Juliette Becker

Dynamical Interactions and Habitability in the TOI-700 Multi-planet System Dynamical Interactions and Habitability in the TOI-700 Multi-planet System, Nelson, Coleman, Becker, Juliette

New paper led by University of Wisconsin-Madison undergrad alum Coleman Nelson finds TOI-700d is robustly habitable, while TOI-700e sits on the edge: iopscience.iop.org/article/10.1...

Warm Jupiter Tidal Migration Can Spare Inner Planets; Hot Jupiter Tidal Migration May Not Warm Jupiter Tidal Migration Can Spare Inner Planets; Hot Jupiter Tidal Migration May Not, Becker, Juliette

...with high-e migration, but warm Jupiters may be a narrow sweet spot.
iopscience.iop.org/article/10.3... #exoplanets

Warm Jupiter Tidal Migration Can Spare Inner Planets; Hot Jupiter Tidal Migration May Not Warm Jupiter Tidal Migration Can Spare Inner Planets; Hot Jupiter Tidal Migration May Not, Becker, Juliette

New ApJ paper: Can inner planets survive when a giant becomes a hot/warm Jupiter via high-eccentricity tidal migration? Usually no. Survival requires the giant’s periastron to stay >14 mutual Hill radii away. Observed systems with hot Jupiters + inner planets are inconsistent...

AbSciCon will be in Madison, WI in May 2026! Please consider submitting an abstract to session 39, Dynamical Environments of Habitable Worlds, led by Joseph Livesey.

Hope to see you all there!

I use that paper all the time! I can't believe it was almost rejected!!

Interested in coming to UW-Madison and working with WiCOR on questions related to the origin of life? Apply for this new postdoctoral fellowship opportunity. Applications due November 15th!

If you are hiring this fall, keep an eye out for Marguerite Epstein-Martin, a dynamicist who works across 10^8 orders of magnitude in central body mass!

Marguerite's previous work spans time-evolution of AGN disks to secular resonances in young protoplanetary disks. In this new paper, she computes where in AGN disks stellar-mass BH binaries may survive, and when they will be stochastically forced out of resonance.

Mean Motion Resonances in AGN Disks Mean motion resonances (MMRs) are a generic outcome of convergent migration for bodies embedded in accretion disks around a central mass. Long studied in planetary systems, the same phenomenon should ...

Mean motion resonances (familiar from planetary systems) also govern how stellar-mass BHs migrate and merge in AGN disks. Marguerite Epstein-Martin (applying to postdocs THIS FALL) has a new paper “Mean Motion Resonances in AGN Disks” (arxiv.org/abs/2510.128...). #exoplanets

Investigating the Formation of Planets Interior to in situ Hot Jupiters The population of hot Jupiters with adjacent planetary companions is small but growing, and inner companions appear to be a nearly ubiquitous outcome within this subset of the exoplanet census. While ...

Some hot Jupiters might not have traveled far.
New simulations by UW-Madison recent undergrad alum Devansh Mathur show that if enough solid material is funneled inward, both a hot Jupiter and its inner companions could form in situ. Accepted to PASP: arxiv.org/abs/2510.135... #exoplanets

I also wrote a blog post with a level of detail in between this post and the paper itself: becker.astro.wisc.edu/2025/10/09/n...

General Relativity Can Prevent a Runaway Greenhouse on Potentially Habitable Planets Orbiting White Dwarfs Planets orbiting in the habitable zones of white dwarfs have recently been proposed as promising targets for biosignature searches. However, since the white dwarf habitable zone resides at 0.01 - 0.1 ...

Published this week in ApJ by UW-Madison undergraduate Eva Stafne: General relativity might save life on planets orbiting white dwarfs. GR-driven orbital precession can suppress tidal heating that would otherwise trigger a runaway greenhouse. arxiv.org/abs/2509.26421 #exoplanets

I am an assistant professor at UW-Madison in the Department of Astronomy, and would like to share new research results.

yes

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So if you want the water to survive, the planet has to migrate late enough that the white dwarf has cooled and is not so bright in the XUV.

Losing mass loss via Jeans escape is actually not easy (thermolysis occurs at 2000 K or hotter, and bonded H20 is very heavy and hard to lose). Photoevaporation will make the water vapor escape very easily, and white dwarfs are luminous in the XUV when young...

Great question - we actually wrote a paper addressing just this: ui.adsabs.harvard.edu/abs/2025ApJ.... You are 100% right that this process requires high ecc and will cause tidal heating. The main effect (on water) of the tidal heating is to evaporate liquid water into the atmosphere as water vapor.

Earth-size stars and alien oceans – an astronomer explains the case for life around white dwarfs Could tiny stars a fraction the size of our solar system’s Sun have habitable planets orbiting them? A new study says it’s possible.

When stars die, could life begin? White dwarfs could possibly host planets with oceans, making them worth considering in the search for life.

I wrote about the science (and surprises) of white dwarf planets at The Conversation. theconversation.com/earth-size-s...

Two weeks until abstracts (and requests for travel support) are due for this fall's GLEAM! gleam.astro.wisc.edu/overview/ I hope to see you here!

We’re so happy to host GLEAM 2025 at UW–Madison this Fall, Nov 6–7! gleam.astro.wisc.edu Join us for two days of exoplanets & community with a view of the shores of Lake Mendota. No registration fee. Travel support available. Abstracts & Travel Support Requests due Sept 5th. #exoplanets

Definition question: Everyone in the field seems to use P~10 days as the boundary between "Hot" and "Warm" Jupiters in the literature. Does anyone know where this boundary actually came from (did a single person come up with it, and if so who / what paper)?

#AAS246 Chambliss Student Award Winners

The AAS is pleased to announce the Chambliss Astronomy Achievement Student Award winners from the 246th AAS meeting in Anchorage, Alaska, in June 2025. Congratulations, all! aas.org/posts/news/2... 🔭

From Earth to Exoplanets: Studying Oceans Across the Universe

AOS Prof. Hannah Zanowski studies polar oceanography, and she's now bringing that expertise to WiCOR, where she focuses on planetary oceanography by modeling early Earth and exoplanet conditions to understand what ultimately makes a planet habitable after it forms.

ls.wisc.edu/news/from-ea...

Habitability and Biosignatures of Hycean Worlds We investigate a new class of habitable planets composed of water-rich interiors with massive oceans underlying H2-rich atmospheres, referred to here as Hycean worlds. With densities between those of ...

Good question!! And Svetoslav is right, previous work by Madhusudhan et al. (arxiv.org/abs/2108.10888) found that Hycean planets are actually likely habitable to much lager distances due to their large masses which lead to large pressure & subsurface ocean (even if the top layer is ice, like Europa)

Congratulations, Irene, on this excellent (and very complete) paper!!

Measuring gases around young stars, astronomers unlock major clues to planet formation UW–Madison astronomers and international collaborators have produced the most accurate measurement of the gases swirling around young stars and their changing mass over time. The discovery offers clue

'Baby' stars are typically surrounded by disks loaded with gas, but it isn't long before that mass starts to drift away. #UWMadison astronomers say that might mean gas giants like Jupiter need to form earlier than rocky planets like ours. news.wisc.edu/measuring-ga...

Tides Tighten the Hycean Habitable Zone Hycean planets -- exoplanets with substantial water ice layers, deep surface oceans, and hydrogen-rich atmospheres -- are thought to be favorable environments for life. Due to a relative paucity of at...

What does that mean? If a Hycean planet has a giant outer companion, tidal forces can perturb it out of the habitable zone, even if the incident stellar flux looks fine. You can find the accepted paper here:

Here is a plot from Joseph's paper showing the effect - the transparent region was the location of the known habitable zone, the opaque region is the updated limits including tidal heating. For low mass stars, tides can make a difference!

In a new paper accepted to ApJ Letters and on arXiv now, UW-Madison graduate student Joseph Livesey (astro.wisc.edu/staff/livese...) shows that tidal heating from even modest orbital eccentricity can heat close-in planets around M-dwarfs, shrinking the habitable zone significantly.