The giant molecular cloud Orion A is the closest massive star-forming region to earth (d ∼ 400 pc). It contains the rich Orion Nebula Cluster (ONC) in the North, and low-mass star-forming regions (L1641, L1647) to the South. To get a better understanding of the differences in star formation activity, we perform an analysis of the gas mass distribution and star formation rate across the cloud. We find that the gas is roughly uniformly distributed, while, oddly, the ONC region produced about a factor of ten more stars compared to the rest of the cloud. For a better interpretation of this phenomenon, we use Gaia DR2 parallaxes, to analyse distances of young stellar objects, using them as proxy for cloud distances. We find that the ONC region indeed lies at about 400 pc while the low-mass star-forming parts are inclined about 70∘ from the plane of the sky reaching until ∼470 pc. With this we estimate that Orion A is an about 90 pc long filamentary cloud (about twice as long as previously assumed), with its “Head” (the ONC region) being “bent” and oriented towards the galactic mid-plane. This striking new view allows us to perform a more robust analysis of this important star-forming region in the future.

Thousands of planets outside the Solar system have been discovered, with exoplanets in different environments. Since we cannot expect to find an exoplanetary system fully resembling our Solar System, we consider a Solar System type configuration where the Earth moves in an eccentric orbit. We focus on young Earth 1 billion years ago, when the Sun’s extreme UV (EUV) flux was about 5 times higher than the current radiation. In case of eccentric motion of Earth, strong variations of the EUV flux would influence the evolution of the planet’s atmosphere (EUV radiation of 50 times the current EUV flux would be possible). Taking into account a certain amount of Nitrogen in the atmosphere of such a young Earth, we study the non-thermal loss of N2 over a long time interval. We therefore investigate to what extent eccentric motion will influence the conditions of habitability of a terrestrial planet.

We propose induction heating of planetary interiors as an energy source in the planetary mantles. Induction heating arises when a changing magnetic field induces currents in a conducting planetary mantle which then dissipate to heat the planet, mostly within an upper layer called the skin depth. This physical process can play a role in planetary interiors around strongly magnetized stars such as low mass M dwarfs with kG magnetic fields, which are common among these stars.

We report on the detection of a rich water reservoir in the protostellar envelope of the Class 0 source HH211. In striking contrast to all other molecules detected with Herschel/PACS, water emission peaks around the central source where both ortho and para forms are detected. The measured ortho-to-para ratio of just 0.65 indicates formation of water-ice at very low temperatures and a non-destructive photo-desorption process around the protostar. While part of the H2O emission is likely related to collisional excitation, the centralized morphology around the protostar suggests that radiative excitation is also significant, despite the fact that radiation appears to have a very different impact on the H2O molecules when compared to the terminal outflow shocks. The very low ortho-to-para ratio suggests that H2O around the protostar originates from primordial envelope material that has never been thermally processed before.

The present-day Earth with its innumerable life forms is a product of cosmic evolution starting with the formation of our galaxy and the dense gas clouds within it, and proceeding through the contraction of one of those clouds about 4.6 Gyr ago, first into filaments and then one or more protostellar disks, planets, and central stars, one of which was our Sun. Radioactive debris from a massive nearby star was included. The planets themselves formed through coagulation, accretion, and fragmentation of solid bodies. Habitability depends on a delicate balance between disk accretion by gravity and dispersal by the central star, which determine the size of the planet and its gaseous envelope, combined with a long period of stellar radiation, which has to disperse this envelope but leave a hospitable secondary atmosphere. The final step toward life involves even more complexity as self-replicating bio-molecules form with ever increasing stability.