StarXiv: a podcast discussing the latest astronomy papers · Michelle and Payel

Episode 28 - Fading stars, digesting planets and dark matter conundrums

·33 min·1 clip

Six and a half years of data proves Betelgeuse's hidden companion: a star hiding inside a star

This episode of StarXiv features hosts Michelle and Pyle discussing recent astronomy papers after a hiatus due to teaching and injuries. They cover four distinct research topics, starting with two studies on variable red supergiant stars. Andrea K. Dupree and colleagues used six and a half years of spectral data from HERMES and TRES instruments to detect a wake in Betelgeuse's circumstellar disc, supporting the existence of a low-mass companion star named SuWaha orbiting every 2,109 days. Jacob van Loon and Keiichi Onaka analyzed WO HG 64, an extreme red supergiant in the Large Magellanic Cloud that dramatically dimmed in the 2020s, attributing its behavior to a binary interaction with a hotter component tightening the Roche lobe. Simona Vegetti's team studied the gravitational lensing system J+666, finding a thin arc likely caused by a dark subhalo with a density profile challenging for standard cold or warm dark matter models, possibly indicating self-interacting dark matter. Caitlin Lane's simulations show stars between 1 and 1.4 solar masses are ideal for detecting chemical pollution from engulfed rocky planets, with engulfment timescales ranging from a few years to thousands. Alexander Roman's paper employs autoencoder machine learning on 69,000 synthetic exoplanet spectra to efficiently identify atmospheres anomalous in CO₂, finding k-means clustering in latent space most robust against noise. The hosts highlight how both stellar studies involve observable changes on human timescales, contrasting typical astronomy. They note the dark matter subhalo's inferred density is 10-20 sigma away from standard predictions, similar to anomalies found in stellar stream studies. The planet-engulfment research reveals aluminum, calcium, vanadium, and lithium as key detectable pollutants. The machine learning method is framed as crucial for upcoming missions like ESA's ARIEL. The conversation is casual and educational, filled with personal asides and collaborative excitement. Listeners interested in stellar evolution, exoplanet detection methods, or dark matter puzzles will enjoy this episode, while those seeking highly produced narratives might find the academic focus less engaging.

As heard by us

A technical astronomy discussion that stays curious and methodical while working through a dark-matter lensing puzzle.

StarCive opens with the hosts back together after a while apart, then settles into a paper about how to probe a dark object with no stars attached.

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Why you'd press play

Press play if you want a lensing puzzle about a second arc and a possible dark perturber.

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