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Home — cogsworth documentation

Excited to get started? The online documentation (cogsworth.readthedocs.io/en/latest/) includes nearly 20 tutorials, a gallery of quick examples and several in-depth case studies to give you everything you need to become a cogsworth expert in no time 😎 Can't wait to see what you do with it!

cogsworth.readthedocs.io

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cogsworth is built on top of the COSMIC and Gala codes, letting you access any of the awesome features in those packages through cogsworth. I'm so grateful for my wonderful co-authors Katie Breivik, Mathieu Renzo and @adrian.pw on this project who made it a joy to work on!

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Speaking of visualisations, tired of interpreting evolutionary tables full of numbers? Use cogsworth to make your life easier and simply dynamically generate a cartoon evolution diagram for any binary in your simulation, and quickly plot it's orbit through the galaxy.

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cogsworth also comes equipped and ready to transform intrinsic distributions to observables by applying dust maps, bolometric correction functions and selection functions to your simulations. You can directly produce a CMD of your populations with one simple function!

You can even start a cogsworth simulation based on a hydrodynamical zoom-in simulation, sampling clustered populations and fitting a potential to the galactic mass distribution. We currently support any FIRE-2 or ChaNGa galaxy, here's an example from FIRE m11h!

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Want to define your own custom star formation like the plot below? cogsworth supports it! Want to change a myriad of binary physics assumptions? cogsworth has you covered! Curious how your systems evolve in different galactic potentials? cogsworth can tell you!

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Where did every supernova in a given galaxy happen? Where are the r-process enrichment sites? cogsworth can not only simulate all of this, but also demonstrate how your results change for different assumptions about star formation, binary physics and the galactic environment!

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The core purpose of cogsworth is to make predictions for the positions and kinematics of massive stars and compact objects. Both binary evolution and galactic dynamics strongly affect these parameters - and so they have a lot of constraining potential!

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Home — cogsworth documentation

Excited to share the release of my new code cogsworth (cogsworth.readthedocs.io/en/latest/) that YOU can use to make seamlessly self-consistent population synthesis and galactic dynamics simulations! The paper is out on arXiv (arxiv.org/abs/2409.04543) but read on here for more details 🥳

cogsworth.readthedocs.io

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Reposted by Tom Wagg

Brett Morris @brettmorr.is · 12/03/2024

Ringo asked, "What would you do if I sang out of tune, would you stand up and walk out on me?" He didn't know that sometimes the stars sing out of tune because they've consumed their siblings. @tomwagg.bsky.social shows us how to hear the music of stellar satiety: 🔭🧪 arxiv.org/abs/2403.05627

arxiv.org

The Asteroseismic Imprints of Mass Transfer: A Case Study of a...

We present new simulations investigating the impact of mass transfer on the asteroseismic signals of slowly pulsating B stars. We use MESA to simulate the evolution of a binary star system and...

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A huge thanks to my co-authors and the organisers of the Kavli Summer Program where we developed this project, it’s been lots of fun!!

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In summary: mass transfer leaves significant imprints on asteroseismic signals throughout the main sequence and this provides opportunities for studying binary physics…but also implies a need for caution when fitting stars. Future work should explore a range of accretor models!

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Check out the paper for more details on: (a) where/how the mass transfer signature shows up, (b) why inferring stellar ages of accretors will always be problematic and (c) some discussion of the limitations of our model.

We show how this means that one could potentially infer an incorrect mass or central hydrogen abundance for a star if you assume it is a single star when in reality it has accreted mass. The posteriors are extremely multi-modal so care needs to be taken in fitting.

$Chi^2 distribution for fitting our accretor model with a single star grid in mass and central hydrogen fraction$

This has a strong effect on the observed period spacing pattern of an accretor star. Pulsation modes that are sensitive to the region with an altered structure show shifts in both period and amplitude compared to an equivalent single star. (e.g. look at the Xc=0.1 panel between 1.5 and 3 days)

Period spacing pattern of an accretor star and equivalent single star

Central idea: the convective core of the star adjusts as it accretes mass, this alters the internal structure of the star, leaving a kink in the chemical composition gradient. We find this signature of mass transfer stays present in the star throughout its main sequence!

We used MESA & GYRE to simulate the asteroseismic signals of a 3Msol star that accretes mass from a 4Msol binary companion (~the mass range of Slowly Pulsating B stars). Here’s an HRD of their evolution (accretor highlighted in green).

Hertzsprung-Russel diagram of an interacting binary

First off, you don’t just need to stare at my plots, head over to www.tomwagg.com/html/interac... to interact with them and understand what’s going on in detail!

Paper day today! 🎉 So excited to share this work investigating how mass transfer leaves imprints on the asteroseismic signals of a star: arxiv.org/abs/2403.05627. More in the thread below! 🧵

Hertzsprung-Russell diagram of an interacting binary

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