Lmst

New in the #VirtualObservatory: “Low-luminosity Kepler red giants analysis” by Kuszlewicz J.S. et al.
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/954/152
#ChemicalAbundances #StellarMasses #GiantStars #Asteroseismology

New in the #VirtualObservatory: “Improved stellar parameters of Kepler RGB stars” by Wang Y. et al.
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/953/182
#Asteroseismology #GiantStars #ChemicalAbundances #StellarAges

Glad to see a descendent of another stellar evolution code that I once used putting out a fresh instrument paper (of a series to be?):

https://arxiv.org/abs/2511.02801

I've always found Cesam2k20 particularly interesting because I think it has the most advanced treatment (among 1D codes) of rotation, and because it possibly uniquely uses a collocation method to solve the spatial equations.

Find out more about the code at their website:

https://www.ias.u-psud.fr/cesam2k20/

#astronomy #asteroseismology

For #asteroseismology, Kepler's sensitivity and observing duration is unparalleled. TESS has been exciting for otherwise-interesting bright stars but I've felt K2 was neglected. The 90d baseline is valuable but the systematics gnarly. So I'm delighted to see Hookway et al.'s (2025) analysis of solar-like oscillators in the K2 "KEYSTONE" sample.

https://arxiv.org/abs/2510.21626

Here's an example power spectrum for a late subgiant, where the symbols indicate individual oscillation modes. 🤩

#astronomy

Power spectrum for the late subgiant EPIC 236224056, using data observed by the K2 mission. There is a clear comb of individual peaks with frequencies between 600 and 900 microhertz, in which each peak corresponds to a resonant oscillation mode. A best-fit model is superimposed, along with symbols indicating the angular degree of the detected oscillation modes.

New in the #VirtualObservatory: “Beyond the Nyquist frequency” by Liagre B. et al.
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/702/A144
#Asteroseismology #GiantStars #ChemicalAbundances #VisibleAstronomy

It's still #TESStuesday! And today's there's some neat #asteroseismology.

You may have heard of the "Methusaleh star", which is very old but I honestly don't think was ever a challenge to the accepted age of the Universe. But this study of the oscillations based on TESS data is nevertheless interesting because it's very poor in metals relative to other asteroseismic targets, and shows that our rough rules for oscillation properties seem to deviate at low metallicity.

https://arxiv.org/abs/2510.11532

Figure 2 of Lundkvist and collaborators' study of the very old, very metal-poor star HD 140283, known as the Methusaleh star. The diagram shows HD 140283 relative to other observations in terms of the frequency of maximum oscillation power or "nu max" and the overall metallicity. HD 140283 stands out for being the most metal poor star with a nu max above about 500 microhertz.

New in the #VirtualObservatory: “TESS Luminaries Sample. I.” by Lund M. N. et al.
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/701/A285
#DwarfStars #Asteroseismology #GStars #SpectroscopicBinaryStars

I might incur 13.7 days of bad luck for sharing a non-TESS light curve on #TESStuesday but this multi-band light curve from the brand new Vera C. Rubin Observatory's commissioning data is too good. 🤩

This is a distant (16.6kpc), faint (18th magnitude) SX Phe variable but the light curve has the unmistakable shape (in the optical g band) of a δ Sct/SX Phe variable.

https://iopscience.iop.org/article/10.3847/2515-5172/adeab0

#astronomy #astrodon #asteroseismology

Multi band light curve of a distant SX Phoenicis variable star described by Carlin et al. in a recent RNAAS article, using data from the recently-commissioned Vera C. Rubin Observatory. There are phase-folded light curves in the g, i, r and z bands, with the g band light curve showing the characteristic sawtooth shape of many classical pulsators.

NASA's TESS satellite serendipitously observed the 2019 eclipse of γ Per and I'm delighted to see it got some attention in a poster by László Molnár, Rozália Ádám and collaborators at this year's KASC15/TASC8 conference (basically the biggest annual #asteroseismology conference):

https://zenodo.org/records/13641744

#astronomy

(The imaged light curve is my own but in essence the same as one in the poster.)

A light curve of Gamma Persei from NASA's TESS space telescope, clearly showing a roughly two-week-long eclipse.

This #TESStuesday, I offer the eclipsing binary TY Pyx. Nothing at all made me think "I don't think I've ever looked at variables in Pyxis", so I grabbed something at random from the GCVS. So here it is, with very spotty out-of-eclipse variations also make it an RS CVn variable. Spectral type is G5IV+G5IV so I tried my hand at finding solar-like oscillations but I didn't find anything (though I didn't try *that* hard).

#asteroseismology

A section of the TESS light curve of the eclipsing binary TY Pyxidis, which is also an RS CVn variable. The eclipses are clear, with a period of about 3.2 days, as are the slower out-of-eclipse variations caused by starpots.

A section of the TESS light curve of the eclipsing binary TY Pyxidis, which is also an RS CVn variable, with the vertical axis limited to about magnitude 6.2 to 6.24 to highlight the variations caused by starspots.

I just learned that a recording of this year's Crafoord Prize Symposium in #Astronomy, which happened on Wednesday, is available online. This year's laureates are Douglas Gough, Jørgen Christensen-Dalsgaard (aka JCD) and Conny Aerts, for developing helio- and #asteroseismology.

https://www.youtube.com/watch?v=HMwMsHj0K1U

You can find the programme here:

https://www.kva.se/en/event/the-crafoord-prize-symposium-in-astronomy-2024-2/

Big thanks to the Royal Swedish Academy of Sciences for making this available so promptly!

New in the #VirtualObservatory: “Asteroseismically calibrated ages for APOGEE DR17” by Boulet T.
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/685/A66
#GiantStars #StellarAges #MilkyWayGalaxy #Asteroseismology

For #TESStuesday, I recently came across Tobin et al.'s discovery of a substellar companion around the γ Dor variable HIP 39017 (= V769 Mon). The TESS light curve (some of Sector 7 shown) does *not* disappoint.

https://arxiv.org/abs/2403.04000

#asteroseismology

Light curve of the Gamma Doradus type variable V769 Monocerotis, as observed by TESS during its Sector 7. There are clear pulsations with a period of about 0.6 days and an amplitude that varies between 0.07 and 0.01 magnitudes.

In Nature yesterday:

"Smallest known starquakes are detected with a subtle shift of colour: An unusual technique picks up the slow vibration of a faint star."

"Unusual"? I guess in a very specific sense it's not wrong to call a radial-velocity detection of solar-like oscillations "unusual" but I feel like it betrays that RVs are

(a) how we measure solar oscillations and
(b) how solar-like oscillations were first detected.

#astronomy #asteroseismology

https://www.nature.com/articles/d41586-024-00965-1

Advancements in Asteroseismology Explain Red Clump Stars' Pulsations https://researchinenglish.com/article/2024.3/advancements-in-asteroseismology-explain-red-clump-mfgpjotl?utm_source=mastodon&utm_medium=social

#astrophysics #science #research #modelling #stars #asteroseismology

For #TESStuesday, I bring the rapidly-oscillating peculiar A (roAp) star γ Equ, whose pulsations I didn't know about until I saw this paper by Järvinen et al. in which they study the magnetic splitting (Zeeman effect) in its spectrum.

The TESS amplitude spectrum (data in Sector 55) is a textbook roAp star, with a strong peak at a period of ~116 c/d = a period of ~12.5 minutes.

https://arxiv.org/abs/2401.16966

#asteroseismology

Segment of the amplitude spectrum of the rapidly-oscillating AP type star Gamma Equuleus using TESS data, showing a strong peak around 116 cycles per day and amplitude of about 0.3 millimagnitudes.

I only learned today that Wasaburo Unno died two months ago (Nov 7, 2023). Apparently he's best known for a formula (the Unno—Rachkovsky formula) for deriving magnetic field strengths from polarimetry, but I expect everyone in #helioseismology or #asteroseismology will know him for his famous textbooks on non-radial stellar pulsations.

You can learn more about him from his obituary in Solar Physics:

https://link.springer.com/article/10.1007/s11207-023-02238-y

#TESStuesday is not forgotten! On arXiv today, Sepulveda et al. show amplitude spectra from TESS of the definitely-δ-Sct-variable HIP 65426 (HD 116434), whose orbiting planet was the to be imaged by JWST (Carter et al., 2023). It rotates crazy fast (jargon, sorry): vsini ≈ 280 km/s, rotation period ~7.3h so the echelle diagram lacks any patterns that we recognise (yet?).

https://arxiv.org/abs/2312.05310

#asteroseismology #astronomy

Amplitude spectrum of the star HIP 65426 using observations by NASA's TESS observatory. There are multiple sharp peaks with periods between about 20 and 90 cycles per day, which means the star is a δ Scuti variable.

Just uploaded the "asteroseismic" HR diagram I created for my review in A&G to the Wikimedia Commons and added it to the @wikipedia article on #Asteroseismology. Use it and edit it to suit your needs!

#astronomy #astrodon

It's also taught me that SVG is a bit of a weird format. I can't paste it here and there are a few flaws in the online preview version that I can't reproduce...

https://commons.wikimedia.org/wiki/File:Asteroseismic_HR_diagram.svg

Just missed another #TESStuesday but here are the clear solar-like oscillations in β Hyi anyway, using 20-second data from TESS Sector 67. TESS's PI recently spoke at a conference in Hawai'i and revealed that the spacecraft—already 5 years into its mission—could last *decades*...

#asteroseismology

#Asteroseismology

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