We present high-angular resolution observations, conducted with the Atacama Large Millimeter/Submillimeter Array (ALMA) in Band 6, of high-excitation molecular lines of ${\mathrm{CH}}_3\mathrm{CN}$, CH₃OH, and the H29$\alpha$ radio recombination line, towards the G333.6-0.2 ultracompact (UC) H ii region. Our observations reveal three hot molecular cores: A, B, and C, where emission is detected in ten components of the $J=14\to 13$ rotational ladder of ${\mathrm{CH}}_3\mathrm{CN}$ and in the CH₃OH $J=5_{1,4}\to 4_{1,3}$ transition. Rotational diagram analysis of ${\mathrm{CH}}_3\mathrm{CN}$ reveals excitation temperatures ranging from 380 to 430 K. First-order moment maps of ${\mathrm{CH}}_3\mathrm{CN}$ and CH₃OH reveal distinct velocity gradients in all cores, suggesting rotating structures, with core A also showing evidence of expansion motions. The H29$\alpha$ recombination line shows a linewidth of $30.2\pm 0.12$ km s⁻¹, dominated by dynamical and thermal broadening, indicative of large-scale motions in ionized gas. Analysis of the ionized gas properties yields an electron density of $(4.8\pm 0.4)\times {10}^5$ cm⁻³, an emission measure of $(1.23\pm 0.06)\times {10}^9$ pc cm⁻⁶, and a Lyman continuum photon flux consistent with an O5–O6 V (Zero-Age Main Sequence; ZAMS) star. Our results suggest that G333.6-0.2 is in an intermediate evolutionary stage between hypercompact (HC) and ultracompact (UC) H ii regions, hosting active high-mass star formation with rotating hot cores and ionized gas dynamics.

In recent years, the researchof bubbles,partially circular structures in the interstellar medium, consisting of dust and gas, has received the considerable attention. The analysis of the structure and evolution of bubbles provides insight into the conditions under which stars and planets form inthe interstellar medium. Dust bubbles are inextricably linked with star formation regions and are powerful tools for studying the interaction of young stellar objects with their environment at various stages of evolution.The main goal of this articleisto study the region of the N126 dust bubble, search for and identify young stellar objects. Identification of young stellar objects by their fluxes at infrared wavelengths is relatively recent, and identification criteria are still at the stage of improvement. Therefore, in this article, the criteria for identifying young stellar objects were used according to the works of Koenig X.P. (2012), Koenig X.P. & Leisawitz D.V. (2014) and Fischer W.J. (2016), which are based on analysis of WISE observational datain the near-and mid-infrared bands W1 (3.4 μm), W2 (4.6 μm), W3 (12 μm), and W4 (22 μm). The datafrom the 2MASS and AllWISE catalogswith reliable non-zero fluxes of infrared radiation sourceswere used in that work. For the researched dust bubble, young stellar objects of class 0 (protostars) and class I were not detected. 4 objects of class II, 1 object of the class of transition disks and 48 objects of class III were identified. Energy distributions in the spectra for class II objectswere constructed, which also confirmed their evolutionary status. For all identified YSOs, color diagrams were constructed showing the locations of the found objects with their corresponding areas of evolution. Maps of the distribution of YSOs in space are analyzed, which indicate possible signs of an initiated star formation process in the N126 dust bubble.

HII regions are ionized regions of interstellar gas, which ionized by intensive ultraviolet radiation from nearby hot stars. Radio recombination line is one of the main tools for investigating the HII region, in particular, the distribution of HII is obtained and the main physical conditions of the interstellar matter are determined from hydrogen lines. This study was carried out based on the analysis of the H110a recombination emission line toward the W40 HII region, which is one of the most active star-forming regions in the Aquila Molecular Cloud. We used archival observational data of the H110a radio recombination line in the Aquila Molecular Cloud, obtained during February in 2015 using the 26m NanShan radiotelescope in the Xinjiang Astronomical Observatory of the Chinese Academy of Sciences. During the period of the study, an integrated intensity map of H110a toward the W40 HII region and the corresponding spectra were constructed. The electron density and temperature of the HII region, the emission measure, the optical thickness, the Lyman continuum flux, the excitation parameter, the radius of the Strömgren sphere, and the mass of ionized hydrogen inside the sphere were calculated. The values of the emission measure and optical thickness indicate that the H110a recombination radio line is optically thin and traces a very dense region (<6462 AU) with a high electron temperature. The numbers of photons of the Lyman continuum indicates the presence of a massive O9.5 star, that equivalent to a zero-age main-sequence star located within the HII region. The obtained values of the physical parameters indicate that the region of ionized hydrogen under study is an ultracompact region. The results of this article lay the foundation for further research aimed at studying the evolution of HII regions, as well as their role in the processes of starformation. Области HII - это ионизированные области межзвездного газа, которые были ионизированы интенсивным ультрафиолетовым излучением близлежащих горячих звезд. Для изучения области НІІ одним из основных инструментов являются радиорекомбинационные линии, в частности по линиям водорода получают распределение НІІ и определяют основные физические условия межзвездной среды. Данное исследование проведено на основе анализа рекомбинационной линии излучения H110a в направлении региона W40 НІІ, который является одним из самых активных областей звездообразования в молекулярном облаке Aquila. Для проведения данного исследования нами были использованы архивные данные наблюдений радиорекомбинационной линии Н110a в молекулярном облаке Aquila, полученные в течение февраля 2015 года на 26-м радиотелескопе Нань-Шань Синьцзянской астрономической обсерватории Китайской академии наук. В ходе исследования построена карта интегральной интенсивности излучения H110a в направлении области W40 НІІ и соответствующие спектры. В исследовании были определены электронная плотность и температура региона НІІ, мера эмиссии, оптическая толщина, поток лаймановского континуума, параметр возбуждения, радиус сферы Стремгрена и масса ионизированного водорода внутри сферы. Значения меры эмиссии и оптической толщины указывают на то, что рекомбинационная радиолиния H110a оптически тонкая и прослеживает очень плотную область (<6462 а.е.) с высокой электронной температурой. Число фотонов континуума Лаймана показывает наличие массивной звезды типа О9.5, эквивалентной звезде главной последовательности нулевого возраста, расположенной внутри области HII. Полученные значения физических параметров указывают на то, что исследуемая область ионизированного водорода является ультракомпактной областью. Результаты проведенного исследования закладывают основу для дальнейших исследований, направленных на изучение природы и эволюции областей HII, а также их роли в более широком контексте в процессах звездообразования. HII аймақтары – жақын маңдағы ыстық жұлдыздардың қарқынды ультракүлгін сәулеленуімен иондалған жұлдызаралық газдың иондалған аймақтары. HII аймағын зерттеу үшін радиорекомбинациялық сызықтар негізгі құралдардың бірі болып табылады, атап...

We present high–angular resolution 1.3 mm continuum and molecular line observations toward the highmass star-forming region G350.29+0.12, using CH₃CN and CH₃¹³CN rotational transitions. The continuum emission resolves two main cores: a bright, compact northern core G350.29+0.12 A and a weaker southern core G350.29+0.12 B. Core A exhibits six compact substructures embedded within more extended emission. M K-components of the CH3CN J = 14→13 and CH3 13CN J = 14→13 transitions are detected, with the emission arising primarily from core A. The CH3CN moment 0 maps show that the integrated intensities peak at the main continuum position, indicating that the molecular emission traces warm and dense gas. The moment 1 maps reveal a pronounced velocity gradient of ∼2 km s-1 across core A, oriented from northwest to southeast, while the moment 2 maps show K-dependent variations in velocity dispersion. Position–velocity diagrams further indicate organized rotational motions, exhibiting a compact velocity structure with a central peak and systematic gradients. Rotational temperature analysis yields = 360.6 ± 34.8 K for CH3CN, tracing the hottest and densest gas and Trot = 138 ± 45 K for CH3 13CN, consistent with cooler and more extended material. Together, these results demonstrate that G350.29+0.12 A is a rotating hot molecular core undergoing active high-mass star formation.

The study of the mechanisms of star formation and evolution is based on comprehensive research into interstellar regions, including the analysis and identification of young stellar objects (YSOs). The identification of young stellar objects by their radiation at various wavelengths in the infrared range is a relatively recent development - the first studies in this field appeared only at the end of the 20th century. The development of this field has been made possible by improvements in observation techniques and data processing methods, the acquisition of more reliable characteristics of stellar sources, and the creation of catalogs containing extensive arrays of information about cosmic objects. In this study, the star-forming region W40 of the Aquilla molecular cloud was investigated in the infrared wavelength range to detect previously unidentified young stellar objects at various stages of evolution. Identification was carried out using two approaches: photometric criteria and spectral indices. This made it possible to more reliably identify the evolutionary stages of 37 newly discovered and previously unexplored YSO candidates (5 objects of class I, 2 objects of class II, 4 objects – class “transitional disks” and 26 objects — class III), which indicates an active and ongoing process of star formation in W40.

This study presents results of high-resolution spectroscopic observations of the star MWC 645, a representative of the poorly studied FS CMa-type objects. These stars are characterized by strong emission lines and significant infrared excess caused by circumstellar dust. For the first time, a cool secondary component has been detected in this system. Fundamental parameters were determined for both components: for the hot (B-type) star, an effective temperature of 18,000 ± 2000 K and luminosity log(L/L☉ ) = 3.9 ± 0.4; and for the cool (K-type) star, Teff = 4250 ± 250 K and log(L/L☉ ) = 3.1 ± 0.4. The system is located at a distance of 6.5 ± 0.9 kpc and shows clear signs of active interaction, including ongoing mass transfer indicated by the complex profiles of many emission lines. The results confirm the binary nature of MWC 645 and its classification as an FS CMa-type object. This work highlights the need for further observations to refine the system’s parameters and improve our understanding of the structure and origin of its circumstellar environment.