Event Page

Gravity or turbulence? Gaia observations through Orion

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Event Details


November 30, 2021 | Virtual seminar.

Meeting ID: 878 5755 5123
Passcode: 54548

Speaker


El Dr. Javier Ballesteros Paredes nació en la Ciudad de México, D.F., en 1966. Hizo sus estudios de maestría y doctorado en Ciencias (Astronomía) en el Instituto de Astronomía de la UNAM, realizan-do una estancia predoctoral en el Harvard-Smithsonian Center for Astrophysics en 1998, y obtenien-do la medalla Alfonso caso de la UNAM a la mejor tesis doctoral en Astronomía, en 1999. Fue uno de los primeros posdoctorantes del entonces recién inaugurado Departamento de Astrofísica del Museo Americano de Historia Natural, en Nueva York, entre 1999 y 2001. A finales de 2001, regresó a la UNAM como Investigador, trabajando para lo que ahora es el Instituto de Radioastronomía y As-trofísica de la UNAM, campus Morelia. En 2009 obtuvo el Premio Estatal de Divulgación Científica, otorgado por el Consejo Estatal de Ciencia y Tecnología de Michoacán.

About the activity


Two models of molecular cloud dynamics are in the literature. On one hand, the “turbulent” one, where MCs are supported by turbulence over several free-fall times. On the other hand, the “hierarchical and chaotic global collapse” one, which states that as MCs form, they collapse, form stars and disperse, all within a few free-fall times. In this one, the non-thermal motions that people interpret as turbulence are generated by the collapse itself, but they are hardly a mechanism that supports clouds.


Both models of MCs reproduce important observational features of MCs. Using Gaia EDR3, we have found what appears to be a distinctive feature that may allow us to disentangle which model of cloud formation and evolution is at play in MCs: the velocity dispersion of the newborn stars as a function of the mass of the stars. While turbulence models show that massive stars rapidly acquire high velocity dispersion, collap-sing models show the distinctive signs of violent relaxation, where the velocity dispersion does not depend on the mass bin of the stars.