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Reposted by Baptiste Klein

Planets @ Oxford @oxoplanets.bsky.social · 30/03/2026

Congratulations to Dr Baptiste Klein (@astroklein.bsky.social) on his talk at #UKExoM meeting in Bristol. He explains how he accounts for stellar variability when studying exoplanets at high resolution!

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Reposted by Baptiste Klein

Linn Boldt-Christmas @nplinnspace.bsky.social · 27/08/2025

Do you love WASP-107 b? Do you love making use of *both* ground VLT + space JWST obs to detect molecules in a "warm" (Teq<800K) #exoplanet in transmission, even in a crazy confusing cloudy atmosphere?! 🚨 It's PAPER* DAY! Which means #scicomm thread! 🧵⬇️🔭🪐🧪 *pre-print! arxiv.org/abs/2508.18964

arxiv.org

VLT/CRIRES+ observations of warm Neptune WASP-107 b: Molecular detections and challenges in ground-based transmission spectroscopy of cooler and cloudy exoplanets

Atmospheres of transiting exoplanets can be studied spectroscopically using space-based or ground-based observations. Each has its own strengths and weaknesses, so there are benefits to both approache...

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Baptiste Klein @astroklein.bsky.social · 28/08/2025

Big thanks to HARPS-N solar team and science team, and to TNG staff for processing the data and maintaining the solar telescope!!

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Baptiste Klein @astroklein.bsky.social · 28/08/2025

Could Doppler Imaging be a reliable alternative to radial-velocity-based activity modelling techniques? Maybe.. but we will have a develop an operational version of the code! Please contact me if you want to collaborate on this!

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Baptiste Klein @astroklein.bsky.social · 28/08/2025

We inject exoplanet signatures into the HARPS-N solar spectra, and use Doppler Imaging to retrieve these whilst modelling stellar activity. We show that, in the case of a super Earth on a 100-day orbit, the mass is retrieved with an accuracy at least as good as 2D Gaussian Processes!

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Baptiste Klein @astroklein.bsky.social · 28/08/2025

Our code pick up quite well the large structures of disc-resolved Dopplergrams of the Sun with SDO/HMI! Understanding what exact physical is picked up will need more work though!

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Baptiste Klein @astroklein.bsky.social · 28/08/2025

In Doppler Imaging, we model the distortions of a star's spectral lines caused by magnetically-active regions at the stellar surface. We invert them into a full low-resolution map of the stellar surface brightness. We bypass the radial velocity computation!

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Baptiste Klein @astroklein.bsky.social · 28/08/2025

Very excited to share that my new paper has been accepted for publication in MNRAS! We are applying Doppler Imaging to model the activity signals from the HARPS-N Sun-as-a-star spectra! We show that injected planets can be retrieved with great accuracy! ui.adsabs.harvard.edu/abs/2025MNRA... 🔭🪐🧪

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