Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective

arXiv:2511.08624 · physics.bio-ph, astro-ph.EP · Submitted 2026-08-22 · Read on arXiv

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Introduction to the show: ident: Astrophysics Radio. Generated commentary on the latest astrophysics papers.

Vera: Next we'll be talking about the paper "Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective".

Jocelyn: The paper was written by Andrés Ledesma and Karo Michaelian from Faculty of Science, Universidad Nacional Autónoma de México and Department of Nuclear Physics and Application of Radiation, Instituto de Física, Universidad Nacional Autónoma de México.

Vera: Stay tuned as we take you through the paper and discuss its implications.

The Environmental Constraints: Jocelyn: We’ve defined this mechanism, but how does it work in "Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective" when the environmental conditions are constantly changing? The authors provide a very detailed picture of the Archean surface, detailing things like CO two and CH four levels that were vastly different from today's atmosphere.

Vera: That high concentration of greenhouse gases is important because it allowed the early Earth to maintain a stable climate and provide the energy needed for these photochemical processes to occur at all. We're talking about conditions that support liquid water and chemical reactions.

Jocelyn: The paper highlights that this system of life is operating under non-equilibrium thermodynamics, meaning life is constantly fighting natural decay by maintaining those structured pigments against heat and environmental degradation.

Subrahmanyanyan: It’s not just the stellar input, though; the authors show how a faster rotating Earth could have maintained significant surface temperature gradients which help drive the necessary chemical activity. That rotation changes the thermal landscape.

Vera: That detail about temperature is key for us because it shows that the planet's own physical dynamics are as important as how bright or what kind of light is coming from its star, providing a dynamic feedback loop.

Jocelyn: This suggests that the environment itself must be a complex, shifting system where energy and matter are constantly interacting and rearranging themselves to support these early life forms. We have to model those interactions for us to find the sweet spot.

Subrahmanyanyan: The entire concept shows that we need an environment where energy is constantly being channeled into structures, which is a much more complex task than simply waiting for thermal equilibrium processes to take over.

Vera: As we move forward, we are going to see how this paper starts comparing all the different stellar possibilities against these specific environmental constraints and see what the best candidates are.

The Methodology and Core Findings: Jocelyn: In this segment of "Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective," we're looking at the methodology—how did they test all those diverse star types, from O-class to M-class?

Vera: The authors used a rigorous normalization technique where they fix the total energy input at one thousand three hundred sixty-six W/m squared, which is our solar constant. This ensures that all planets being modeled have the same potential to support liquid water, making the comparison fair.

Jocelyn: This standardization is crucial because it allows us to directly compare the specific photon fluxes across vastly different stellar temperatures, which is exactly what we need for a consistent search strategy. We can’t just look at total power output; we have to look at the quality of light.

Subrahmanyanyan: The paper emphasizes that we must look at the *photon number* flux in specific wavelength bands, quantifying how many photons are available to create and destroy these structures, not just how much energy is present. This is a measure of opportunity for life.

Vera: It’s fascinating because we see that O-type stars produce massive amounts of photons in the destructive hard UV-C region, or band D. This flux is way too high to be useful for the delicate processes they are modeling.

Jocelyn: That’s a major hurdle for us; while O and B stars provide incredible energy, they also offer far too much in the parts of the spectrum that can destroy our potential life forms through ionization. We need protection.

Subrahmanyanyan: This indicates that we need to find a balance—a "sweet spot" where enough soft UV-C is available for structures to form, but not so much hard UV-C is present that the chemical bonds are broken down and degraded.

Vera: Which brings us right into the core finding: the paper suggests that F and G stars are the best candidates for supporting life forms like bacteria, given their energy profiles.

Jocelyn: This gives our future survey strategies a very clear target, focusing on those star types that support this critical balance of energy input rather than just massive amounts of raw power.

Final Conclusions and Implications: Vera: We’ve seen how "Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective" analyzes the viability of life across various stars, highlighting a perspective that is fundamentally different from standard astrobiology surveys. The focus on F, G, and high-mass K-type stars as prime targets is a huge step forward for efficient observation.

Jocelyn: It certainly gives us a highly targeted strategy for our sky surveys, which is exactly what we need when dealing with the vastness of the cosmos. The paper provides a comprehensive roadmap for us, showing exactly which types of environments are conducive to harboring life like ours.

Subrahmanyanyan: The ultimate goal of linking stellar physics to this thermodynamic imperative is a powerful framework, connecting macroscopic properties like stellar mass and lifetime directly to microscopic processes of organizing molecules at the beginning. It shows that the cosmic architecture determines the potential for life's emergence.

Vera: And we’re not ignoring the smaller stars; by recognizing that M-type systems are extremely unlikely to support complex life due to low photon flux, we have gained better constraints on where our resources should be directed in our searches.

Jocelyn: It’s been a genuinely exciting discussion about this paper, and I think it’s going to fundamentally change how we approach our exoplanet surveys entirely by guiding us toward the right stars.

Subrahmanyanyan: We hope this work inspires more detailed models of planetary evolution, connecting the energy budgets of all star types to the origins of life through its thermodynamic constraints.

Vera: The paper has given us a clear path forward, guiding our future work in astrobiology by focusing on continuous, structured dissipation as a way to interpret signs of life.

Jocelyn: It’s been a pleasure discussing "Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective," and I think it's going to be the key reference point for our next big data analysis.

Conclusion: Vera: So, after all that detailed analysis in "Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective," it seems clear that the window for life like ours is remarkably narrow when we consider the star's entire spectral output.

Jocelyn: It really narrows down our observational focus to those F and G-type stars, as well as high-mass K-types, which offer that perfect balance of energy without excessive degradation from hard UV.

Subrahmanyanyan: I think it’s a profound confirmation that the physical conditions—the star's temperature and its lifetime—are fundamentally dictating whether or not life has the opportunity to emerge through this dissipative structuring.

Vera: It also gives us much better parameters for M-type stars; we can confidently say they are extremely unlikely to host complex life because their photon fluxes are simply too low.

Jocelyn: And that’s a huge win for our survey planning, knowing exactly where to allocate those limited telescope hours based on this theoretical groundwork.

Subrahmanyanyan: The entire model shows that the drive toward energy dissipation is not just a chemical byproduct but the actual engine of evolution itself, from simple pigments to complex organisms.

Vera: It’s a fascinating idea, and I think it sets up such a compelling framework for how we interpret any potential biosignatures in the future.

Jocelyn: We're really looking forward to seeing how this "dissipative structuring" manifests in actual observations, perhaps through those low soft UV-C albedo values they mentioned.

Subrahmanyanyan: I remain excited about the implications of linking macroscopic stellar properties to microscopic prebiotic chemistry, as detailed in the paper.

Vera: This entire discussion of "Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective" has given us so much concrete data to work with.

Jocelyn: It’s definitely going to influence how we think about the search for life in different stellar environments, right?

Subrahmanyanyan: I agree, it gives us a very strong theoretical basis for our future models.

Vera: Well, let's transition now and look at some more recent data from the JWST...

Andrés Ledesma, Karo Michaelian

Faculty of Science, Universidad Nacional Autónoma de México · Department of Nuclear Physics and Application of Radiation, Instituto de Física, Universidad Nacional Autónoma de México

physics.bio-ph, astro-ph.EP

Submitted: 2026-08-22

Updated: 2026-08-25

Comments: 33 pages, 13 figures

License: http://creativecommons.org/licenses/by/4.0/

Importance score: 28/100

The gist: * Abstract and Theoretical Framework (TDTOL) The paper begins by outlining the "thermodynamic dissipation theory for the origin of life" (TDTOL), which asserts that "the fundamental molecules of life

Key concepts

Non-equilibrium thermodynamics: This describes a system where life constantly fights natural decay by maintaining structured pigments against heat and environmental degradation. It means life is not in a stable state but is actively working to maintain its structure against external forces.
Dissipative structuring: The model shows that the drive toward energy dissipation is the actual engine of evolution, from simple pigments to complex organisms. Energy must be constantly channeled into structures rather than just waiting for thermal equilibrium processes.
Photon number flux: This is a measure used to quantify how many photons are available in specific wavelength bands. The paper emphasizes this over total energy input because it measures the actual opportunity for life to create and destroy chemical structures.
Sweet spot: This refers to the necessary balance of stellar energy input. It is the point where enough soft UV-C is available for structures to form, but not so much hard UV-C that chemical bonds are broken down and degraded.

Terminology

Absorption Cross Section — 4× in this paper · explained in 1 episode
Abundance — 2× in this paper · explained in 1 episode
Core — 2× in this paper · explained in 2 episodes
Metallicity — 2× in this paper · explained in 3 episodes
Ab Initio — 1× in this paper · explained in 1 episode
Adam — 1× in this paper · explained in 2 episodes
Degeneracy — 1× in this paper · explained in 3 episodes

Summary

Abstract and Theoretical Framework (TDTOL)

The paper begins by outlining the thermodynamic dissipation theory for the origin of life (TDTOL), which asserts that "the fundamental molecules of life originated as self-organized molecular photon dissipative structures (chromophores or pigments) that proliferated over the ocean surface to absorb and dissipate into heat the Archean solar 'soft' UV-C (205-285 nm) and UV-B light (< 320 nm) of our G-type star."

TDTOL posits that the dissipative structuring of organic chromophores under light is the fundamental creative force in biology, leading to the emergence of complex life forms like photosynthesis at visible wavelengths. This process relies on a specific electromagnetic spectrum: a very particular region... limited on the long-wavelength side by the strength of molecular covalent bonding and on the short wavelength side by molecular ionization energies, is required for abiogenesis.

Methodology and Criteria

The aim of the paper was to determine which star types are conducive to providing this light environment for life similar to our own. The analysis considered planets orbiting their star type at a distance where its stellar constant equals our solar constant, ensuring conditions suitable for liquid water and similar chemical reaction rates.

The viability of a star type is determined by analyzing the ratio of integrated photon fluxes in the soft UV-C wavelength region (dissipative structuring, 205–320 nm) to the hard UV-C wavelength region (degradation, 10–205 nm).

Key Findings on Star Types

The analysis of various main-sequence star types (O, B, A, F, G, K, and M) reveals significant differences in their spectral outputs:

O and B-Type Stars: These stars exhibit extremely high photon fluxes in the destructive ionization region. The results show very low molecular steady state concentrations, with O-type stars having fluxes that are 4 orders of magnitude greater than G-type stars in the destructive region, leading to little probability of this important precursor [HCN] raining down to the surface on such a planet. Furthermore, these stars have extremely short lifetimes: less than 0.005 Ga, making it highly improbable for complex life forms like bacteria to evolve.
A-Type Stars: While they can live long enough (may live long enough about 1 Gyr), the their "greater than one order of magnitude higher hard UV-C (< 205 nm) radiation" could cause problems for incipient life.
F and G-Type Stars (Most Favorable): These stars are deemed the most adequate for the appearance of life like our own. They are characterized by:
high stationary state concentrations of the fundamental molecules.
Short timeframes to reach these states (a few months).
low rates of X-ray, FUV or particle outbursts.

They have sufficient longevity and stability for the evolution of bacteria and complex ecosystems. However, their shorter stellar lifetimes (F-type about 2 Ga) suggest that intelligent human-like civilizations probably only arise on G-type stars.

K-Type Stars: These stars face several impediments:
Frequent outbursts of high intensity short wavelength FUV, X-rays and high energy particles with average periods of only days could degrade chromophores formed in the soft UV-C.
Tidal locking of planets on lower mass K-type stars... would not occur, which is necessary for the diurnal cycling of the UV-C light required for life's evolution.
M-Type Stars: These stars are highly unfavorable. They have very low stationary concentrations of the fundamental molecules (less than 10-7 that of G-type stars), and they require very long times (years) to reach even these very low concentrations. They are also subject to frequent outbursts and tidal locking.

Conclusion on Astrobiological Search Targets

The paper concludes that, based on the TDTOL framework:

astrobiologists should concentrate their searches for bacterial biosignatures only on F, G and higher mass K-type stars.
biosignatures of intelligent life only on G and high mass K-type stars.

The authors propose a proxy biosignature—the soft UV-C planet albedo—as a measurable indicator of the existence of carbon based life, which should remain low throughout the evolution of life due to the presence of primordial UV-C pigments.

Improvements for AI systems

The following improvements outline how an advanced AI system can be enhanced using the detailed physical models and empirical data presented in this paper, enabling it to perform highly specific astrobiological simulations and predictive analysis.

Improvement: Develop a specialized Exoplanet Viability Simulator that integrates the core dynamic equations from Section 8.1 (the concentration dynamics of fundamental molecules under light/dark cycles) with the spectral data from Tables 3 and 4 (photon fluxes P and D).

What the Improved AI System Can Do:

Simulate Chemical Evolution: Calculate the exact time required for a planet orbiting any star type (O, B, A, F, G, K, M) to reach a specific target concentration of a fundamental molecule (e.g., 10-9 M), given varying chemical degradation rates (k).
Determine Viability Threshold: Predict the minimum required photon flux (P) for a given star type to overcome the combined effect of photodegradation (D) and chemical decay (k) to sustain a viable concentration of life-building pigments.
Assess Atmospheric Resilience: Model how changes in atmospheric composition (e.g., increased CO 2 or H 2 O density) alter the calculated surface spectral flux for a specific star type, predicting whether the resulting surface spectrum still falls within the soft UV-C window (205–320 nm).

Abstract

From the non-equilibrium thermodynamic perspective of the origin of life as a photochemical dissipative structuring (entropy driven) process, we assess the probability of carbon-based life arising on Earth-like analogues orbiting different main-sequence stellar types (O7 V to M2 V). Using black-body spectra normalized to Earth's solar constant, we calculate surface photon fluxes for an atmosphere like early Archean Earth's in the productive dissipative structuring (P, soft UV-C + UV-B, 205-320 nm) and destructive ionization (D, hard UV-C + EUV, <205 nm) regions. Stationary concentrations of fundamental molecules and times to reach 99% of these are computed for different chemical degradation (e.g., deamination, hydrolysis, oxidation, etc.) rate constants of k = 10-7, 10-6, and 10-5 s-1. For a nominal chemical degradation rate constant of k = 10-6 s-1 (t 1/2= 8 days), results show F-, G-, and K-type stars provide the highest stationary concentrations of fundamental molecules and short rise times (weeks to months), while quiescent M-type stars yield extremely low concentrations (10-7 relative to G stars) and require years to reach even these values. Flaring M stars improve stationary concentrations by about an order of magnitude (10-6 relative to G stars) but produce adverse planet surface environments for complex evolution through dissipative structuring. From this non-equilibrium thermodynamic perspective, carbon-based life like Earth's is to be found most probably on F-, G-, and high-mass K-type stars, with intelligent life arising only on G-type stars. Low mass K- and M-dwarfs are highly unlikely to harbor life unless seeded via panspermia. Biosignatures related to the thermodynamic imperative of photon dissipation are proposed.