Hedorah, the first yellow supergiant Kaiju star candidate at z=3.7 revealed by JWST behind AS1063

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

Vera: Next we'll be talking about the paper "Hedorah, the first yellow supergiant Kaiju star candidate at z=3.7 revealed by JWST behind AS1063".

Jocelyn: The paper was written by J.M. Diego, J.M. Palencia, C. Goolsby, C.J. Conselice, D.J. Lagattuta et al. from Instituto de Física de Cantabria (CSIC-UC) and Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester and Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire and STAR Institute, Quartier Agora - Allée du six Août, 19c B-4000 Liège, Belgium. and Université Claude Bernard Lyon 1, CRAL UMR5574, ENS de Lyon, CNRS, and Department of Astronomy, University of Michigan and School of Physics and Astronomy, University of Minnesota.

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

Paper discussion segment 1: Vera: We've been looking at this incredible paper, "Hedorah, the first yellow supergiant Kaiju star candidate at z=three point one revealed by JWST behind AS1063," which has us all buzzing. Jocelyn, it's hard to not be fascinated by the fascination with the following pop culture reference to a monster-sized star.

Jocelyn: It really is, Vera. J.M. Diego and his team of researchers from institutions like the Instituto de Física de Cantabria in Spain and University of Manchester in UK, represent a paper that is a massive international collaboration. This kind of global teamwork is what it takes to analyze the such deep JWST data from the cluster AS1036.thought

Subrahmanyan: This paper's title isn't just being playful; it signals that we are looking at something extremely rare and sometimes quite extraordinary in the early universe. Finding a yellow supergiant at a redshift of three point one is essentially finding a finding a finding a finding a finding a finding a finding

Vera: Exactly, Subrahmanyan. Most of the lensed stars we've seen so far with JWST has been red or blue supergiants, so this "Hedorah" star candidate is an anomaly that challenges our understanding of stellar evolution at high redshift.

Jocelyn: And it's not just about one star; the title also mentions AS1063, which is the galaxy cluster acting as our natural telescope. By using this cluster to lens the background star, and its magnification, we little bit of a little bit of a little bit of a little bit of a little bit of a little bit of a little bit

Subrahmanyan: The implications for cosmology are massive. If Hedorah is indeed a yellow supergiant or hypergiant, it tells us about the mass and metallicity of the first generations of stars. It's like having a probe into the very early universe, scanning parsec-scale fluctuations in theaging process of stellar populations.

Vera: I love how they used that cluster as a magnifying glass to see something thats so distant it would otherwise be completely invisible. We're moving from just seeing galaxies to seeing individual stars across cosmic time.

Jocelyn: It's a huge leap in observational capability, Vera. I wonder what else is hiding in those deep JWST images?

Subrahmanyan: There is a whole spectrum of possibilities, from little-red-dots to extreme emission line galaxies.

Vera: That leads us perfectly into the next part of our discussion, where we'll look at the actual summary and findings of this study.

Paper discussion segment 2: Vera: Now that we've touched on the title and why it's so catchy, let's look at what J.M. Diego and his team actually discovered in "Hedorah, the first yellow supergiant Kaiju star candidate at z=three point one revealed by JWST behind AS1063."

Jocelyn: The summary of the paper is quite dense, but essentially, they've used ultra-deep JWST data to build a new free-form lens model for the cluster AS1063. This model is critical because it allows them to identify new counterimages and confirm previously known lensed systems.

Subrahmanyan: This modeling is the backbone of the science, Jocelyn. Without a highly precise lens model, you can't accurately determine magnification or geometric redshift. Without it, these "monster" stars are just blurry blobs in your data.

Vera: I was struck by their identification of a peculiar multiply lensed galaxy at z approximately seven point five with strong emission lines. They describe it as either an extreme emission line galaxy or a little-red-dot, which is such an intriguing find!

Jocelyn: And they also found that Hedorah itself has very unique photometry. It's undetected in the F090W filter and shows significant emission in the F150W band, which is consistent with a temperature of about six thousand five hundred Kelvin. That really points toward it being a yellow supergiant.

Subrahmanyan: The fascinating part is that Hedorah doesn't have a visible counterimage on the other side of the CC. The This could be due to microlensing or intrinsic variability, like if it's a Cepheid variable star.

Vera: That's a great point, Subrahmanyan. They even explore the possibility that Hedorah is part of a small group of stars rather than a single star, though they argue that's less likely given its colors.

Jocelyn: It sounds like the data is incredibly revealing, but I wonder if there we are seeing something more exotic than just a single star.

Subrahmanyan: That could be the case; they even discuss how fuzzy dark matter could explain the lack of a counterimage by creating parsec-scale fluctuations in magnification.

Vera: We'll have to dig into that in our next segment when we talk about the improvements and implications of their work.

Paper discussion segment 3: Vera: We've just talked about the discoveries and the strange nature of Hedorah, so let's look at how this paper, "Hedorah, the first yellow supergiant Kaiju star candidate at z=three point one revealed by JWST behind AS1063," suggests improvements for our future studies.

Jocelyn: One of the biggest improvements is the method they used to build their lens model. They used a hybrid type of modeling technique that combines a smooth, large-scale component with small-scale contributions from cluster galaxies. This provides much more detail than older models could offer.

Subrahmanyan: This precision is vital for future work, Jocelyn. As we get more data from JWST and eventually the ELT, we'll be able to to use these lensed stars as "pencil beams" to scan the small-scale fluctuations in the lensing potential, which can tell us about dark matter on a parsec scale.

Vera: I love how they highlight that finding a Cepheid at high redshift would be a unique opportunity for cosmology. If we can confirm Hedorah is a Cepheid, it would provide an independent constraint on H0 that doesn't rely on SNe.

Jocelyn: But as the paper points out, using lensed Cepheids as standard candles has its own set of challenges, specifically the stochastic distortion in magnification from microlenses.

Subrahmanyan: Exactly, Jocelyn. The magnification is a huge variable, and you have to account for both the macromodel and the microlensing effects if you want to use them as standard candles.

Vera: They also suggest that more deep multi-epoch observations of AS1063 with JWST are needed to confirm whether Hedorah is a microlensing event or an intrinsically variable star.

Jocelyn: So, the path forward involves more time and more deep imaging, but it's a wonderful start.

Subrahmanyan: It's the beginning of a new era where we can see individual stars in the distant universe.

Vera: And that brings us to our final segment where we'll wrap everything up.

Conclusion: Vera: We've had such a fascinating discussion today about "Hedorah, the first yellow supergiant Kaiju star candidate at z=three point one revealed by JWST behind AS1063." It's been an absolute pleasure walking through this research.

Jocelyn: It really has, Vera. The way they used the cluster AS1063 as a natural telescope to find Hedorah is just incredible. Seeing a single star at such a high redshift is something we truly've never seen before.

Subrahmanyan: This paper marks an important milestone in our understanding of stellar evolution and the possibility of using lensed stars as cosmological probes. Whether Hedorah is a single monster star or a group of stars, it's teaching us something new about the cosmic history of the scale.

Vera: And if it's confirmed as a Cepheid, it's an incredible discovery that could reshape our understanding of the cosmic distance ladder.

Jocelyn: I can't wait to see what future observations confirm these findings. The science is truly moving at a very rapid pace with JWST.

Subrahmanyan: It's a wonderful time to be an astronomer, indeed.

Vera: Thanks for all our listeners out today. We're moving on to the next paper soon!

Jocelyn: Goodbye for now!

Subrahmanyan: See you in the next one!