An Introduction to Data Analysis in Asteroseismology

Campante, Tiago L.

doi:10.1007/978-3-319-59315-9_3

Cited by 4 publications

(1 citation statement)

References 41 publications

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“…To test the significance of the detection and measure ν max and ∆ν we used 15 independent analysis methods within working group 1 of the TESS Asteroseismic Science Consortium (e.g. Huber et al 2009;Mathur et al 2010;Mosser et al 2012;Benomar et al 2012;Kallinger et al 2012;Corsaro & De Ridder 2014;Davies & Miglio 2016;Campante 2018). All but one pipeline reported a significant detection of solar-like oscillations.…”

Section: Global Asteroseismic Parametersmentioning

confidence: 99%

TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star

Addison

Wright

Nicholson

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA’s Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the Minerva-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of MP = 0.138 ± 0.023 $\rm {M_J}$ (43.9 ± 7.3 M⊕), a radius of RP = 0.639 ± 0.013 $\rm {R_J}$ (7.16 ± 0.15 R⊕), bulk density of $0.65^{+0.12}_{-0.11}$ (cgs), and period $18.38818^{+0.00085}_{-0.00084}$ $\rm {days}$. TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M* = 1.390 ± 0.046 $\rm {M_{sun}}$, R* = 1.888 ± 0.033 $\rm {R_{sun}}$, Teff = 6075 ± 90 $\rm {K}$, and vsin i = 11.3 ± 0.5 km s−1. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a ∼71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (∼100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems.

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Section: Global Asteroseismic Parametersmentioning

confidence: 99%

TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star

Addison

Wright

Nicholson

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The subgiant HR 7322 as an asteroseismic benchmark star

Stokholm

Nissen

Aguirre

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present an in-depth analysis of the bright subgiant HR 7322 (KIC 10005473) using Kepler short-cadence photometry, optical interferometry from CHARA, high-resolution spectra from SONG, and stellar modelling using grids and the Bayesian grid-fitting algorithm . HR 7322 is only the second subgiant with high-quality Kepler asteroseismology for which we also have interferometric data. We find a limb-darkened angular diameter of 0.443 ± 0.007 mas, which, combined with a distance derived using the parallax from Gaia DR2 and a bolometric flux, yields a linear radius of 2.00 ± 0.03 R and an effective temperature of 6350 ± 90 K. HR 7322 exhibits solar-like oscillations, and using the asteroseismic scaling relations and revisions thereof, we find good agreement between asteroseismic and interferometric stellar radius. The level of precision reached by the careful modelling is to a great extent due to the presence of an avoided crossing in the dipole oscillation mode pattern of HR 7322. We find that the standard models predict a stellar radius systematically smaller than the observed interferometric one and that a sub-solar mixing length parameter is needed to achieve a good fit to individual oscillation frequencies, interferometric temperature, and spectroscopic metallicity.

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A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS

Huber

Chaplin

Chontos

et al. 2019

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We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V=8.2 mag), spectroscopically classified subgiant that oscillates with an average frequency of about 430 μHz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2 minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (R å =2.943±0.064 R e), mass (M å =1.212±0.074 M e), and age (4.9±1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a "hot Saturn" (R p =9.17±0.33 R ⊕) with an orbital period of ∼14.3 days, irradiance of F=343±24 F ⊕ , and moderate mass (M p =60.5±5.7 M ⊕) and density (ρ p =0.431±0.062 g cm −3). The properties of HD 221416 b show that the host-star metallicity-planet mass correlation found in sub-Saturns (4-8 R ⊕) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to ∼15%, HD 221416 b is one of the best characterized Saturn-size planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology.

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An Introduction to Data Analysis in Asteroseismology

Cited by 4 publications

References 41 publications

TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star

TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star

The subgiant HR 7322 as an asteroseismic benchmark star

A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS

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