Search Publications
Catalog of spiral arm tangents (Galactic longitudes) in the Milky Way, and the age gradient based on various arm tracers
Vallée, Jacques P.
An updated catalog of 205 observed tangents to the spiral arms (in Galactic longitudes) since 1980 is presented. This represents an addition of 80 arm tangents in 6 years (since 2016). Most arm tangents are observed at telescopes in the radio régime.
In this study, the separation of each arm tracer from the dust lane is analysed to obtain the…First photometric and orbital period investigations of the total-eclipse contact binary V0339 Com
Yu, Yun-Xia; Hu, Ke; Xiang, Fu-Yuan +2 more
We presented the first photometric and orbital period investigation for the W UMa-type binary V0339 Com. The multi-bands light curves were obtained and analyzed with the Wilson-Devinney Code. The photometric solutions suggested that V0339 Com is an A-subtype shallow contact binary with a degree of contact f = 12 . 0% . The total eclipse of V0339 C…
Absolute parameters of four W UMa stars with extreme low mass ratios
Popov, Velimir A.; Petrov, Nikola I.
Photometric observations of four extreme low mass ratio W UMa binaries with wide total eclipses, and their absolute parameters are presented. The main results are as follows: (i) ASAS J015429+2042.8 is of A subtype while V755 Cep, VESPA V22 and GSC 02800-01387 are of W subtype; (ii) The mass ratios are close to the lower mass-ratio limit and can b…
On the Sun's distance from the center and the shape of the inner halo in the Galaxy: Gaia EDR3, HST and literature globular clusters
Gedalin, Michael; Jiang, Ing-Guey; Griv, Evgeny
A statistical method is used to derive both the Sun's distance r0 from the Galactic Center (GC) and the 3D geometry of the inner (< 25 kpc) halo. The spatial distribution of the 138 Gaia EDR3 globular clusters (GCs) with distances established on a combination of HST and literature data of Baumgardt and Vasiliev (2021) is explored. An…
Relations between global seismic parameters and activity cycles of the Sun
Chang, Heon-Young; Kim, Ki-Beom
It is suggested that the dependency of the global asteroseismic parameters on stellar properties such as magnetic activity is carefully calibrated with a homogenous data sample in stellar parameters in the sense that the empirical scaling relations of the global asteroseismic parameters are used in estimating fundamental stellar properties. As an …
Orbital period changes in IO Cep, IM Cep and TX Ari: Path to masses of distant components
Bakış, V.; Eker, Z.; Bakış, H. +7 more
Three Algol-type binary systems (IO Cep, IM Cep and TX Ari) showing cyclic orbital period changes are studied. The combination of time of minimum data from the ground-based observations together with high precision photometric data from the TESS satellite enabled us to estimate the basic light curve elements of binary systems and mass functions fo…
An astrometric and photometric study of the young open cluster NGC 2168 and its possible member [NBN2015]77
Hendy, Y. H. M.; Shokry, A.; Saad, S. M. +2 more
We present an astrometric and photometric study of the young open star cluster NGC 2168 and its proposed member [NBN2015]77. NGC 2168 was investigated by combining data from both the Gaia-ESO DR2 and the 2MASS databases. The photometric analysis and light curve modeling of the W UMa star [NBN2015] 77 in V and R bands was performed using the Wilson…
First photometric investigation of two short-period eclipsing binaries ASAS J105115-6032.1 and GDS J1056047-604149
Sarotsakulchai, Thawicharat; Soonthornthum, Boonrucksar; Liu, Nian-Ping +1 more
ASAS J105115-6032.1 (hereafter ASAS J1051) and GDS J1056047-604149 (hereafter GDS J1056) are two short-period contact binaries close to each other in the Antarctica sky area. By analyzing the light curves from AST3-1, the first photometric solutions are presented using the Wilson-Devinney (W-D) method. It is detected that both systems are W-type c…
A photometric study of V608 Cam: apparent period changes as a result of surface activity
Wolf, M.; Walter, F.; Šebek, F.
The VRI light curves were measured for the low-mass eclipsing binary V608 Cam as a part of our long-term observational project for studying of eclipsing binaries with a short orbital period. The TESS light curve solution in PHOEBE results to the detached configuration, where the temperature of the primary component was fixed to T1 = 530…
A possible large-scale alignment of galaxy spin directions - Analysis of 10 datasets from SDSS, Pan-STARRS, and HST
Shamir, Lior
Multiple observations made by several different telescopes have shown asymmetry between the number of spiral galaxies rotating in opposite directions in different parts of the sky. One of the immediate questions regarding the possible asymmetry of the spin directions is whether the distribution forms a cosmological-scale axis. This paper analyzes …