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CCD UBV photometric and Gaia astrometric study of eight open clusters—ASCC 115, Collinder 421, NGC 6793, NGC 7031, NGC 7039, NGC 7086, Roslund 1 and Stock 21
Paunzen, E.; Güver, T.; Bilir, S. +8 more
In this study, we carried out CCD UBV photometry of eight open clusters, ASCC 115, Collinder 421, NGC 6793, NGC 7031, NGC 7039, NGC 7086, Roslund 1, Stock 21, and determined their reddening, metallicity, distance, age, and mass functions. We used new Gaia Data Release 2 (DR2) astrometric data to separate cluster member stars from the field stars a…
A young multipolar planetary nebula in the making—IRAS 21282+5050
Zhang, Yong; Kwok, Sun; Hsia, Chih-Hao +1 more
We present high-angular-resolution Hubble Space Telescope (HST) optical and near-infrared imaging of the compact planetary nebula (PN) IRAS 21282+5050. Optical images of this object reveal several complex morphological structures including three pairs of bipolar lobes and an elliptical shell lying close to the plane of the sky. From near-infrared …
Metallicity and absolute magnitude calibrations for F-G type main-sequence stars in the Gaia era
Bilir, S.; Ak, T.; Yontan, T. +3 more
In this study, photometric metallicity and absolute magnitude calibrations were derived using F-G spectral type main-sequence stars in the Solar neighbourhood with precise spectroscopic, photometric and Gaia astrometric data for UBV photometry. The sample consists of 504 main-sequence stars covering the temperature, surface gravity and colour inde…
A catalogue of 108 extended planetary nebulae observed by GALEX
Pradhan, Ananta C.; Panda, Swayamtrupta; Ojha, Devendra K. +2 more
We present the ultraviolet (UV) imaging observation of planetary nebulae (PNe) using archival data of Galaxy Evolution Explorer (GALEX). We found 358 PNe detected by GALEX in near-UV (NUV). We have compiled a catalogue of 108 extended PNe with sizes greater than
Study of eclipsing binary and multiple systems in OB associations V: MQ Cen in Crux OB1
Bakış, Volkan; Bilir, Selçuk; Nitschelm, Christian +6 more
The early-type massive binary MQ Cen (
AU Pegasi revisited: period evolution and orbital elements of a peculiar Type II Cepheid
Szabados, László; Csörnyei, Géza
New analysis on the period changes of Type II Cepheid AU Peg is presented. The available recent photometric measurements were collected and analysed with various methods. The period has been found to be constant for certain time intervals, although increasing in overall, in contrast with the previous expectations, which suggested the period change…
Gould Belt members in X-ray RAVE: cross-matching RAVE stars with 3XMM point sources
Özkan, M. T.; Plevne, O.; Coşkunoğlu, B.
In this paper the results of matching the RAdial Velocity Experiment (RAVE), a spectroscopic Southern hemisphere survey (
The puzzling high velocity G5 supergiant star HD 179821: new insight from Gaia DR2 data
Jasniewicz, G.; Parthasarathy, M.; Thěvenin, F.
HD 179821 is classified as G5 Ia star. From the IRAS colors and spectral energy distributions it was classified as a post-AGB star. But some studies classify it as a massive (30 to
Search for variable stars in the northern sky: analysis of photometric time series for 3598 stars
Tautvaišienė, G.; Drazdauskas, A.; Mikolaitis, Š. +6 more
As extensive ground-based observations and characterisation of different variable stars are of the utmost importance in preparing optimal input catalogues for space missions, our aim was to search for new variable stars in selected fields of the northern sky. We obtained 24 470 CCD images and analysed photometric time series of stars using the DAO…
The intermediate age population of the Galactic halo
Mould, Jeremy
We have learned recently that the inner halo of the Milky Way contains a kinematically coherent component (Gaia-Enceladus) from a significant merger 10 Gyrs ago. By contrast the inner (defined to exclude the Magellanic Stream) halo contains no similar intruder stellar population of billion year age. The tracer we use to set the corresponding upper…