Katja Poppenhaeger

This is somewhat unusual research for me, but it was good fun – some recent work about identifying an emission line in the X-ray regime which is excited by photons from a different atomic species which just happens to have the correct wavelength for that. This can be used as an independent density diagnostics for plasma in flaring loops, for example. The paper has just been published, here is the title and abstract: “X-ray line coincidence photopumping in a solar…

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The mission paper about the Next Generation Transit Survey (NGTS), a ground-based telescope network to search for transiting exoplanets, has just been published. I’m happy to be part of this project, which is a collaboration between several universities in the UK, Germany, Chile, and Switzerland – lots of exciting discoveries to come soon! Here’s some more info about the paper: We describe the Next Generation Transit Survey (NGTS), which is a ground-based project searching for transiting exoplanets orbiting bright stars….

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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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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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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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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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Happy to report that our paper has also been picked for presentation on the Astrobites blog: https://astrobites.org/2017/03/24/a-neutron-star-in-the-eye-of-sauron/. Here’s the abstract of the paper: Fomalhaut b is a directly imaged object in the debris disk of the star Fomalhaut. It has been hypothesized to be a planet, however there are issues with the observed colours of the object that do not fit planetary models. An alternative hypothesis is that the object is a neutron star in the near fore- or background…

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