All future seminars

Nombre d'entrades: 2

25
Maig 2018

Radial velocities of cool stars with rocky planets


Inici: 12:15h
Ponent: Manuel Perger (Institut de Ciencies de l'Espai (CSIC-IEEC))
Lloc: Sala Alberto Lobo (ICE building, Campus UAB)

We are already able to detect potentially habitable, rocky planets with the precision of modern Doppler spectroscopy. At least if they orbit a low-mass star. In this domain however, magnetic phenomena of the host star affect the measurements and are even able to hide and mimic a true planetary signal.…
Inici: 12:15h
Ponent: Manuel Perger (Institut de Ciencies de l'Espai (CSIC-IEEC))
Lloc: Sala Alberto Lobo (ICE building, Campus UAB)

We are already able to detect potentially habitable, rocky planets with the precision of modern Doppler spectroscopy. At least if they orbit a low-mass star. In this domain however, magnetic phenomena of the host star affect the measurements and are even able to hide and mimic a true planetary signal. A challenge in modern radial velocity planet searches is therefore the understanding of the different stellar contributions. In this talk I will explain how we measure and obtain high-precision radial velocities and how we can disentangle the different contributions. With this focus, I will discuss in length the recent findings of exoplanets like Proxima Centauri b, GJ 3998b,c, GJ 3942b, and will give previews on my recent research target. 
29
Maig 2018

Reading between the lines: Adventures in spectroscopy of young and wild stars and their environments


Inici: 12:00h
Ponent: Aurora Sicilia-Aguilar (SUPA, School of Science and Engineering, University of Dundee (UK))
Lloc: Sala Alberto Lobo (ICE building, Campus UAB)

Emission lines are one of the defining characteristics of young stars, and carry an overwhelming (and not-so-easy-to-extract) amount ofinformation about accretion and activity processes in the stellar magnetosphere and innermost disk. Using time-resolved spectroscopy covering several rotational and…
Inici: 12:00h
Ponent: Aurora Sicilia-Aguilar (SUPA, School of Science and Engineering, University of Dundee (UK))
Lloc: Sala Alberto Lobo (ICE building, Campus UAB)

Emission lines are one of the defining characteristics of young stars, and carry an overwhelming (and not-so-easy-to-extract) amount ofinformation about accretion and activity processes in the stellar magnetosphere and innermost disk. Using time-resolved spectroscopy covering several rotational and disk orbital periods, we can obtain a very detailed view of the structure and variability of accretion columns and spots and information on the presence and launching points of stellar/disk winds in young stars. Time-resolved emission (and absorption) line spectroscopy can also trace parts of the inner disk at
scales that are not accessible by direct imaging or interferometry. Understanding these processes and how they affect the observed spectra can also help us to identify (or rule out) the presence of young and newly-formed planets and stellar companions that may be perturbing the disk.

I will present the results for four stars with very different spectral types and behaviours (EX Lupi, GW Ori, ASASSN-13db, and ZCMa), discussing the power and limitations of emission line tomography and exploring what we can learn from "reading between the (spectral) lines" in these and other objects.

Finally, I will also discuss how we can apply similar analysis techniques to other types of sources and to the analysis of molecular line profiles in star-forming regions, to explore and visualize the velocity structure and the formation history of the cluster.
 
Institute of Space Sciences (IEEC-CSIC)

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08193 Barcelona.
Phone: +34 93 737 9788
Email: ice@ice.csic.es
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An institute of the Consejo Superior de Investigaciones Científicas

An institute of the Consejo Superior de Investigaciones Científicas
Affiliated with the Institut d'Estudis Espacials de Catalunya

Affiliated with the Institut d'Estudis Espacials de Catalunya