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Author: ktj

New paper: Discovery of three (plus one) small planets around a small star ?>

New paper: Discovery of three (plus one) small planets around a small star

Happy to report that we have discovered three small planets, plus one additional candidate planet, around a small cool star. This is some very nice work by my PhD student Rob Wells. The planets were discovered using data from the Kepler K2 space telescope. The planets are in fairly close orbits around their host star; the candidate planet, for which we need some more data to be certain it is really a planet, might be in the habitable zone of…

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Conference: “Ages^2 – Taking stellar ages to the next power” ?>

Conference: “Ages^2 – Taking stellar ages to the next power”

I spent some time at a fantastic conference, “Ages^2 – Taking stellar ages to the next power” on Elba, Italy. It was a great meeting, with people from very different areas of astronomy coming together to share progress on measuring how old different kinds of stars are, which is a very fundamental and very difficult to solve question. I gave an invited talk on the topic of “Precise stellar ages as the key to exoplanet evolution”, and my PhD student…

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Press release: Are we being watched? Tens of other worlds could spot the Solar System ?>

Press release: Are we being watched? Tens of other worlds could spot the Solar System

This is a week full of press releases: my other PhD student, Rob Wells, just published a paper in MNRAS about transit zones (places in the sky where an extraterrestrial observer could detect our solar system planets through transits). There are about 70 currently known exoplanet systems that are located in the solar system’s transit zones. None of those have any known habitable zone planets, but prospects of finding a habitable system with mutual transit visibility are good: the Kepler-K2…

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Press release: X-rays Reveal Temperament of Possible Planet-Hosting Stars ?>

Press release: X-rays Reveal Temperament of Possible Planet-Hosting Stars

My PhD student Rachel Booth has been working on X-ray data from several space telescopes and has published our findings in MNRAS recently: X-ray emission from stars quiets down with age much more dramatically than thought before (see here for more details about the paper). Now NASA has published a press release on Rachel’s research, here is the link: https://www.nasa.gov/mission_pages/chandra/news/x-rays-reveal-temperament-of-possible-planet-hosting-stars.html. Some really nice results, and hopefully we’ll be able to collect more data soon and study this in even more…

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New paper: Transit visibility zones of the solar system planets ?>

New paper: Transit visibility zones of the solar system planets

New paper by my PhD student Rob Wells: The detection of thousands of extrasolar planets by the transit method naturally raises the question of whether potential extrasolar observers could detect the transits of the Solar System planets. We present a comprehensive analysis of the regions in the sky from where transit events of the Solar System planets can be detected. We specify how many different Solar System planets can be observed from any given point in the sky, and find…

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Arcus, a new high-resolution X-ray spectrometer in space ?>

Arcus, a new high-resolution X-ray spectrometer in space

Very good news: the Arcus mission – a high-resolution X-ray spectrograph onboard a small space telescope – has received funding from NASA for a concept study! I am part of the proposal team as an international collaborator, our PI is Randall Smith from the Harvard-Smithsonian Center for Astrophysics. We just received 2 million US$ funding through NASA’s MIDEX mission call for phase A, and we will be working frantically on Arcus for the next year to demonstrate it can actually…

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New paper: Next Generation Transit Survey (1) ?>

New paper: Next Generation Transit Survey (1)

I’m happy to be part of the Next Generation Transit Survey (NGTS) collaboration, a ground-based array of telescopes in Chile searching for exoplanets transiting their host stars. We have just published a paper on detecting false positives with NGTS, namely background transits of dim stars across brighter stars, through centroid vetting. The paper is accepted for publication by Monthly Notices of the Royal Astronomical Society. “Centroid vetting of transiting planet candidates from the Next Generation Transit Survey”, accepted by MNRAS…

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Musings on teaching ?>

Musings on teaching

I will teach some new lecture courses this fall, and therefore I think a short review of my teaching over the past two years is in order. I’ve taught the module “Computational modelling in physics” twice in a row now, it’s a lecture and computer lab course for the first-year physics students. For some students, it’s the first time they actually program something, while others already have quite some experience when they start university. I introduced the students to Python…

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New paper: Magnetic activity of old cool stars ?>

New paper: Magnetic activity of old cool stars

Happy to report that my PhD student Rachel Booth has successfully published her first paper! It’s a very interesting analysis of the magnetic activity of old cool stars, with a surprising find about the decline of activity at old stellar ages. Our paper has also been featured on the Astrobites blog: https://astrobites.org/2017/07/03/adventures-in-watchmaking-for-cool-stars/. Here’s the abstract of the paper: Stars with convective envelopes display magnetic activity, which decreases over time due to the magnetic braking of the star. This age-dependence of…

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Conference “Atmospheres of disks and planets” at castle Ringberg ?>

Conference “Atmospheres of disks and planets” at castle Ringberg

I just spent a really exciting week at castle Ringberg in south Germany, where the Max-Planck Institute for Astronomy held a conference on exoplanet formation and atmospheric composition. Lots of interesting discussions and new results. I was invited to give a talk on the topic of “Stellar activity and planet characterisation” – one of my favourite topics to talk about. My personal highlight of the conference was Yamila Miguel’s presentation about the latest results from the Juno mission: we finally…

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