S345: Origins: From the Protosun to the First Steps of Life

Planetary orbits

Schematic drawings of planetary orbits around stars of different masses and temperatures, each with four planets of fixed orbital radii with shifting habitable zones (green). The stars heat the planets differently, with the high-mass, high-luminosity, high-temperature stars heating the planets the most (bluer colours) and the low-mass, low-luminosity, low-temperature stars heating the planets the least (redder colours). (NASA / Kepler Mission / Dana Berry)

IAU Symposium 345, Origins: From the Protosun to the First Steps of Life, highlights new research on the formation of Sun-like stars and protoplanetary disks, the origin of the short-lived radioisotopes in meteorites, the formation and observation of Earth-like planets, early conditions on Earth and early life.

These were the essential steps toward life on Earth. Research in this field has progressed rapidly in recent years. Observations provide a growing consensus for how the Sun and its planets formed and for how Earth formed within the Solar System. The formation of early life is difficult to trace, but we are close to understanding the conditions for habitability, how these conditions arose and the nature of the first organisms. While walking along this path, Symposium 345 will trace our origin in the Universe. The implications of these discussions will bridge our knowledge to disciplines far beyond astrophysics.

The Symposium will run Monday through Thursday of the first week of the General Assembly with 10 sessions and more than 100 posters. Each session will start with an invited review followed by four contributed talks. Manuel Güdel (University of Vienna) will give a summary plenary talk on Wednesday, 22 August.

Monday will focus on star formation and the chain of events that may have been involved in the formation of Earth and the earliest life forms, some of which have been inferred by detailed observations and computer models. The morning sessions will focus on star formation in the stellar neighbourhood, starting with Mika Juvela from the University of Helsinki and Christoph Federrath from Australian National University. The afternoon sessions will cover star formation in dense interstellar clouds with a review by Christoph Federrath of the Australian National University in Canberra.

Near-infrared image of the PDS 70 disk obtained with the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) at the Very Large Telescope of the European Southern Observatory in Chile. Emissions from the central star are masked, revealing a young exoplanet as a bright dot.
Credit: (ESO / A. Müller, MPIA)

The environment of the early Sun will be reviewed Tuesday morning by Edward Young from the University of California, Los Angeles, including the possible effects of young stellar clustering and peculiarities in the isotopic composition of meteorites. Protoplanetary disks that may form Earth-size planets will be covered on Tuesday afternoon by Laura Perez of the Universidad de Chile, Santiago. Such disks have been studied at high resolution using interferometric techniques at infrared and radio wavelengths.

The physical and chemical properties of protoplanetary discs will be reviewed Wednesday morning by Inga Kamp, from the Kapteyn Astronomical Institute, including evidence for Earth-size planets around other stars and clues to the formation process of Earth itself. Afternoon sessions on the processes involved with the formation of terrestrial planets will be reviewed by Eiichiro Kokubo of the National Astronomical Observatory of Japan.

The origin of the Earth’s water, crust and atmosphere will be discussed on Thursday morning by Doris Breuer of the German Aerospace Centre (DLR), Institute of Planetary Research, Berlin, followed by a review of the early evolution of the terrestrial planets in our Solar System by Helmut Lammer from the Austrian Academy of Science in Graz. The afternoon sessions will start with a review of the properties of Earth-like planets by Daniel Apai of the University of Arizona. The final steps to life, from non-living to living, will be addressed by Addy Pross of Ben Gurion University of the Negev in the last session on Thursday.

BRUCE ELMEGREEN is President of Division H. He does research on stellar and star-cluster formation and galactic structure and is a staff member of the IBM Research Division in Yorktown Heights, New York.

L. VIKTOR TÓTH is a member of the Division H Steering Committee. He studies the cold interstellar medium and star formation at the Eötvös Loránd University and at the Konkoly Observatory Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, in Budapest.

MANUEL GÜDEL focuses his research on star formation, protoplanetary disks and stellar jets, stellar magnetic activity and exoplanetary habitability. He is at the Department of Astrophysics of the University of Vienna.