Search Publications
Discovering New B[e] Supergiants and Candidate Luminous Blue Variables in Nearby Galaxies
Bonanos, Alceste Z.; Maravelias, Grigoris; Tramper, Frank +3 more
Mass loss is one of the key parameters that determine stellar evolution. Despite the progress we have achieved over the last decades we still cannot match the observational derived values with theoretical predictions. Even worse, there are certain phases, such as the B[e] supergiants (B[e]SGs) and the Luminous Blue Variables (LBVs), where signific…
Complex Organics in Space: A Changing View of the Cosmos
Kwok, Sun
Planetary explorations have revealed that complex organics are widely present in the solar system. Astronomical infrared spectroscopic observations have discovered that complex organics are synthesized in large quantities in planetary nebulae and distributed throughout the galaxy. Signatures of organics have been found in distant galaxies, as earl…
Reddening-Free Q Parameters to Classify B-Type Stars with Emission Lines
Aidelman, Yael; Cidale, Lydia Sonia
The emission-line B-type stars constitute a heterogeneous group. Many of these stars show similar optical spectroscopic features and color indices, making it difficult to classify them adequately by means of photometric and spectroscopic techniques. Thus, it is relevant to deal with appropriate classification criteria to avoid as many selection ef…
Refining Orbits of Bright Binary Systems
Miroshnichenko, Anatoly S.; Danford, Stephen; Andronov, Ivan L. +3 more
We obtained spectra of several bright binary systems (ζ02 UMa, 2 Lac, and ϕ Aql), which were mostly observed with photographic plates and whose orbits were not determined very accurately. Each system was monitored for a few years with the 81-cm telescope equipped with an échelle spectrograph at the Three College Observatory in North Carolina. The …
Resonant Effects of a Bar on the Galactic Disk Kinematics Perpendicular to Its Plane
Vieira, Katherine; Carraro, Giovanni; Korchagin, Vladimir +2 more
Detailed analysis of kinematics of the Milky Way disk in the solar neighborhood based on the GAIA DR3 catalog reveals the existence of peculiarities in the stellar velocity distribution perpendicular to the galactic plane. We study the influence of resonances—the outer Lindblad resonance and the outer vertical Lindblad resonance—of a rotating bar …
Recent Progress in Finding Binary Systems with the B[e] Phenomenon
Raj, Ashish; Chojnowski, S. Drew; Manset, Nadine +9 more
This paper describes recent studies of the FS CMa-type objects, a group of stars showing the B[e] phenomenon defined in 2007. The objects exhibit strong emission-line spectra with both permitted and forbidden lines suggesting the presence of a B-type star as well as strong IR excesses due to radiation of circumstellar dust. These properties are ha…
New Method to Detect and Characterize Active Be Star Candidates in Open Clusters
Granada, Anahí; Eenmäe, Tõnis; Ghoreyshi, Maziar R. +1 more
With the aim of better understanding the physical conditions under which Be stars form and evolve, it is imperative to further investigate whether poorly studied young open clusters host Be stars. In this work, we explain how data from Gaia DR2 and DR3 can be combined to recover and characterize active Be stars in open clusters. We test our method…
A Scattered Star Group in the Orion A Region of the Milky Way
Kovaleva, Dana; Sapozhnikov, Sergei; Vereshchagin, Sergei +4 more
Using Gaia DR3 data, we identified an extended a ~60 pc group of stars sharing common motion but scattered in space, including from 150 to 300 probable members, named Group V. It can be associated with a group identified by Getman et al. (2019) and by Jerabkova et al. (2019) as a relic of a gas filament, traced by the mutual position of stars afte…
A Comprehensive Study of Soft X-ray Absorption Features in GX 13+1 Using XMM-Newton Observations
Mahato, Rabindra; Baruah, Monmoyuri
In this study, a comprehensive analysis of the reflection grating spectrometer (RGS) data (energy range 0.33 keV to 2.5 keV) of GX 13+1 from the XMM-Newton space observatory was conducted. Numerous absorption lines have been described in earlier publications, although the majority of these investigations focused on the energy range between 3 keV a…
Revealing the Binarity of HD 36030—One of the Hottest Flare Stars
Karpov, Sergey; Németh, Péter; Maryeva, Olga
The Kepler and TESS space missions significantly expanded our knowledge of what types of stars display flaring activity by recording a vast amount of super-flares from solar-like stars, as well as detecting flares from hotter stars of A-F spectral types. Currently, we know that flaring occurs in the stars as hot as B-type ones. However, the struct…