Kinematics And Ellipsoidal Motion Of The Mid To Late M-Type Stars
| Autor: | Mohamed I. Nouh, W. H. Elsanhoury, Richard Lacy Branham, Amnah S. Al-Johani |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
Stellar kinematics Velocity dispersion Sigma FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Type (model theory) Astrophysics - Astrophysics of Galaxies Galaxy Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Vertex (curve) Astrophysics::Earth and Planetary Astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Oort constants |
| DOI: | 10.48550/arxiv.2109.11056 |
| Popis: | Truly, kinematics in the Solar neighborhood has provided important information both for the structure and for the evolution of the Galaxy since the early 20th century. The relationship between Oort constants and the ratio of the velocity dispersion are important quantities in stellar kinematics. In the present paper, we calculated the kinematical parameters and the Oort constants of various samples of late to intermediate M-type stars. We calculated the velocity dispersion ({\sigma}_1,{\sigma}_2,{\sigma}_3 ) in units of km s-1 for the samples under study. The longitude of the vertex (l_2 ) having negative values with our analysis; i.e., the program I (538 stars), l_2 =-0_.^o 5410, program II (100 stars), l_2=-0_.^o 4937 and program III (60 stars), l_2=-0_.^o 9495. We calculate the Oort constants as A=14.69+-0.61 km s-1 kpc-1 and B=-16.70+-0.67 km s-1 kpc-1, and the rotational velocity V_o=257.38+-9.40 km s^(-1). A possible explanation for the overestimated values of the second Oort constants has been presented. Comment: 17 pages, 1 figure, 4 tables |
| Databáze: | OpenAIRE |
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