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Author: ktj

White paper on X-ray interferometry ?>

White paper on X-ray interferometry

Together with many colleagues, I have contributed to a White Paper on a possible X-ray Interferometry mission. This project is led by Phil Uttley from the University of Amsterdam, and we hope to be considered for ESA’s Vision 2050 mission slot. X-ray interferometry can yield amazing spatial resolution for bright X-ray sources, even though there is still quite some technology to be developed. For stars and exoplanets, we could spatially resolve transits in front of the stellar corona – see…

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Exostar19 research program in Santa Barbara ?>

Exostar19 research program in Santa Barbara

This summer I organized a 3-month research program called Exostar19 (https://www.kitp.ucsb.edu/activities/exostar19) at the Kavli Institute for Theoretical Physics (KITP) in Santa Barbara, together with Bekki Dawson, Dan Huber, and Jim Fuller. Victor Silva Aguirre was the one who brought us all together with his idea to come up with a program that focuses on all the new insights that the stellar and planetary field can gain from TESS and Gaia data. It’s now the last week of the program, and…

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New paper: a small planet in the temperate zone of K2-133 ?>

New paper: a small planet in the temperate zone of K2-133

A new paper by my PhD student Rob Wells is now accepted for publication: “Validation of a temperate fourth planet in the K2-133 multiplanet system“, Wells, R.; Poppenhaeger, K.; Watson, C. A. Abstract: We present follow-up observations of the K2-133 multiplanet system. Previously, we announced that K2-133 contained three super-Earths orbiting an M1.5V host star – with tentative evidence of a fourth outer-planet orbiting at the edge of the temperate zone. Here, we report on the validation of the presence…

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Review on star-planet systems ?>

Review on star-planet systems

My review talk on interactions in star-planet systems I gave at the XMM-Newton science workshop in summer 2018 is now published in a peer-reviewed article: “How stars and planets interact: A look through the high-energy window“, Poppenhaeger, Katja Abstract: The architecture of exoplanetary systems is often different from the solar system, with some exoplanets being in close orbits around their host stars and having orbital periods of only a few days. In analogy to interactions between stars in close binary…

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New papers: exoplanets and stellar results from NGTS ?>

New papers: exoplanets and stellar results from NGTS

The Next Generation Transit Survey has had some new discoveries over the past few months which I was happy to contribute to. We’ve discovered a new exoplanet (an inflated hot Jupiter), a fully-convective eclipsing binary system, and a giant flare with pulsations on a pre-main sequence M star. The papers are: “NGTS-2b: an inflated hot-Jupiter transiting a bright F-dwarf”, L. Raynard and 44 co-authors including K. Poppenhaeger, Monthly Notices of the Royal Astronomical Society, Volume 481, Issue 4, p.4960-4970 (2018)…

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Home colloquium at AIP ?>

Home colloquium at AIP

Today I gave the colloquium talk at my new home institution, the AIP. I chose a quite relatable title with “A field trip to the exoplanet zoo”, and I was blown away by how many people showed up. We actually had to open the second half of the lecture hall, which is usually only done for conferences – quite flattering! It was good fun and my colleagues from the AIP and the university had a bunch of interesting questions. Looking…

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Invited colloquium at API Amsterdam ?>

Invited colloquium at API Amsterdam

Last week I was a guest at the Anton Pannekoek Intitute at the University of Amsterdam for two days and gave an invited colloquium. Also learned a lot about the research going on at Amsterdam, especially in the exoplanet groups of Birkby and Desert. Title and abstract of my talk: Strange beasts in the exoplanet zoo Almost all exoplanets known today are orbiting around cool stars. This is caused by certain biases in our planet detection methods, but nevertheless it…

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Arrival at my new institute in Potsdam ?>

Arrival at my new institute in Potsdam

I’m a tenured full professor now! I’ve started my new position, a joint professorship at the Leibniz Institute for Astrophysics Potsdam (AIP) and the University of Potsdam, this autumn. I had a very good time in Belfast, but it’s really nice to be back in my home country and have continued access to European funding, whatever will happen with Brexit. Fortunately my two PhD students in Belfast are both in their final year now, so I can supervise them from…

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Cool Stars 20 conference in Boston ?>

Cool Stars 20 conference in Boston

This summer the Cambridge Workshop on Cool Stars, Stellar Systems and the Sun had its 20th anniversary, and took place in Boston. This is my favourite conference series, and this year I was really excited because I had the honour of being an invited speaker. I gave a talk on “How planets affect cool stars”, and had a lot of good interactions with people about the science of stars and exoplanets. This was the first time I’ve given an invited…

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New paper: X-ray emission line spectra of main-sequence stars ?>

New paper: X-ray emission line spectra of main-sequence stars

We investigated the X-ray emission line spectra of cool main-sequence stars in order to construct their emission measure distributions and compare them to the Sun: “A Chandra/LETGS Survey of Main-sequence Stars” We analyze the X-ray spectra of 19 main-sequence stars observed by Chandra using its LETGS configuration. Emission measure (EM) distributions are computed based on emission line measurements, an analysis that also yields evaluations of coronal abundances. The use of newer atomic physics data results in significant changes compared to…

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