Evan Anders

KITP Postdoctoral Scholar

AI Research

I recently realized that AI is going to transform the way that we live and work. I want to be a part of a team that makes sure our transition into the AI era goes well! So I'm starting research on AI safety, specifically doing some small Mechanistic Interpretability projects. Check out my blog to see what I've been working on recently: https://evanhanders.blog/.

Astrophysics Research

I am a postdoctoral scholar at UCSB's KITP institute. I previously worked on astrophysical fluid dynamics. I broke down questions from astrophysical observations into simple fluid dynamical experiments to learn more about dynamics in the Sun and other stars. Some movies of my work are available online on my vimeo page; a select few are below.

Recent Project 1: Surface Manifestation of Gravity Waves

I recently studied the surface manifestation of gravity waves generated by core convection in massive stars. Convection at the core of a massive star hits the surrounding stable region like a drum, launching waves. These waves may be observable at the stellar surface, and could be used to tell us about the properties of the inside of the star. See below for a video of some simulations of the insides of a 15 solar mass star.

Recent Project 2: Convective Boundaries & Penetrative Convection

Observations suggest that theoretical models underestimate the amount of mixing near the boundaries of convection zones in stars. I recently discovered that a process called "penetrative convection" might be responsible for this discrepancy. A video of a simulation of this process (between the solid black line and dashed line) is shown below.

Recent Project 3: Convective Boundary Evolution

I worked to verify the validity of prescriptions for treating the evolution of convective boundaries in 1D stellar evolution models using 3D hydrodynamical simulations. Below is a movie of the evolution of a convective boundary. The orange "Ledoux" boundary roughly determines the maximum height where vigorous convection is present, but over time convection mixes low-density (purple) fluid into the convective region. This mixing expands the convection zone, until the size of the zone is determined by the the purple "Schwarzschild" boundary.

Fun Stuff

Sometimes I studied Moosive stars.

Publications (updated September 2023)

ADS Author Library

Google Scholar Profile

arXiv Author Query

Powers, W. T., Anders, E. H., and Brown, B. P. 2023. "Internally heated and fully compressible convection: flow morphology and scaling laws." Submitted to PRF.

Cresswell, I. G., Anders, E. H., et al. 2023. "Force Balances in Strong-Field Magnetoconvection Simulations". Accepted for publication in PRF.

Anders, E. H. et al. 2023. "The photometric variability of massive stars due to gravity waves excited by core convection." Nature Astronomy.

Tripathi, B. et al. (6th author). "Nonlinear mode coupling and energetics of driven magnetized shear-flow turbulence." PoP 30, 072107.

Fuentes, J. R., Anders, E. H., Cumming, A., and Hindman, B. W. 2023. "Rotation reduces mixing of composition gradients in Jupiter and other gas giants." ApJL 950, L4. [ADS]

Fuentes, J. R. et al. (4th author) 2023. "Heat transport and convective velocities in compositionally-driven convection in neutron star and white dwarf interiors." ApJ 950, 73. [ADS]

Anders, E. H. and Pedersen, M. G. (co-first-author) 2023. "Convective boundary mixing in main-sequence stars: theory and empirical constraints." Galaxies 11(2), 56. [ADS]

Fraser, A. E., et al. (co-first-author). 2022. "Characterizing Observed Extra Mixing Trends in Red Giants using the Reduced Density Ratio from Thermohaline Models." ApJ 941, 164. [ADS]

Fuentes, J. R., Cumming, A., and Anders, E. H. 2022. "Layer formation in a stably-stratified fluid cooled from above. Towards an analog for Jupiter and other gas giants." [ADS]

Kaufman, E., et al. (3rd author). 2022. "The Stability of Prendergast Magnetic Fields". MNRAS 517, 3. [ADS]

Jermyn, A. S., Anders, E. H. , et al. 2022. "An Atlas of Convection in Main Sequence Stars." ApJS 262, 19. [ADS]

Jermyn, A. S., Anders, E. H. , et al. 2022. "Convective Penetration in Early-Type Stars." ApJ 929, 182. [ADS]

Anders, E. H. et al. 2022. "Scwharzschild and Ledoux are equivalent on evolutionary timescales." ApJL 928, L10. [ADS]

Jermyn, A. S., Anders, E. H., Cantiello, M. 2022. "A Transparent Window into Early-Type Stellar Variability." ApJ 926, 221. [ADS]

Anders, E. H. et al. 2022. "Stellar convective penetration: parameterized theory and dynamical simulations." ApJ 926, 169. [ADS]

O'Connor, L., Lecoanet, D., Anders, E. H.. 2021. "Marginally-Stable Thermal Equilibria of Rayleigh-Bénard Convection." PRF 6, 093501 [ADS]

Lecoanet, D. et al. (3rd author). 2021. "Surface Manifestation of Stochastically Excited Internal Gravity Waves." MNRAS 509, 1, 132-143. [ADS, arXiv]

Van Kooten, S. J., Anders, E. H., and Cranmer, S. R. 2021. "A Refined Model of Convectively-Driven Flicker in Kepler Light Curves." ApJ 913, 69. [ADS, arXiv]

Oishi, J. et al. (4th author). 2021. "eigentools: A Python package for studying differential eigenvalue problems with an emphasis on robustness." JOSS 6(62), 3079.

Anders, E. H., Vasil, G. M.; Brown, B. P.; Korre, L. 2020. "Convective dynamics with mixed temperature boundary conditions: why thermal relaxation matters and how to accelerate it." Published in PRFluids. [ADS, arXiv]

Anders, E. H., Lecoanet, D. and Brown, B. P. 2019. "Entropy Rain: Dilution and Compression of Thermals in Stratified Domains." Published in ApJ. [ADS, arXiv]

Anders, E. H.; Manduca, C. M.; Brown, B.P.; Oishi, J. S.; and Vasil, G. M.. 2019. "Predicting the Rossby number in convective experiments." Published in ApJ. [ADS Bumblebee, ADS Classic, arXiv]

Anders, E. H., Brown, B. P., and Oishi, J.S., 2018. "Accelerated evolution of convective simulations." Published in PRFluids. [ADS Bumblebee, ADS Classic, arXiv]

Anders, E. H. and Brown, B. P., 2017. "Convective heat transport in stratified atmospheres at low and high Mach number." Published in PRFluids. [ADS Bumblebee, ADS Classic, arXiv]

Karki, S. et al. (6th author), 2016. "The Advanced LIGO Photon Calibrators." Review of Scientific Instruments (Vol 87, Issue 11). [ADS Bumblebee, ADS Classic, arXiv]