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Long-term, orbital, and rapid variations of the Be star V923 Aql = HD 183656
Wolf, M.; Harmanec, P.; Bakış, V. +9 more
We present the latest results of a long-term observational project aimed at observing, collecting from the literature, and homogenising the light, colour, and spectral variations of the well-known emission-line Be star V923 Aql. Our analysis of these parameters confirms that all of the observables exhibit cyclic changes with variable cycle length …
The dust-star interplay in late-type galaxies at z < 0.5: Forecasts for the JWST
Baes, Maarten; Bendo, George J.; Fritz, Jacopo +4 more
Context. In recent years, significant growth in the amount of data available to astronomers has opened up the possibility for extensive multi-wavelength approaches. In the field of galaxy evolution, such approaches have uncovered fundamental correlations, linking the dust component of a galaxy to its star formation rate (SFR). Despite these achiev…
V355 And: a neglected detached binary in a multiple star system
Özkardeş, B.
The analysis of light curves (from TESS, ASAS--SN and KWS databases) of the eclipsing binary V355 And is presented for the first time. The O-C diagram was constructed using all available times of minimum light together with the ones determined in this study, and the revised ephemeris was obtained. The final photometric model describes V355 And as …
Electron Bulk Heating at Saturn's Magnetopause
Masters, A.; Kane, M.; Achilleos, N. +3 more
Magnetic reconnection at the magnetopause (MP) energizes ambient plasma via the release of magnetic energy and produces an "open" magnetosphere allowing solar wind particles to directly enter the system. At Saturn, the nature of MP reconnection remains unclear. The current study examines electron bulk heating at MP crossings, in order to probe the…
The First Light Curve Solution of GW Leo and Refined Ephemeris of Two Contact Binary Systems
Poro, A.; Davoudi, F.; Lashgari, E. +6 more
We performed the first light curve analysis of GW Leo and a new ephemeris is obtained for QT Boo. The light curve investigation also yields that the system GW Leo is a contact W UMa eclipsing binary with a photometric mass ratio of q = 0.44 ± 0.03, a fillout factor of f = 59.6%, and an inclination of 50.77° ± 0.09°. Due to the O'Connell effect whi…
Far-UV Fe emission as proxy of Eddington ratios
Zheng, Wei
The Eddington ratio is a key parameter that governs the diversity of quasar properties. It can be scaled with a strong anticorrelation between optical Fe IIopt and [O III] emission. In search of such indicators in the far-UV band, the Hubble Space Telescope far-UV spectra of 150 low-redshift quasars are analysed in combination with thei…
The Vertical Extent of Enhanced Densities in Cusp Like Regions of the Ionosphere of Mars
Kopf, A. J.; Withers, P.; Golden-Marx, E.
Unusually large values of peak electron density in the ionosphere of Mars are occasionally observed in cusp like regions of crustal magnetic field. These features are observed as atypical examples of oblique echoes in ionograms. However, the vertical extent over which electron density values are enhanced has not yet been determined. Furthermore, t…
X-ray observations of two candidate symbiotic binaries in the galactic bulge
Maccarone, T. J.; Britt, Christopher T.; Torres, M. A. P. +6 more
This paper analyses X-ray observations by the Chandra X-ray Observatory of CXOGBS J174614.3-321949 (CXB3) and CXOGBS J173620.2-293338 (CX332), two symbiotic binary star candidates identified by the Galactic Bulge Survey. Using new Chandra observations, we improved their X-ray positional uncertainties to 0.24 and 0.92 arcsec, respectively, confiden…
Discovery of Romanov V20, an Algol-Type Eclipsing Binary in the Constellation Centaurus, by Means of Data Mining
Romanov, Filipp Dmitrievich
I report my discovery of the large-amplitude Algol-type eclipsing binary system which was initially added to the AAVSO International Variable Star Index (VSX) under the designation of Romanov V20. I describe selection criteria for searching for variability among other stars, the search of photometric data from several sky surveys, and my observati…
Irregular emission cycles in the Oe star HD 60 848
Nazé, Yaël; Fló, Joan Guarro; Rauw, Gregor +2 more
We analyse the spectroscopic and photometric variability of the Oe star HD 60 848 over the last twenty five years. The spectra reveal recurrent, but irregular cycles of increased circumstellar emission lines. These cycles are highly asymmetric displaying a slow increase over about 6 years, followed by a fast decay within about 6 months. Our analys…