Lund Observatory

department of Astronomy and Theoretical Physics

Seminars at Lund Observatory

Astronomy seminars are given in English. They are open to all, but aimed at an audience with basic knowledge in astrophysics. Unless otherwise noted, seminars take place on Thursdays 14:15 in Lundmarksalen.

Spring 2018


PhD seminars

2018-01-25 Mirek Giersz
Black holes in stellar clusters
2018-02-01 Jayne Birkby
New frontiers in exoplanet characterisation
Exoplanet characterization is undergoing a rapid evolution, especially in the study of exoplanet atmospheres. I will discuss the very latest results from both space and ground-based observations and highlight how they are helping us to understand exoplanet origins and diversity. I will focus part of my talk on high-resolution spectroscopy, which is a robust and powerful tool in exoplanet characterization. It uses changes in the Doppler shift of a planet to disentangle its spectrum from the glare of its host star. The technique is sensitive to the depth, shape, and position of a planet’s spectral lines, and thus reveals information about the planet’s composition, atmospheric structure, mass, global wind patterns, and rotation. I will present MEASURE: the MMT Exoplanet Atmosphere SURvEy. This 40 night survey is the largest high-resolution study of exoplanet atmospheres to date. It contains spectra of exoplanets from hot Jupiters to warm Neptunes, both transiting and non-transiting, observing both their dayside and nightside thermal emission. I will describe the survey and present some of its exciting preliminary results. The survey not only enables a homogenous dataset to perform comparative exoplanetology, but provides complementary high-resolution spectra for exoplanets observed with HST and Spitzer. The combination of high- and low-resolution spectroscopy can provide stringent constraints on planet metallicity and C/O ratios, and signifies the next step in the detailed characterization of exoplanet atmospheres.

The Dynamical Universe for ALL

2018-02-08 Beibei Liu
Understanding the formation and evolution of super-Earth planets
Disk migration theory predicts that super-Earth planets would end up at resonance. However, the Kepler mission has found that the period ratios of these planets do not show strong pile-ups near mean motion resonances (MMRs). Here I explain a mechanism, magnetospheric rebound that can rearrange the orbits of the resonant planets during the disk dispersal phase. We conduct N-body simulations of two-planet systems and investigate under which conditions planets can escape resonances. Meanwhile, I will present a possible scenario for the formation of TRAPPIST-1. The system contains a 0.08 solar-mass star and 7 Earth planets within 0.1AU. In our scenario, planetesimal is formed at the snow line by streaming instabilities. Further mass growth is lead by efficient accretion of mm to cm-size pebbles that drifted from the outer disk. In this way, the disk solid mass is able to efficiently transferred into the planet masses.
2018-02-15 Ariel Goobar
Cosmic transparency and the dimming of standard candles
Accurate accounting for the dimming of light along the line of sight for distant sources is of great importance in astronomy. Furthermore, it is an essential step in the measurements of cosmological distances used to probe the cosmic composition. In spite of the great success in the last two decades in the use of Type Ia supernovae to measure the properties of the accelerating universe, understanding the wavelength dependence of the extinction in the supernova host galaxies has remained elusive. I will explain why this has been a puzzle and present a possible solution. A measurement of the transparency of the intergalactic medium will be discussed
2018-02-22 Marie Martig
Liverpool John Moores University
The structure of galactic thick disks
ATP talk
Wed. 15:15
Johanna Larsson
How does the culture of physics affect physics teacher education?

COMPUTE Winter meeting

2018-03-08 Fabio Antonini
University of Surrey
Nuclear clusters and (supermassive) black holes
ATP talk
Wed. 15:15
Johan Thoren
Colors in QCD
2018-03-15 Hiranya Peiris
Towards fundamental physics from cosmological surveys
Wed. 14:15
Gillian Nave
Spectra of Th/Ar and U/Ne hollow cathode lamps for spectrograph calibration
PhD defence, 09:00
Asli Pehlivan Rhodin
Experimental and computational atomic spectroscopy for astrophysics
COMPUTE seminar Mon. 14:15
Martin Turbet
Exploring the diversity of planetary atmospheres with Global Climate Models
More than 50 years ago, scientists created the first Global Climate Models (GCMs) to study the atmosphere of the Earth. Since then, the complexity and the level of realism of these models (that can now include the effect of oceans, clouds, aerosols, chemistry, vegetation, etc.) have considerably increased. The large success of these models have recently motivated the development of an entire family of GCMs designed to study extra-terrestrial environments in our solar system (Venus, Mars, Titan, Pluto) and even beyond (extrasolar planets).
I will first show various GCM applications on Venus, Mars, Titan and Pluto. Solar system GCMs successes and sometimes failures teach us useful lessons to investigate and possibly predict the possible climates on planets where no (or almost no) observations are available. I will then present several examples of studies recently performed using a 'generic' Global Climate Model developed at the Laboratoire de Météorologie Dynamique in Paris, designed to explore the possible atmospheres and the habitability of ancient planets or extrasolar planets.
Wed. 14:15
Ivan Minchev
AIP, Potsdam
Semi-empirical estimation of stellar birth radii and the time evolution of the Milky way ISM abundance gradients
Licenciate defence, Thursday 10:00
Iryna Kushniruk
Searching for kinematic structures in the Solar neighbourhood
ATP talk
Wed. 15:15
Pedro Capelo
Black hole growth in galactic nuclei

Bayes Day meeting

Lennart Lindegren
Gaia DR2
COMPUTE seminar Tue. 14:15
Alice Quillen
ATP talk
Wed. 15:15
Najmeh Abiri

Kallen symposium: Exoplanets towards the future

Master seminar
Mon. 09:15
Erik Dahlof
Master seminar
Mon. 11:15
Linn Eriksson
Master seminar
Mon. 14:15
Maria Lomaeva
Master seminar
Tue. 13:15
Sofia Savvidou
Master seminar
Tue. 15:15
Eric Andersson
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