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Celebration barbecue ?>

Celebration barbecue

This week we had a really nice afternoon barbecue with a bunch of people I like to call “star-planet group and friends” – i.e. my own group plus other colleagues mainly from the solar group and the MHD group. We had a lot to celebrate: my postdoc Ekaterina Ilin will start a new postdoctoral position in Groningen very soon, where she will work with Harish Vedantham on radio signatures of star-planet interactions; Prachi Rahate and Joana Wokittel have successfully defended…

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Paper on tidally-induced activity in an M dwarf / brown dwarf pair ?>

Paper on tidally-induced activity in an M dwarf / brown dwarf pair

My PhD student Nikoleta Ilic has investigated a really interesting object, the close M dwarf / brown dwarf pair NLTT 41135, which forms a hierarchical wide triple system with the M dwarf NLTT 41136. Nikoleta found an elevated activity of about an order of magnitude in X-rays that is most likely caused by tidal interaction between the brown dwarf and the M dwarf. Nikoleta was able to quantify this with the help of other wide M dwarf systems from the…

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EAS conference in Krakow ?>

EAS conference in Krakow

A good chunk of my research group plus myself spent last week in Krakow/Poland at the annual meeting of the European Astronomical Society (EAS). First time for me: we all took a “Eurocity” train that goes directly from Berlin to Krakow and takes 7 hours. Ecofriendly, and I was actually less wrung out after the train trip than I would have been after two flights (since there are no direct plane connections between Berlin and Krakow). The conference itself was…

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XMM-Newton Large Program: magnetism of old suns ?>

XMM-Newton Large Program: magnetism of old suns

I’m very excited these days because the first observation from my recently awarded XMM-Newton large observing program keeps getting scheduled and then re-scheduled by the XMM team. If all goes well, the first data will be collected before the end of June. The observing program is about the magnetism of old sun-like stars; specifically, my co-investigators and I want to figure out if there is still a magnetic braking mechanism operating in old stars that are rotating anomalously quickly. The…

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Paper on host star activity and the exoplanet radius gap ?>

Paper on host star activity and the exoplanet radius gap

Laura Ketzer, one of my PhD students, recently published a detailed study on the fate of small exoplanets – super-Earths and mini-Neptunes – under different time evolutions of the magnetic activity of the host star. The so-called radius gap manisfests itself differently for stars that experience an early versus a late spin-down. Also in samples of mixed stellar spin-down histories the features of the gap as a whole change with age, so that uniform age samples, such as open stellar…

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Paper on tidal star-planet interactions ?>

Paper on tidal star-planet interactions

My PhD student Nikoleta Ilic has published a project we have been working on for the past two years: the identification of tidal star-planet interaction in a sample of planet-hosting stars. The tidal interaction leads to a spin-up of the host stars, which we identified through comparisons with co-eval companion stars in wide orbits around the star-planet systems. The paper was also featured in a joint press release of the AIP and the Harvard-Smithsonian Center for Astrophysics: https://chandra.harvard.edu/press/22_releases/press_110222.html Ilic, N….

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Instrumentation projects presented at SPIE ?>

Instrumentation projects presented at SPIE

My group is involved in two instrumentation projects that presented updates at the recent SPIE conference: the ANDES spectrograph for the ELT, where we at the AIP are responsible for the design and the construction of its UBV arm; and ARCUS, a concept for a high spectral resolution X-ray space telescope, where I am involved in the exoplanet science goals. The SPIE proceedings for both projects can be found here: Marconi et al., “ANDES, the high resolution spectrograph for the…

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Completed PhD theses ?>

Completed PhD theses

Two PhD students successfully defended their PhD theses after the summer break: Dr. Grace Foster completed her thesis and defense on “X-ray studies of exoplanet systems” in August 2022; Dr. Ekaterina Ilin completed her thesis and defense on “High lights: stellar flares as probes of magnetism in stars and star-planet systems” in September 2022.   Congratulations! Grace has started a job as a data scientist in the US, and Ekaterina will begin a postdoc position in my group on her…

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Cool Stars 21 conference in Toulouse ?>

Cool Stars 21 conference in Toulouse

This year the Cool Stars conference – the most important conference for the stellar half of my group’s research – took place in person again, for the first time since the pandemic started. Toulouse hosted the meeting this year, and it was a really good conference, lots of new scientific insights. A pretty big delegation from my group attended: PhD students Laura Ketzer, Ekaterina Ilin, Nikoleta Ilic, Judy Chebly, and guest student Yu Xu; postdocs Eliana Amazo-Gomez and Juli├ín Alvarado-Gomez;…

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PETS paper II: Thermal Inversion Agents in KELT-20 b/MASCARA-2 b ?>

PETS paper II: Thermal Inversion Agents in KELT-20 b/MASCARA-2 b

The second paper of the PEPSI Exoplanet Transit Survey (PETS) performs a search for possible atomic and molecular species that may drive the thermal inversion in the atmospheres of ultrahot Jupiters, and it rules out several species in the case of KELT-20 b/MASCARA-2 b: Title: “The PEPSI-LBT Exoplanet Transit Survey (PETS). II. A Deep Search for Thermal Inversion Agents in KELT-20 b/MASCARA-2 b with Emission and Transmission Spectroscopy” Johnson, Marshall C.; Wang, Ji; Pai Asnodkar, Anusha; Bonomo, Aldo S.; Gaudi,…

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