Search Publications
The Effect of the LMC on the Milky Way System
Vasiliev, Eugene
We review the recent theoretical and observational developments concerning the interaction of the Large Magellanic Cloud (LMC) with the Milky Way and its neighbourhood. An emerging picture is that the LMC is a fairly massive companion (10–20% of the Milky Way mass) and just passed the pericentre of its orbit, likely for the first time. The gravita…
Vertical Structure of the Milky Way Disk with Gaia DR3
Vieira, Katherine; Carraro, Giovanni; Korchagin, Vladimir +1 more
Using a complete sample of about 330,000 dwarf stars, well measured by Gaia DR3, limited to the galactic north and south solid angles |b|<75° and up to a vertical distance of 2 kpc, we analyze the vertical structure of the Milky Way stellar disks, based on projected tangential velocities. From selected subsamples dominated by their correspondin…
The Influence of the Galactic Bar on the Dynamics of Globular Clusters
Carraro, Giovanni; Korchagin, Vladimir; Tkachenko, Roman +2 more
We make use of recent estimates for the parameters of the Milky Way's halo globular clusters and study the influence of the galactic bar on the dynamics of these clusters by computing their orbits. We use both an axisymmetric and non-axisymmetric galactic potentials, which include the rotating elongated bar/bulge structure. We account for observat…
Dense Molecular Environments of B[e] Supergiants and Yellow Hypergiants
Kraus, Michaela; Torres, Andrea F.; Kourniotis, Michalis +2 more
Massive stars expel large amounts of mass during their late evolutionary phases. We aim to unveil the physical conditions within the warm molecular environments of B[e] supergiants (B[e]SGs) and yellow hypergiants (YHGs), which are known to be embedded in circumstellar shells and disks. We present K-band spectra of two B[e]SGs from the Large Magel…
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…
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…