Search Publications
Strong Variability in AzV 493, an Extreme Oe-type Star in the SMC
Oey, M. S.; Renzo, M.; Castro, N. +11 more
We present 18 yr of OGLE photometry together with spectra obtained over 12 yr revealing that the early Oe star AzV 493 shows strong photometric (ΔI < 1.2 mag) and spectroscopic variability with a dominant, 14.6 yr pattern and ~40 day oscillations. We estimate the stellar parameters T eff = 42,000 K, $\mathrm{log}L/{L}_{\odot }=5.83\p…
Gamma rays from nebulae around recurrent novae
Bednarek, W.; Sitarek, J.
Novae were discovered to emit transient γ rays during the period of several days to a few weeks after initial explosion, indicating presence of acceleration processes of particles in their expanding shells. In the case of recurrent novae, electrons can be in principle accelerated in the nova shells for the whole recurrence period of nova producing…
HD 32239: An Algol type eclipsing binary with a γ Doradus type component
Gürol, Birol
HD 32239 is an Algol-type eclipsing binary with one of the components showing γ Doradus type pulsation. In this study by using the Transiting Exoplanet Survey Satellite (TESS) observations of the HD 32239 system published in Sectors 5 and 32, we obtained the minima times of the eclipsing system and calculated the new light elements by using the (O…
A Search for X-Ray/UV Correlation in the Reflection-dominated Seyfert 1 Galaxy Markarian 1044
Jithesh, V.; Medhi, Biman J.; Misra, Ranjeev +3 more
Correlated variability between coronal X-rays and disk optical/UV photons provides a very useful diagnostic of the interplay between the different regions around an active galactic nucleus (AGN) and how they interact. AGNs that reveal strong X-ray reflection in their spectra should normally exhibit optical/UV to X-ray correlation consistent with r…
Orbit determination for the binary Cepheid V1344 Aql
Szabados, L.; Cseh, B.; Kovács, J. +4 more
Context. Binary Cepheids play an important role in the investigation of the calibration of the classical Cepheid period-luminosity relationship. Therefore, a thorough study of individual Cepheids belonging to binary systems is necessary.
Aims: Our aim is to determine the orbit of the binary system V1344 Aql using newly observed and earlier pu…
Star Structure of the Northern Part of the Orion Sword Region
Vereshchagin, S. V.; Chupina, N. V.
According to the data of the Gaia DR3 catalogs, the belonging of the stars of group 189 ([1]), located in the northern part of the Orion Sword region, to the open star cluster (OSC) NGC 1977 was analyzed. To do this, the revision of the stellar composition of the northern part of the Orion Sword region (around the center of the OSC NGC 1977) was c…
Atmospheric Pressure and Molecular Cloud Formation in Early-type Galaxies
McNamara, B. R.; Russell, H. R.; Edge, A. C. +3 more
A strong correlation between atmospheric pressure and molecular gas mass is found in central cluster galaxies and early-type galaxies. This trend and a similar trend with atmospheric gas density would naturally arise if the molecular clouds condensed from hot atmospheres. Limits on the ratio of molecular to atomic hydrogen in these systems exceed …
Deep and shallow crustal structure control on the late-stage volcanism in Syria Planum (Mars)
Pozzobon, Riccardo; Mazzarini, Francesco; Isola, Ilaria
Long-lasting widespread volcanism in Mars is testified by the Tharsis volcanic province, one of the largest volcanic provinces with the largest shield volcanoes of the Solar System. However, volcanism on Mars is characterized also by the occurrence of broad volcanic fields, either in the form of small lava shields or monogenic volcanic cones. The …
WISE Green Objects (WGOs): The Massive Star Candidates in the Whole Galactic Plane (∣b∣ < 2°)
Yuan, Jing-Hua; Zhang, Guo-Yin; Zhang, Chang +1 more
Massive young stellar objects (MYSOs) play a crucial role in star formation. Given that MYSOs were previously identified based on the extended structure and the observational data for them is limited, screening the Wide-field Infrared Survey Explorer (WISE) objects showing green features (for the common coding of the 4.6 µm band as the green…
Transverse Vertical Oscillations During the Contraction and Expansion of Coronal Loops
Li, Qiao; Zhang, Qingmin; Li, Chuan +5 more
In this paper, we carry out a detailed analysis of the M1.6 class eruptive flare occurring in NOAA active region 13078 on 2022 August 19. The flare is associated with a fast coronal mass ejection (CME) propagating in the southwest direction with an apparent speed of ~926 km s-1. Meanwhile, a shock wave is driven by the CME at the flank.…