Impact of Distance Determinations on Galactic Structure. I. Young and Intermediate-Age Tracers

• Published in: Space science reviews Vol. 214; no. 4; pp. 1 - 36
• Main Authors: Matsunaga, Noriyuki, Bono, Giuseppe, Chen, Xiaodian, de Grijs, Richard, Inno, Laura, Nishiyama, Shogo
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.06.2018; Springer Nature B.V
• Subjects: Aerospace Technology and Astronautics; Astronomical Distance Determination in the Space Age; Astronomy; Astrophysics and Astroparticles; Binary stars; Cepheid variables; Galactic disk; Galactic evolution; Galactic structure; Galaxies; Indicators; Interstellar extinction; Measurement methods; Metallicity; Open clusters; Physics; Physics and Astronomy; Planetology; Solar neighborhood; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Star & galaxy formation; Stellar evolution; Tracers; Stars: variables; Cepheids: distance scale
• ISSN: 0038-6308; 1572-9672
• DOI: 10.1007/s11214-018-0506-5

Here we discuss impacts of distance determinations on the Galactic disk traced by relatively young objects. The Galactic disk, ∼ 40 kpc in diameter, is a cross-road of studies on the methods of measuring distances, interstellar extinction, evolution of galaxies, and other subjects of interest in astronomy. A proper treatment of interstellar extinction is, for example, crucial for estimating distances to stars in the disk outside the small range of the solar neighborhood. We’ll review the current status of relevant studies and discuss some new approaches to the extinction law. When the extinction law is reasonably constrained, distance indicators found in today and future surveys are telling us stellar distribution and more throughout the Galactic disk. Among several useful distance indicators, the focus of this review is Cepheids and open clusters (especially contact binaries in clusters). These tracers are particularly useful for addressing the metallicity gradient of the Galactic disk, an important feature for which comparison between observations and theoretical models can reveal the evolution of the disk.