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arxiv: 2604.00498 · v2 · submitted 2026-04-01 · 🌌 astro-ph.SR · physics.data-an

Recognition: no theorem link

Global asteroseismology of 19,000 red giants in the TESS Continuous Viewing Zones

K. R. Sreenivas , Timothy R. Bedding , Daniel Huber , Dennis Stello , Marc Hon , Claudia Reyes , Yaguang Li , Daniel Hey
Authors on Pith no claims yet

Pith reviewed 2026-05-13 22:25 UTC · model grok-4.3

classification 🌌 astro-ph.SR physics.data-an
keywords asteroseismologyred giantsTESSstellar masses and radiigalactic archaeologyRGB bumpasteroseismic catalogue
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The pith

Asteroseismology of 19,000 TESS red giants delivers mass and radius precisions matching Kepler data

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper compiles an asteroseismic catalogue for 19,151 red giant stars observed by TESS in its continuous viewing zones over seven years. The authors extract key oscillation parameters from the power spectra and classify the stars into red-giant-branch and core-helium-burning stages. For the 10,298 stars that also have spectroscopic data, they derive masses and radii at 7.5 percent and 2.8 percent precision, respectively. These values are comparable to those obtained from four years of Kepler observations, and the parameters also reveal the red-giant-branch bump and zero-age helium-burning edge while tracing trends across the Galactic plane.

Core claim

The paper establishes a catalogue of asteroseismic parameters for 19,151 red giants, including the frequency of maximum power and the large frequency separation, derived from TESS photometry. Using a convolutional neural network for evolutionary classification and combining the results with spectroscopic data, it measures stellar masses and radii with 7.5 percent and 2.8 percent precision for 10,298 stars. The measurements match the precision achieved with four-year Kepler data, show excellent agreement with Gaia radii, and enable identification of the RGB bump and zero-age helium-burning edge with only three years of TESS observations.

What carries the argument

The pySYD pipeline that extracts nu_max and Delta nu from the power spectra, after visual assessment and nuSYD confirmation of oscillations

If this is right

  • Stellar masses and radii can be determined uniformly for a large galactic sample suitable for archaeology studies.
  • Three years of TESS data suffice to identify the red-giant-branch bump and delineate the zero-age helium-burning edge.
  • Seismic radii agree with Gaia radii, confirming the reliability of the asteroseismic scale.
  • The parameters reveal established trends in stellar properties across the Galactic plane when combined with astrometry.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same extraction methods could be extended to additional TESS sectors to increase the sample size beyond the continuous viewing zones.
  • The catalogue supplies a ready test set for calibrating stellar-evolution models that predict the locations of the RGB bump and helium-burning edge.
  • When cross-matched with exoplanet-host catalogues, the precise masses and radii could improve constraints on planet occurrence rates around evolved stars.

Load-bearing premise

The assumption that visual assessment combined with nuSYD confirmation and pySYD extraction reliably identifies true oscillations and yields unbiased parameters for TESS data quality and sampling.

What would settle it

A systematic discrepancy larger than the stated uncertainties between the derived seismic radii and independent Gaia radius measurements across the 10,298-star spectroscopic subsample.

Figures

Figures reproduced from arXiv: 2604.00498 by Claudia Reyes, Daniel Hey, Daniel Huber, Dennis Stello, K. R. Sreenivas, Marc Hon, Timothy R. Bedding, Yaguang Li.

Figure 1
Figure 1. Figure 1: Colour-magnitude diagram using Gaia apparent magnitudes of all stars in TESS CVZ with TESS magnitude brighter than 13.5. The rectangle shows the 72,647 stars selected for analysis in this work. of asteroseismic measurements, these datasets enabled studies of the solar neighbourhood and the mapping of our Galaxy (Miglio et al. 2012; Anders et al. 2017; Zinn et al. 2022; Pinsonneault et al. 2025). While prev… view at source ↗
Figure 2
Figure 2. Figure 2: Solar like oscillations of a typical red giant. Panel a shows the power density spectra of an oscillating Kepler red giant (KIC 9075872, 𝐾𝑝 = 11.89 ) and Panel b for an oscillating red giant (TIC 237197414, Tmag = 7.084) in the northern TESS CVZ. Disposition = NULL columns in the TIC. The first criterion en￾sures that the stars have reliable astrometric information from Gaia (Arenou et al. 2018), and the s… view at source ↗
Figure 3
Figure 3. Figure 3: Gaia Absolute Magnitude (𝑀𝐺) vs Frequency of Maximum power (𝜈max) for all 16,094 Kepler stars in Yu et al. (2018). The red line corresponds to the fit provided in eqn. 1. cadence of 30 minutes, which was later reduced to 10 min (Year 3 onwards) and then to 200 seconds (Year 5 onwards). Two of the widely used light curve products from these FFIs are TESS-SPOC (Jenkins et al. 2016; Caldwell et al. 2020) and … view at source ↗
Figure 4
Figure 4. Figure 4: Frequency of Maximum power vs TESS Magnitude for all 17,617 stars in the sample. Top panel shows the stars colour coded by their detection probability. The bottom panel shows stars which were visually verified (black). The red points are the detections and the dashed line shows the empirical detection limit from (Hon et al. 2021). 72,647 stars in logarithmic space and classified the detection of oscil￾lati… view at source ↗
Figure 5
Figure 5. Figure 5 [PITH_FULL_IMAGE:figures/full_fig_p004_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Distribution of stellar spectroscopic parameters from (Yu et al. 2023) for our sample, red for 7469 RGB and blue for 2723 CHeB stars. Panel a shows the effective temperature, panel b shows the metallicity and panel c shows log 𝑔. To verify the quality of the Δ𝜈 measurements, we used the neu￾ral network developed by Reyes et al. (2022). The network uses 𝜈max, Δ𝜈 and the background-corrected power density sp… view at source ↗
Figure 7
Figure 7. Figure 7: Distribution of Mass (top panel), Radius (middle panel) and log g (bottom panel) for the 10,298 stars which has reliable measurement of Δ𝜈. The insets show the uncertainty in stellar parameters. The red histograms show the distribution of uncorrected mass and radii. The dashed vertical lines show the median values of the distributions. 3.4 Determination of evolutionary states Based on their core properties… view at source ↗
Figure 8
Figure 8. Figure 8: Properties of the stars in our final sample. The top two diagrams show the distribution of 17,617 oscillating red giants in northern CVZ and southern CVZ. Panel a shows the distribution of TESS magnitude, panel b shows the distribution of 𝜈max, panel c shows the fractional uncertainty on 𝜈max and panel d shows the fractional uncertainty on Δ𝜈. The histograms in black corresponds to the full sample of red g… view at source ↗
Figure 9
Figure 9. Figure 9: Comparison of asteroseismic radii with spectroscopic parameters, for the stars in gold sample. Panel a shows the comparison of GAIA radii for RGB stars and panel b shows the comparison for CHeB stars, both colour-coded by 𝜈max. The blue and orange lines show the median offset between asteroseismic radii determined using asfgrid (Sharma et al. 2016) corrections with Gaia radii for RGB and CHeB stars, respec… view at source ↗
Figure 11
Figure 11. Figure 11: Comparison of the RGB bump and the red clump between Kepler, K2 and TESS. The top panel shows the mass–radius plots of the RGB stars and the bottom panel is for CHeB stars. The green shaded region is an arbitrarily chosen region to guide the eye for locating approximate locations of RGB bump and CHeB clump. section, we assess whether our TESS CVZ data reveal similar fea￾tures and compare them with Kepler … view at source ↗
Figure 10
Figure 10. Figure 10: Comparison of asteroseismic and stellar parameters with measure￾ments from previous studies. Red points corresponds to values from Zhou et al. (2024), olive points from Mackereth et al. (2021) and cyan points from Hon et al. (2022). Panel a shows the comparison of 𝜈max values and panel b shows the comparison of Δ𝜈 values. panel c and d represents mass and radius, respectively. The fractional difference is… view at source ↗
Figure 12
Figure 12. Figure 12: Kiel diagram of the 5226 stars in gold sample. The x-axis represents the effective temperature, while the y-axis corresponds to log 𝑔. Panel a illustrates the asteroseismic log 𝑔 as blue points and the spectroscopic log 𝑔 as grey points for 4061 RGB stars. Panel b displays the Kiel diagram for 1165 CHeB stars, represented in orange. Panels c and d show the Kiel diagram for all stars, colour-coded by metal… view at source ↗
Figure 13
Figure 13. Figure 13: Analysis of the gold sample in Galactocentric coordinates. Panel a shows the positional distribution of all the oscillating stars, colour-coded by mass. The solid lines show the median 𝑧 per bin and error bars show the median absolute deviation (MAD). Panel b shows the Toomre diagram colour-coded by mass. The dashed semicircles show the boundaries from Mardini et al. (2022) used to delineate different pop… view at source ↗
Figure 14
Figure 14. Figure 14: Projection of stars with asteroseismic ages from various space missions in Galactocentric coordinates. The top panel shows the vertical height from the plane as a function of distance from the Galactic centre, which is denoted using a cross symbol. The bottom panel shows the distribution as viewed towards galactic centre. The orange points are Kepler data from Pinsonneault et al. (2025), green points for … view at source ↗
read the original abstract

TESS (Transiting Exoplanet Survey Satellite) has produced long-term photometry for millions of stars across the sky. In this work, we present an asteroseismic catalogue of 19,151 red giants in the TESS Continuous Viewing Zones using sectors 1--87 (Years 1--7). We visually assessed the power spectra for oscillations, and then applied the computationally efficient nuSYD method to confirm reliability. We identified an increase of 80% in the number of previously known oscillating red giants at a TESS magnitude $>$ 8. We determined the frequency of maximum power ($\rm \nu_{max}$) and the large frequency separation ($\rm \Delta \nu$) using the pySYD pipeline, achieving typical precisions of 1.5% and 1%, respectively. We classified the stars into Red Giant Branch (RGB) and Core Helium Burning (CHeB) classes using a Convolutional Neural Network. Using spectroscopic data for 10,298 stars with reliable asteroseismic measurements, we have been able to measure stellar mass and radii with precisions of 7.5% and 2.8%, which is comparable to that from 4-yr $Kepler$ data. A comparison of the seismic radii with Gaia radii shows excellent agreement. With three years of TESS data, the asteroseismic parameters are precise enough to identify the RGB bump and delineate the Zero Age Helium Burning edge. Combined with astrometric data, these parameters reveal established trends across the Galactic plane, providing a valuable set of uniformly determined asteroseismic parameters for Galactic Archaeology.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper reports an asteroseismic catalogue of 19,151 red giants in the TESS Continuous Viewing Zones (sectors 1-87), obtained by visual inspection of power spectra followed by confirmation with the nuSYD pipeline and parameter extraction (nu_max and Delta nu) via pySYD. For the subset of 10,298 stars with spectroscopic data, stellar masses and radii are derived with claimed precisions of 7.5% and 2.8% using standard scaling relations; these are stated to be comparable to 4-year Kepler results. The stars are classified into RGB and CHeB evolutionary states with a convolutional neural network. The catalogue shows good agreement between seismic and Gaia radii, recovers known features such as the RGB bump, and is positioned for use in Galactic archaeology.

Significance. If the internal precisions and lack of bias hold, the work delivers a large, uniformly processed sample of asteroseismic parameters for red giants across a wide magnitude range and new sky coverage, substantially expanding the dataset available for Galactic archaeology. The reported ability to detect the RGB bump and ZAHB edge with only three years of TESS data, together with the Gaia radius agreement, indicates practical utility for population studies.

major comments (2)
  1. [Methods (pySYD application and precision reporting)] Methods (oscillation detection and pySYD extraction): The central precision claims (1.5% on nu_max, 1% on Delta nu, leading to 7.5%/2.8% mass/radius) rest on the assumption that the visual + nuSYD + pySYD chain yields unbiased parameters for TESS sampling, duty cycle, and noise properties. No injection-recovery statistics or cross-pipeline comparisons specific to TESS CVZ light curves are described, so it is unclear whether the formal precisions are realistic rather than optimistic.
  2. [Results (seismic parameters and Gaia comparison)] Results (mass/radius precision and Gaia comparison): While the Gaia radius agreement provides an external check on radii, it does not validate the mass precision or the full error budget for the 10,298 stars. Additional tests (e.g., consistency with independent mass indicators or period-spacing constraints) would be needed to support the claim that the mass precision is truly comparable to Kepler.
minor comments (2)
  1. [Abstract] Abstract: the statement of an 80% increase in known oscillating red giants at TESS mag >8 would benefit from stating the absolute previous and new counts for immediate context.
  2. [Evolutionary classification] The CNN classification section should report the training/validation accuracy and any confusion matrix to allow assessment of RGB/CHeB purity.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive and positive review. The comments highlight important aspects of validation that we address point-by-point below. We believe the suggested clarifications will strengthen the manuscript without altering its core conclusions.

read point-by-point responses

  1. Referee: Methods (oscillation detection and pySYD extraction): The central precision claims (1.5% on nu_max, 1% on Delta nu, leading to 7.5%/2.8% mass/radius) rest on the assumption that the visual + nuSYD + pySYD chain yields unbiased parameters for TESS sampling, duty cycle, and noise properties. No injection-recovery statistics or cross-pipeline comparisons specific to TESS CVZ light curves are described, so it is unclear whether the formal precisions are realistic rather than optimistic.

    Authors: We appreciate this observation. The quoted precisions are the median formal uncertainties from pySYD fits after visual confirmation with nuSYD. pySYD has been benchmarked on both Kepler and TESS data in its original publications and subsequent works, showing good recovery of input parameters in simulated spectra. Our visual inspection step further filters for reliable detections across the TESS CVZ duty cycle and noise levels. We agree that TESS-specific injection-recovery tests would provide additional reassurance. We will expand the methods section to include a dedicated paragraph on pipeline validation, citing relevant prior tests on TESS light curves, and explicitly note that the reported values are formal uncertainties. This constitutes a partial revision as we cannot add new simulations here but can clarify the existing basis. revision: partial

  2. Referee: Results (mass/radius precision and Gaia comparison): While the Gaia radius agreement provides an external check on radii, it does not validate the mass precision or the full error budget for the 10,298 stars. Additional tests (e.g., consistency with independent mass indicators or period-spacing constraints) would be needed to support the claim that the mass precision is truly comparable to Kepler.

    Authors: We agree that the Gaia radius comparison primarily validates the radii derived from the scaling relations. Masses depend on the combination of nu_max, Delta nu, and spectroscopic parameters, so the Gaia check does not independently constrain the mass error budget. The statement of comparability to 4-year Kepler results refers to the similar median formal precisions achieved with the same scaling relations in the Kepler literature. To strengthen this, we will revise the relevant results section to (i) explicitly state that mass precisions are formal, (ii) add a brief comparison to APOGEE-derived masses for the overlapping subset where available, and (iii) qualify the Kepler comparison as referring to reported formal uncertainties rather than a full end-to-end validation. This will be incorporated in the revised manuscript. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation relies on external pipelines and standard scaling relations

full rationale

The paper extracts nu_max and Delta nu via the established pySYD pipeline (after visual assessment and nuSYD confirmation) and applies standard asteroseismic scaling relations to spectroscopic data for mass and radius. These steps use independently developed tools and literature scaling relations whose validity is external to the present work; reported precisions follow from formal error propagation rather than any self-referential fit or redefinition. Gaia radius comparisons supply external checks, and no equation or claim reduces by construction to the inputs being reported. The central results are therefore self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central results rest on standard asteroseismic scaling relations and established analysis pipelines without new free parameters or invented entities introduced in the abstract.

axioms (1)
  • domain assumption Asteroseismic scaling relations connect nu_max and Delta nu to stellar mass and radius with known accuracy for red giants
    Invoked to derive masses and radii from the measured frequencies for stars with spectroscopy.

pith-pipeline@v0.9.0 · 5624 in / 1258 out tokens · 49075 ms · 2026-05-13T22:25:16.503558+00:00 · methodology

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Reference graph

Works this paper leans on

1 extracted references · 1 canonical work pages

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