Instituto de Física y Astronomía

y Centro de Astrofísica de Valparaíso

Tandem Group SymposiumSelection Symposium for the leader of the Valparaíso-Max Planck Tandem group on Planet and Star Formation

July 18, 2016, Sala Juan Mouat, Facultad de Ciencias, Universidad de Valparaíso, Chile - 8.30 -15.40 hrs

This Symposium for the selection of the person who will lead the Valparaíso-Max Planck Tandem Group on Planet and Star Formation will be held on July 18, from 8.30 to 15.40 hrs at the Sala Juan Mouat in the Facultad de Ciencias, Gran Bretaña 1111, Playa Ancha, Valparaíso. Each candidate will give a seminar which will be open to all interested.


8.30 - 9.10 hrs

Diego Muñoz, Cornell University, USA
Title: "The Role of Stellar Binaries in the Formation and Dynamics of Planets"

Abstract: Almost 50% of main sequence stars are members of binary stellar systems. From a dynamical standpoint, stellar companions are known to alter planetary orbits and planet-forming disks in diverse ways. Despite these (presumably) hazardous environments, planets have been detected both inside and around binaries, suggesting that the mere presence of a companion does not catastrophically arrest a remarkably robust planet-formation process. Although this suggests binarity is not a fundamental obstacle to forming planets, there is observational evidence indicating that planet formation may proceed qualitatively differently when subject to stellar multiplicity. For example, infrared excesses and sub-mmm fluxes (tracers of disk mass) decrease with binary separation. Likewise, planet bearing frenquencies are smaller in the presence close companions. At the same time, stars that are hosts to hot Jupiters have a higher companion fraction than their field analogs. Consequently, binaries do play a role in the formation and evolution of planets. In this talk, I will discuss diverse aspects of planet formation and dynamics *inside and around* stellar binaries. Using theoretical and direct-simulation tools, I will describe binary-related processes that take place during the protoplanetary disk phase, during the main sequence phase, and during the post-main sequence phase. In some of these cases, direct gas-dynamical simulations are instrumental in understanding the coupling between stars and gas disks, such as the case of a young binary accreting from a circumbinary disk. Circumbinary disks may provide not only clues on planet formation, but also on star formation, as they are found around the close stellar pairs for which there is no comprehensive formation theory. I will also present calculations of N-body and secular dynamics, with applications to the origin of hot Jupiters and ultra-short period planets inside binaries. Finally, I will discuss the role that binaries might have in the pollution of white-dwarfs after old planetary systems have been disintegrated during the post-main sequence phase of stellar evolution.

9.10 - 9.50 hrs

Johan Olofsson, Universidad Valparaiso, Chile, Valparaiso

Title: "From dust to planets: debris disks evolution"

Abstract: Circumstellar disks are the birthplaces of giant and terrestrial planets, and their respective evolution are intimately connected. With thousands of exoplanets discovered, it seems clear that planetary formation is an efficient process. And yet, from an observational point of view, we barely scratched the surface of how planets form. A promising strategy to address such a challenging question is to study the disks at key stages of their evolution, when planet formation is thought to happen. The motivation of my research is to constrain how circumstellar disks evolve within the first 100 Myr, and thus better understand the conditions in which planets can form. In this talk, I will first present the global picture that I constructed over the years, highlighting the observational and modeling expertises that I developed. I will then present the ambitious research project that I propose to lead as the Max Planck Tandem Group Leader in Valparaiso. This project aims at connecting disk and planet studies, with a clear emphasis on addressing the outcomes of giant planetary formation and possibly on-going terrestrial planet formation in young (10-100Myr) debris disks.

9.50 - 10.30 hrs

Dmitry Semenov, Max-Planck Institut for Astronomy, Heidelberg, Germany

Title: "Molecular Astrophysics of Protoplanetary Disks and Formation of Planets"

Abstract: Fascinating discoveries of diverse exoplanetary systems call for a better understanding of planet formation process, which begins in planetary nurseries — protoplanetary disks. Protoplanetary disks are compact, ~100-1000 AU objects that contain ~0.01 M_Sun mass of gas and dust left after the formation of a central star. The new observational facilities such as Atacama Large Millimeter Array, NOEMA interferometer, SPHERE/VLT, and forthcoming James Webb Space Telescope yield the sensitivity and resolving power required to study in detail physics and chemistry in many disks.  It is challenging though to extract a wealth of information from these rich data mainly due to complexity of data analysis and modeling. Thermal dust continuum data provide information on the disk dust masses and temperatures, but are hard to interpret without proper knowledge of the dust size distribution and opacities. Molecular line spectra provide information on gas temperature, densities, kinematics, ionization state, etc. Yet the analysis of these line date requires understanding of the line excitation, which involves coherent modeling of the disk physical structure, chemistry, and line radiative transfer.  In my presentation I'll show how one could use high-resolution observations and modeling of protoplanetary disks to address some of the fundamental questions
related to the planet formation:

- Which processes shape the disk structure and regulate their evolution?
- How turbulent are the disks?
- What are the chemical complexity prior and at the verge of planet formation?
- Are there abundant organic compounds that may facilitate the origin of life?

As concluding remarks, I'll present my future research plans for this exciting topic.

13.30 - 14.30 hrs   Lunch Break

14.30 - 15.10 hrs

Koraljka Muzic, Universidad Diego Portales, Santiago, Chile

Title: "Young brown dwarfs: Exploring the Substellar IMF across the environments"

Abstract: Bridging the realms of stars and planets, brown dwarfs represent important  benchmarks for testing formation theories of both classes of objects. In  particular, studies of substellar objects at young ages are crucial for  understanding the mass dependence in the formation and early evolution of  stars. Thanks to an extensive observational effort over the last decade,  including our deep survey SONYC (Substellar Objects in Nearby Star  Clusters), we now know that every star forming region within 500 parsecs harbours a substantial population of substellar objects, with the mass  function extending down to at least 5-10 MJup. Thus, the processes of star  and planet formation overlap in the brown dwarf regime, forming a continuum   of stellar, substellar and planetary masses.  While we can confidently say that the brown dwarf frequencies and the  shape of the IMF are now well constrained down to masses around, and   even below deuterium-burning limit in low-density star forming regions,  several important questions remain. Can density and presence of  massive stars affect the shape of the low-mass portion of the IMF, and  in which way? There are observational hints, as well as theoretical predictions  that this might be so. What is the mass of the least massive brown dwarf  free-floating in clusters? Do these planetary-mass objects form in a process  that is similar to forming stars, or planets? All these questions are directly related to the quest of understanding which is the dominant process responsible  for the formation of brown dwarfs.  In this talk I will present our current understanding of young substellar  populations, highlighting the results of our deep imaging and spectroscopic  survey SONYC. I will also present two recently initiated observational studies,  along with an outlook for the future, designed to tackle the outstanding  questions featured above.

15.10 - 15.40 hrs

Sebastian Perez, Universidad de Chile, Santiago, Chile

Title: "Observing on-going planet formation through a synergy between 3D modelling and observations"

Abstract: As rapid progress is being made on the observational and theoretical forefronts of planet research, synergetic efforts between theory and observation become essential. A continuous discovery of extrasolar planets, accompanied by breakthrough observations of circumstellar disks —the birthplaces of planets—, currently excite a whirlwind of observational questions and concurrent theoretical ideas. In this talk, I will describe the current picture of planet formation and the interplay between theory and observations. I will present observational diagnostics, inspired from hydrodynamic calculations, with which we will be able to confirm protoplanets detected with high-contrast AO imaging and determine their masses using dynamical arguments. These masses are crucial to constrain planet formation theories. I will describe new avenues of observational work aimed at directly witnessing different stages of protoplanetary architecture, such as observing protolunar disks, and I will comment on the importance of binarity and stellar interactions in disk evolution and planet formation, particularly in the context of ALMA and extreme AO instrumentation. Finally, I will discuss funding strategies to develop high power computing in the tamdem group at U. de Valparaiso, which will further potentiate interactions with local groups. I will also propose a new avenue within the current trend of policies for Chilean resources for science, technology and innovation driven by developing a strong connection with the educational sector.










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