Kinematics And Ellipsoidal Motion Of The Mid To Late M-Type Stars

TL;DR

This study analyzes the kinematics of mid to late M-type stars in the Solar neighborhood, calculating key parameters like Oort constants and velocity dispersions to understand stellar motion and Galactic structure.

Contribution

It provides new calculations of kinematic parameters and Oort constants specifically for late to intermediate M-type stars, expanding understanding of stellar motions in this spectral class.

Findings

Calculated velocity dispersions for M-type stars.

Derived Oort constants A and B with associated uncertainties.

Estimated the rotational velocity V_o of the Galaxy.

Abstract

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.