Recent Talks

Among the over 450 known exoplanets, the planets that transit their central star stand out, due to the wealth of information that can be gained about both planet and central star. The CoRoT mission has been designed to detect smaller and longer-periodic transiting exoplanets than can be found from ground observations. CoRoT-9b was detected by the satellite in summer 2008 and underwent follow-up observations from ground for another year. It stands out as having the largest periastron distance of all transiting planets, being expected to maintain permanently a moderate surface temperature, estimated between 250 and 430K. It is also the first exoplanet to which planet evolution models can be applied, without uncertain corrections that have been needed for 'hot' transiting planets. These models indicate it to be rather similar to Jupiter. Temperate gas-giant planets with low-to-moderate eccentric orbits constitute the largest group of currently known planets; they are probably similar to the gas giants of the solar system. With CoRoT-9b being this group’s first transiting planet, it may give rise to a much better understanding of these common planets. While CoRoT-9b itself is certainly not habitable, moons around it could be similar to Titan and provide some chance of habitability. Upcoming observations with the Spitzer space telescope are designed to improve on planet parameters and to perform a deeper search for the detection of its moons.

The quiet Sun (the 99%, or more, of the solar surface not covered by sunspots or active regions) is receiving increased attention in recent years; its role on the global magnetism and its complexity are being increasingly recognised. A picture of a rather stochastic quiet Sun magnetism is emerging. From these recent works, the quiet Sun magnetism is presented as a myriad of magnetic field vectors having an isotropical distribution with a cascade of scales down to the mean free path of the photon. But this chaotic representation also shows clear signs of intermittency: at a low frequency rate (0.022 events h^-1 arcsec^-2) the magnetic field appear in the quiet Sun forming well-organised loop structures at granular scales. More interesting, these loops rise to higher layers and their energy input into the chromosphere can be important for the heating of this layer. In the talk, I will present a pedagogic view of the quiet Sun magnetism. I will focus on the ascent of the smallest ever observed magnetic flux emergence through the solar atmosphere. More specifically, I will show how to infer from high resolution, spectro-polarimetric observations (taken with the SOT instrument onboard Hinode) the magnetic topology of the fields, how they rise through the photosphere to the chromosphere, and the implications of this phenomena for chromospheric (and coronal) heating.

An analysis of the impact of seismic and volcanic activity was carried out at selected astronomical sites, namely the observatories of El Teide (Tenerife, Canary Islands), Roque de los Muchachos (La Palma, Canary Islands), Mauna Kea (Hawaii) and Paranal (Chile) and the candidate site of Cerro Ventarrones/Armazones (Chile). In this sense, we studied the impact of seismicity, volcanic ash clouds, lava flows and ground deformation. Hazard associated with volcanic activity is low or negligible at all sites, whereas seismic hazard is very high in Chile and Hawaii. The lowest geological hazard in both seismic and volcanic activity was found at Roque de los Muchachos observatory, in the island of La Palma.

It has been recently shown that the chemical composition of the Sun is anomalous when compared to most nearby stars of very similar fundamental parameters, so-called solar twins. Compared to these stars, the Sun is deficient in refractory elements relative to volatiles, a finding that we speculate is a signature of the terrestrial planet formation that occurred around the Sun but not in the majority of solar twins. I will discuss these and newer related results, the strengths and weaknesses of our planet formation interpretation, as well as our plans for future observations that can help us better understand the nature of the abundance trends found.

Nature is one of the world's leading scientific journals, publishing many papers that receive wide attention by the general public. But, Nature is very selective —> < 7% of submitted papers are published. In order to maximize your chances of getting published, papers should present fundamental new physical insights, or startling observations/results. Theory papers pose additional problems, as we want only those papers that are likely to be the correct explanation, and not simply exploring parameter space. The writing should be clear, concise and directed at the level of a graduate course in the subject. I encourage authors to contact me in advance of submission of a paper, both to ascertain the appropriateness of the result for Nature, and to ensure that the writing is close to our standards. Posting to ArXiv is and always has been allowed, but authors should discuss the specifics with their institutional public affairs officers before doing so. Lapses in professional ethics seem to be on the rise? I will discuss some examples, and what we should be doing to keep astronomy clean.