Zobrazeno 1 - 10
of 37
pro vyhledávání: '"Berdnikov, Leonid N."'
Autor:
Yacob, Alemiye M., Berdnikov, Leonid N., Pastukhova, Elena N., Kniazev, Alexei Y., Whitelock, Patricia A.
In this study, we investigate the period changes of eight short-period Type II Cepheids of the BL Her subtype, i.e., with periods in the 1-4 day range. The $O-C$ diagrams for these stars are constructed using all suitable observational data from grou
Externí odkaz:
http://arxiv.org/abs/2207.14695
The mass-luminosity relation is a fundamental law of astrophysics. We have suggested that the currently used mass-luminosity relation is not correct for the M/M_sun > 2.7 range of mass since it was created using double-lined eclipsing binaries, where
Externí odkaz:
http://arxiv.org/abs/2004.04115
Autor:
Rastorguev, Alexey S., Lazovik, Yaroslav A., Zabolotskikh, Marina V., Berdnikov, Leonid N., Gorynya, Natalia A.
A new version of the Baade--Becker--Wesselink (hereafter BBW) method is proposed, based on direct spectroscopic measurements of effective temperatures of 45 northern Cepheids, made in different pulsating phases. By comparing the temperature estimates
Externí odkaz:
http://arxiv.org/abs/1911.10413
Autor:
Rastorguev, Alexey S., Dambis, Andrey K., Zabolotskikh, Marina V., Berdnikov, Leonid N., Gorynya, Natalia A.
The BBW method remains one of most demanded tool to derive full set of Cepheid astrophysical parameters. Surface brightness version of the BBW technique was preferentially used during last decades to calculate Cepheid radii and to improve PLC relatio
Externí odkaz:
http://arxiv.org/abs/1212.3173
Autor:
Majaess, Daniel J., Turner, David G., Gieren, Wolfgang P., Berdnikov, Leonid N., Lane, David J.
Classical Cepheids remain a cornerstone of the cosmic distance scale, and thus characterizing the dependence of their light amplitude on metallicity is important. Period-amplitude diagrams constructed for longer-period classical Cepheids in IC 1613,
Externí odkaz:
http://arxiv.org/abs/1211.4026
Autor:
Majaess, Daniel J., Turner, David G., Gallo, Luigi C., Gieren, Wolfgang P., Bonatto, Charles, Balam, David D., Lane, David J., Berdnikov, Leonid N.
New X-ray (XMM-Newton) and JHKs (OMM) observations for members of the star cluster Alessi 95, which Turner et al.(2012) discovered hosts the classical Cepheid SU Cas, were used in tandem with UCAC3 (proper motion) and 2MASS observations to determine
Externí odkaz:
http://arxiv.org/abs/1205.0016
Space reddenings are derived for 15 Galactic Cepheids from dereddening CCD BVRIc data for AF-type stars in the immediate vicinities of the variables, in conjunction with 2MASS reddenings for BAF-type stars in the same fields. Potential reddening solu
Externí odkaz:
http://arxiv.org/abs/1107.1258
Random changes in pulsation period occur in cool pulsating Mira variables, Type A, B, and C semiregular variables, RV Tauri variables, and in most classical Cepheids. The physical processes responsible for such fluctuations are uncertain, but presuma
Externí odkaz:
http://arxiv.org/abs/1102.4338
Autor:
Turner, David G., Majaess, Daniel J., Lane, David J., Szabados, L., Kovtyukh, V. V., Usenko, I. A., Berdnikov, Leonid N.
A selection of known and newly-discovered northern hemisphere Cepheids and related objects are being monitored regularly through CCD observations at the automated Abbey Ridge Observatory, near Halifax, and photoelectric photometry from the Saint Mary
Externí odkaz:
http://arxiv.org/abs/0907.2969
Autor:
Turner, David G., Percy, J. R., Colivas, T., Berdnikov, Leonid N., Abdel-Latif, Mohamed Abdel-Sabour
Random changes in pulsation period are well established in cool pulsating stars, in particular the red giant variables: Miras, semi-regulars of types A and B, and RV Tau variables. Such effects are also observed in a handful of Cepheids, the SX Phe v
Externí odkaz:
http://arxiv.org/abs/0907.2818