Iota Horologii Is Unlikely to Be an Evaporated Hyades Star

Ramírez, Iván; Yong, David; Gutiérrez, Eduardo Mario; Endl, Michael; Lambert, David L.; Nascimento, J. D. do

doi:10.3847/1538-4357/aa9437

Cited by 2 publications

(1 citation statement)

References 70 publications

(86 reference statements)

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“…𝜄 Horologii (𝜄 Hor, HD 17051, HR 810) is one of the few systems with a robust set of multi-wavelength records covering a period of years (see Baliunas et al 1995;Saar & Osten 1997;Valenti & Fischer 2005;Barnes 2007;Ramírez et al 2017). The star has an estimated age of about ∼ 625 Myr (see Vauclair et al 2008) and similar characteristics to the young Sun (i.e., F8V-G0V, ∼ 6080K, 𝑅 * ∼ 1.16 𝑅 ⊙ Bruntt et al 2010, see Table 1).…”

Section: Introductionmentioning

confidence: 99%

Far beyond the Sun − II. Probing the stellar magnetism of the young Sun ι Horologii from the photosphere to its corona

Amazo-Gómez

Alvarado‐Gómez

Poppenhaeger

et al. 2023

Monthly Notices of the Royal Astronomical Society

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A comprehensive multi-wavelength campaign has been carried out to probe stellar activity and variability in the young Sun-like star ι-Horologii. We present the results from long-term spectropolarimetric monitoring of the system by using the ultra-stable spectropolarimeter/velocimeter HARPS at the ESO 3.6-m telescope. Additionally, we included high-precision photometry from the NASA Transiting Exoplanet Survey Satellite (TESS) and observations in the far- and near-ultraviolet spectral regions using the STIS instrument on the NASA/ESA Hubble Space Telescope (HST). The high-quality dataset allows a robust characterisation of the star’s rotation period, as well as a probe of the variability using a range of spectroscopic and photometric activity proxies. By analyzing the gradient of the power spectra (GPS) in the TESS lightcurves we constrained the faculae-to-spot driver ratio ($\rm S_{fac}/S_{spot}$) to 0.510±0.023, which indicates that the stellar surface is spot dominated during the time of the observations. We compared the photospheric activity properties derived from the GPS method with a magnetic field map of the star derived using Zeeman-Doppler imaging (ZDI) from simultaneous spectropolarimetric data for the first time. Different stellar activity proxies enable a more complete interpretation of the observed variability. For example, we observed enhanced emission in the HST transition line diagnostics C iv and C iii, suggesting a flaring event. From the analysis of TESS data acquired simultaneously with the HST data, we investigate the photometric variability at the precise moment that the emission increased and derive correlations between different observables, probing the star from its photosphere to its corona.

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Section: Introductionmentioning

confidence: 99%

Far beyond the Sun − II. Probing the stellar magnetism of the young Sun ι Horologii from the photosphere to its corona

Amazo-Gómez

Alvarado‐Gómez

Poppenhaeger

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Far-ultraviolet Activity Levels of F, G, K, and M Dwarf Exoplanet Host Stars

Arulanantham

Fossati

Lanza

et al. 2018

ApJS

134

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We present a survey of far-ultraviolet (FUV; 1150 -1450Å) emission line spectra from 71 planethosting and 33 non-planet-hosting F, G, K, and M dwarfs with the goals of characterizing their range of FUV activity levels, calibrating the FUV activity level to the 90 -360Å extreme-ultraviolet (EUV) stellar flux, and investigating the potential for FUV emission lines to probe star-planet interactions (SPIs). We build this emission line sample from a combination of new and archival observations with the Hubble Space Telescope-COS and -STIS instruments, targeting the chromospheric and transition region emission lines of Si III, N V, C II, and Si IV.We find that the exoplanet host stars, on average, display factors of 5 -10 lower UV activity levels compared with the non-planet hosting sample; this is explained by a combination of observational and astrophysical biases in the selection of stars for radial-velocity planet searches. We demonstrate that UV activity-rotation relation in the full F -M star sample is characterized by a power-law decline (with index α ≈ −1.1), starting at rotation periods 3.5 days. Using N V or Si IV spectra and a knowledge of the star's bolometric flux, we present a new analytic relationship to estimate the intrinsic stellar EUV irradiance in the 90 -360Å band with an accuracy of roughly a factor of ≈ 2. Finally, we study the correlation between SPI strength and UV activity in the context of a principal component analysis that controls for the sample biases. We find that SPIs are not a statistically significant contributor to the observed UV activity levels.

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Iota Horologii Is Unlikely to Be an Evaporated Hyades Star

Cited by 2 publications

References 70 publications

Far beyond the Sun − II. Probing the stellar magnetism of the young Sun ι Horologii from the photosphere to its corona

Far beyond the Sun − II. Probing the stellar magnetism of the young Sun ι Horologii from the photosphere to its corona

Far-ultraviolet Activity Levels of F, G, K, and M Dwarf Exoplanet Host Stars

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