SPECTROSCOPIC INVESTIGATIONS OF GALACTIC CLUSTERS WITH ASSOCIATED CEPHEID VARIABLES. I. POLARIS CLUSTER AND α UMI

Автор(и)

  • I. A. Usenko Astronomical Observatory, Odessa National University, Mykolaiv Astronomical Observatory, Ukraine
  • A. S. Miroshnichenko Dept. of Physics and Astronomy, University of North Carolina at Greensboro, United States
  • S. Danford Dept. of Physics and Astronomy, University of North Carolina at Greensbo, United States
  • V. V. Kovtyukh Astronomical Observatory, Odessa National University, Ukraine
  • D. G. Turner Dept. of Physics and Astronomy, Saint Mary’s University, Canada
  • A. V. Shulga Mykolaiv Astronomical Observatory, Ukraine
  • Yu. I. Protsyuk Mykolaiv Astronomical Observatory, Ukraine

DOI:

https://doi.org/10.18524/1810-4215.2018.31.145379

Ключові слова:

Open clusters, Stars, radial velocities, GAIA parallaxes, Cepheids, main-sequence stars, effective temperatures, distances, α UMi

Анотація

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 cluster and to construct its 3D kinematic model. However Teff for four stars determined spectroscopically give cause
for doubts about the GAIA DR 18 parallaxes accuracy. The comparison between their MV and distances with the those from Pecaut & Mamajek (2013) calibrations shows significant differences for the objects with parallaxes less than 8 mas. The differences in distances
increase exponentially with decreasing parallax. These facts indicate an unreliability of the GAIA DR2 parallx measurements of less than 10 mas. We estimated the distance to Polaris B to be 104.2 pc. 

Посилання

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Опубліковано

2018-10-23

Номер

Том 31 (2018)

Розділ

Астрофізика (зоряні атмосфери, взаємодіючі подвійні системи, змінні зорі)

Ліцензія

Авторське право (c) 2018 Odessa Astronomical Publications

Creative Commons License

Ця робота ліцензується відповідно до Creative Commons Attribution-NonCommercial 4.0 International License.

Відповідно Закону України про авторське право і суміжні права N 3792-XII від 23 грудня 1993 року