Zobrazeno 1 - 10
of 43
pro vyhledávání: '"D. G. Turner"'
Publikováno v:
Odessa Astronomical Publications, Vol 33, Iss 0, Pp 65-71 (2020)
Thirty three spectra of the Polaris system obtained in August–December 2019 and February–April 2020 at the 0.81m telescope of the Three College Observatory (TCO, North Carolina, USA) were used to determine the radial velocities (RV) and effective
Externí odkaz:
https://doaj.org/article/8bfbe17e56bc498f995c38a1a3b71023
Autor:
I. A. Usenko, A. Yu. Kniazev, I. Yu. Katkov, V. V. Kovtyukh, T. V. Mishenina, A. S. Miroshnichenko, D. G. Turner
Publikováno v:
Odessa Astronomical Publications, Vol 33, Iss 0, Pp 58-64 (2020)
We present the results of a spectro- scopic and photometric investigation of 18 probable members of the open cluster Collinder 220, which contains the Cepheid UW Car. Besides the Cepheid, we studied tree K-giants, two B-giants, and twelve B-A-F main
Externí odkaz:
https://doaj.org/article/5888b6cc78d340e783ed8557cb7df10b
Autor:
I. A. Usenko, A. Yu. Kniazev, I. Yu. Katkov, V. V. Kovtyukh, T. V. Mishenina, A. S. Miroshnichenko, D. G. Turner
Publikováno v:
Odessa Astronomical Publications, Vol 32, Iss 0, Pp 91-96 (2019)
We present the results of a spectro- scopic and photometric investigation of 20 objects from the open cluster Collinder 394, which contains the Cepheid BB Sgr. Besides the Cepheid, we studied tree K-giants, four B-giants, and twelve B-A-F main sequen
Externí odkaz:
https://doaj.org/article/d08d4f04680c4311815e4520e046385a
Autor:
I. A. Usenko, A. S. Miroshnichenko, S. Danford, V. V. Kovtyukh, D. G. Turner, A. V. Shulga, Yu. I. Protsyuk
Publikováno v:
Odessa Astronomical Publications, Vol 31, Iss 0, Pp 113-116 (2018)
We present the results of an analysis of the spectra of nine so called Polaris cluster A−FV stars obtained during 2016 - 2018. Radial velocities (RV) and GAIA DR 18 parallaxes-distances for these stars allow us to determine their membership in the
Externí odkaz:
https://doaj.org/article/04870a9993fd4337904261e0492ce51f
Autor:
I. A. Usenko, A. Yu. Kniazev, V. V. Kovtyukh, T. V. Mishenina, A. S. Miroshnichenko, D. G. Turner, Yu. I. Protsyuk
Publikováno v:
Odessa Astronomical Publications, Vol 31, Iss 0, Pp 117-122 (2018)
We present the results of a spectroscopic and photometric investigation of 15 objects from the open cluster NGC 5662, which contains the Cepheid V Cen. Besides the Cepheid, we studied one G-supergiant, two K-giants, four B-giants, and seven main sequ
Externí odkaz:
https://doaj.org/article/3680c17013d94076b04e810f8d364582
Autor:
D. G. Turner, L. N. Berdnikov
Publikováno v:
Odessa Astronomical Publications, Vol 14, Iss 0, Pp 170-173 (2017)
Analyses of Cepheid period changes using O-C diagrams are used to establish the direction of evolution of individual stars through the instability strip. The superposition of random in period on O-C data is less easy to interpret. Such chaotic behavi
Externí odkaz:
https://doaj.org/article/bc518ecc88044b5cb10259a83c5adfeb
Autor:
D. G. Turner
Publikováno v:
Odessa Astronomical Publications, Vol 18, Iss 0, Pp 119-122 (2017)
The type C semi-regular (SRC) variables are M-type supergiants like Betelgeuse that undergo regular periodic brightness fluctuations superposed upon seemingly irregular trends. Many of the 55 recognized Milky Way M-type supergiants belonging to the c
Externí odkaz:
https://doaj.org/article/1a5cff1f3ef748b78a2fd772f98e18e2
Autor:
D. G. Turner
Publikováno v:
Odessa Astronomical Publications, Vol 18, Iss 0, Pp 115-118 (2017)
Although Polaris is generally regarded as an overtone pulsator that may soon switch to pulsation in the fundamental mode, it is argued that the variable is actually crossing the instability strip for the first time and is in the process of leaving th
Externí odkaz:
https://doaj.org/article/406d704b8a7b406a96b1d4b425d4b419
Publikováno v:
Odessa Astronomical Publications, Vol 18, Iss 0, Pp 87-89 (2017)
The variability of the type C semi-regular (SRC) M3.5 Ia supergiant variable BC Cyg is examined with reference to measurements of its photographic B magnitude derived from 866 archival plates in the Harvard and Sternberg collections and eye estimates
Externí odkaz:
https://doaj.org/article/45635cd0e8cf46e587cd802b7643cf8a
Publikováno v:
Odessa Astronomical Publications, Vol 18, Iss 0, Pp 26-28 (2017)
The distribution of Cepheids in the Galaxy is studied using a new catalogue of Cepheid distances in conjunction with the method of hierarchical clustering. The resulting delineation of Cepheid complexes is compared with those for other Population I o
Externí odkaz:
https://doaj.org/article/a5e15c88267141dc9c303015d4952216