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Category: research

Paper on helium transits of exoplanets ?>

Paper on helium transits of exoplanets

During the first Covid lockdown I started what I call my little pandemic project. But then all the real-life consequences of living through a worldwide pandemic set in, and it took until early this year to wrap up my project. It is finally done! And it is the first single-author paper I have ever written. Here’s some information on the paper: Helium absorption in exoplanet atmospheres is connected to stellar coronal abundances Poppenhaeger, K. Transit observations in the helium triplet…

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Code published: AltaiPony ?>

Code published: AltaiPony

My PhD student Ekaterina Ilin investigates stellar flares in various space-based observations, and has developed a flare-finding code names AltaiPony already a while ago. We used this in several of her papers, for example for the flare census in open clusters (Ilin et al. 2019, Ilin et al. 2021) and the high latitude flares on M dwarfs (Ilin et al. 2021, blog post). After having it available on github already for a good while, Ekaterina has now also published her…

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New group members and completed Master’s theses ?>

New group members and completed Master’s theses

We have two new group members who joined us this fall: Prachi Rahate, who is a Master student and works with Dr. Eliana Amazo-Gomez on stellar rotation, and Dr. Andy Gallagher, who is a postdoc and works with Dr. Matthias Steffen on 3D NLTE stellar atmospheres. Welcome! We also had two students successfully complete their Master theses over the summer: Marzie Hosseini completed her thesis on “Transits in the young system PTFO 8-8695, is there a planet?”, as well as…

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Paper on polar flares on fast-rotating M dwarfs ?>

Paper on polar flares on fast-rotating M dwarfs

My PhD student Ekaterina Ilin has discovered a new method to localize flares on fast-rotating stars, using the rotational modulation of flares that last longer than the stellar rotation. With her new method she found that flares on fast-rotating M dwarfs occur close to the poles of the star, instead of neat to the equator like on our own Sun. This could be good news for exoplanets and their habitability, because particles expelled by the star during flares may miss…

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Paper on the X-ray irradiation and evaporation of exoplanets ?>

Paper on the X-ray irradiation and evaporation of exoplanets

Our group’s first paper using data from the German-Russian eROSITA mission has been accepted for publication. My PhD student Grace Foster has investigated the X-ray irradiation and estimated the evaporation of exoplanets using data from eROSITA’s first and second all-sky scan. The paper is available here: Exoplanet X-ray irradiation and evaporation rates with eROSITA Foster, G. ; Poppenhaeger, K. ; Ilic, N. ; Schwope, A. High-energy irradiation is a driver for atmospheric evaporation and mass loss in exoplanets. This work…

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XMM-Newton Workshop on exoplanets and their environments ?>

XMM-Newton Workshop on exoplanets and their environments

This week I am organizing the XMM-Newton 2021 virtual workshop on the topic of “A high-energy view of exoplanets and their environments” as the chair of the Scientific Organizing Committee. We have over 350 participants, which is fantastic! The program and workshop website is here: https://www.cosmos.esa.int/web/xmm-newton/2021-workshop The conference proceedings will be peer-reviewed and published in Astronomische Nachrichten/Astronomical Notes.

Paper on the day-side temperature of KELT-1b, a low-mass brown dwarf ?>

Paper on the day-side temperature of KELT-1b, a low-mass brown dwarf

In a recent work by Prof. Carolina von Essen, with large contributions from our group from the side of Dr. Matthias Mallonn (and minor contributions from myself), we investigate the TESS phase curve and the dayside temperature of KELT-1b, which is a bit too heavy to still be called a planet and is therefore classified as a low-mass brown dwarf. From the abstract: We present the detection and analysis of the phase curve of KELT-1b at optical wavelengths, analyzing data…

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Cool Stars 20.5 ?>

Cool Stars 20.5

Because Zenodo sometimes give a too-many-requests error during the conference, here’s a backup of my conference poster:

Paper on stellar winds blowing around our nearest exoplanet neighbour ?>

Paper on stellar winds blowing around our nearest exoplanet neighbour

A recent work led by our Schwarzschild-Fellow Dr. Julián Alvarado-Gómez shows through numerical simulations that our nearest exoplanetary neighbour experiences a space weather environment similar to our own Earth. The planet is Proxima Centauri c, a planet a few times the size of the Earth, which orbits our nearest stellar neighbour Proxima Centauri in a roughly 5-year orbit. From the abstract: A new planet has been recently discovered around Proxima Centauri. With an orbital separation of ∼1.44 au and a…

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Paper on stellar flares in open clusters ?>

Paper on stellar flares in open clusters

Ekaterina Ilin, a PhD student in my group, has recently published her work on stellar flares in three young and two middle-aged open clusters. From the abstract: “Drawing from the complete K2 archive, we searched 3435∼80 day long light curves of 2111 open cluster members for flares using the open-source software packages K2SC to remove instrumental and astrophysical variability from K2 light curves, and AltaiPony to search and characterize the flare candidates. We confirmed a total of 3844 flares on…

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