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The aim of this study is to investigate systematic chemical differentiation of molecules in regions of high mass star formation. We observed five prominent sites of high mass star formation in HCN, HNC, HCO+, their isotopes, C18O, C34S and…

Astrophysics of Galaxies · Physics 2010-11-02 I. Zinchenko , P. Caselli , L. Pirogov

The project aims to use machine learning algorithms to fit the free parameters of an isotopic scaling model to elemental observations. The processes considered are massive star nucleosynthesis, Type Ia SNe, the s-process, the r-process, and…

Instrumentation and Methods for Astrophysics · Physics 2024-03-13 Haoxuan Sun

The modeling of stellar spectra is pervasive in astronomy. Conventionally, the shapes of absorption lines are modeled by convolving thermal profiles (computed given some model stellar atmosphere and line list) with broadening kernels…

Solar and Stellar Astrophysics · Physics 2025-12-11 Michael L. Palumbo

We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes…

Cosmological N-body hydrodynamic computations following atomic and molecular chemistry (e$^-$, H, H$^+$, H$^-$, He, He$^+$, He$^{++}$, D, D$^+$, H$_2$, H$_2^+$, HD, HeH$^+$), gas cooling, star formation and production of heavy elements (C,…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Umberto Maio , Edoardo Tescari

Chemical models are routinely used to predict the atmospheric composition of exoplanets and compare it with the composition retrieved from observations, but little is known about the reliability of the calculated composition. We carried out…

Earth and Planetary Astrophysics · Physics 2025-12-03 Marcelino Agundez

Isotopologue line intensity ratios of circumstellar molecules have been widely used to trace the photospheric elemental isotopic ratios of evolved stars. However, depending on the molecular species and the physical conditions of the…

Solar and Stellar Astrophysics · Physics 2020-07-01 M. Saberi , H. Olofsson , W. H. T. Vlemmings , E. De Beck , T. Khouri , S. Ramstedt

Aim: To determine whether or not gas-phase chemical models with homogeneous and time-independent physical conditions explain the many observed molecular abundances in astrophysical sources, it is crucial to estimate the uncertainties in the…

Astrophysics · Physics 2016-08-15 Valentine Wakelam , Eric Herbst , Franck Selsis , Gérard Massacrier

Meteorological factors (MF) are crucial in day-ahead load forecasting as they significantly influence the electricity consumption behaviors of consumers. Numerous studies have incorporated MF into the load forecasting model to achieve…

Machine Learning · Computer Science 2025-01-07 Yangze Zhou , Guoxin Lin , Gonghao Zhang , Yi Wang

The metal content of a galaxy is a key property for distinguishing between viable galaxy evolutionary scenarios, and it strongly influences many of the physical processes in the interstellar medium. An absolute and robust determination of…

Besides accuracy, recent studies on machine learning models have been addressing the question on how the obtained results can be interpreted. Indeed, while complex machine learning models are able to provide very good results in terms of…

Machine Learning · Computer Science 2022-11-07 Guilherme Dean Pelegrina , Leonardo Tomazeli Duarte , Michel Grabisch

Planetary nebulae are the products of the evolution of low and intermediate mass stars. The chemical property studies of these objects give important information about the elemental abundances as He, O, Ne, Ar, S and their modifications…

Solar and Stellar Astrophysics · Physics 2016-12-13 O. Cavichia , R. D. D. Costa , W. J. Maciel , M. Mollá

A stochastic model of the chemical enrichment of metal-poor systems by core-collapse supernovae is used to study the scatter in stellar abundance ratios. The resulting scatter in abundance ratios, e.g. as functions of the overall…

Astrophysics · Physics 2009-11-11 T. Karlsson , B. Gustafsson

We present detailed thermal and gas-phase chemical models for the envelope of the massive star-forming region AFGL 2591. Time- and space-dependent chemistry are used to study the physical structure proposed by van der Tak et al. (1999;…

Astrophysics · Physics 2009-11-07 S. D. Doty , E. F. van Dishoeck , F. F. S. van der Tak , A. M. S. Boonman

Reactive chemistry of molecular hydrogen at surfaces, notably dissociative sticking and hydrogen evolution, plays a crucial role in energy storage and fuel cells. Theoretical studies can help to decipher underlying mechanisms and reaction…

Upcoming 21cm surveys will map the spatial distribution of cosmic neutral hydrogen (HI) over unprecedented volumes. Mock catalogues are needed to fully exploit the potential of these surveys. Standard techniques employed to create these…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-02 Digvijay Wadekar , Francisco Villaescusa-Navarro , Shirley Ho , Laurence Perreault-Levasseur

Subhalo abundance matching (SHAM) is a popular technique for assigning galaxy mass or luminosity to haloes produced in N-body simulations. The method works by matching the cumulative number functions of the galaxy and halo properties, and…

Astrophysics of Galaxies · Physics 2021-11-02 Richard Stiskalek , Harry Desmond , Thomas Holvey , Michael G. Jones

Understanding stellar composition is fundamental not only to our comprehension of the galaxy, especially chemical evolution, but it can also shed light on the interior structure and mineralogy of exoplanets, which are formed from the same…

Earth and Planetary Astrophysics · Physics 2022-11-30 Natalie R. Hinkel , Patrick A. Young , Caleb H. Wheeler

We design and train a neural network (NN) model to efficiently predict the infrared spectra of interstellar polycyclic aromatic hydrocarbons (PAHs) with a computational cost many orders of magnitude lower than what a first-principles…

Astrophysics of Galaxies · Physics 2020-10-20 Peter Kovacs , Xiaosi Zhu , Jesus Carrete , Georg K. H. Madsen , Zhao Wang

Electricity expense management presents significant challenges, as this resource is susceptible to various influencing factors. In universities, the demand for this resource is rapidly growing with institutional expansion and has a…