synthetic-template subtraction is widely used to measure chromospheric activity in large spectroscopic surveys. However, many solar-like FGK stars show systematically negative Ca I…
Observational constraints on the origin of the elements. X. Combining NLTE and machine learning for chemical diagnostics of 4 million stars in the 4MIDABLE-HR survey
Nicholas Storm, Maria Bergemann, Tomasz RóżaÅski +9
We present the 4MOST-HR resolution Non-Local Thermal Equilibrium (NLTE) Payne artificial neural network (ANN), trained on new FGK spectra with 16 elements computed in NL…
Stellar Population Astrophysics (SPA) with the TNG 23 IR elemental abundances of 114 giant stars in 41 Open Clusters
Shilpa Bijavara Seshashayana, Henrik Jönsson, Valentina D'Orazi +4
Open clusters have been extensively used as tracers of Galactic chemical evolution, as their constituent stars possess shared characteristics, including age, Galactocentric radius,…
Stellar population astrophysics (SPA) with the TNG. The Phosphorus abundance on the young side of MilkyWay
Mingjie Jian, Xiaoting Fu, Valentina D'Orazi +11
We present phosphorus abundance measurements for a total of 102 giant stars, including 82 stars in 24 open clusters and 20 Cepheids, based on high-resolution near-infrared spectra…
Optical spectroscopic signatures of the red giant evolutionary state
Ella Xi Wang, Melissa Ness, Thomas Nordlander +17
Modern spectroscopic surveys output large data volumes. Theoretical models provide a means to transform the information encoded in these data to measurements of physical stellar pr…