Chromospheric activity and evolutionary age of the Sun and four solar twins

Abstract

The activity levels of the solar-twin candidates HD 101364 and HD 197027 are measured and compared with the Sun, the known solar twin 18 Sco, and the solar-like star 51 Peg. Furthermore, the absolute ages of these five objects are estimated from their positions in the HR diagram and the evolutionary (relative) age compared with their activity levels. To represent the activity level of these stars, the Mount Wilson S-indices were used. To obtain consistent ages and evolutionary advance on the main sequence, we used evolutionary tracks calculated with the Cambridge Stellar Evolution Code. From our spectroscopic observations of HD 101364 and HD 197027 and based on the established calibration procedures, the respective Mount Wilson S-indices are determined. We find that the chromospheric activity of both stars is comparable with the present activity level of the Sun and that of 18 Sco, at least for the period in consideration. Furthermore, the absolute age of HD 101364, HD 197027, 51 Peg, and 18 Sco are found to be 7.2, 7.1, 6.1, and 5.1 Gyr, respectively. With the exception of 51 Peg, which has a significantly higher metallicity and a mass higher by about 10% than the Sun, the present Sun and its twins compare relatively well in their activity levels, even though the other twins are somewhat older. Even though 51 Peg has a similar age of 6.1 Gyr, this star is significantly less active. Only when we compare it on a relative age scale (which is about 20% shorter for 51 Peg than for the Sun in absolute terms) and use the higher-than-present long-term S${}_{\mathrm{MWO}}$ average of 0.18 for the Sun, does the S-index show a good correlation with evolutionary (relative) age. This shows that in the search for a suitably similar solar twin, the relative main-sequence age matters for obtaining a comparable activity level.

arXiv comment8 pages, 7 figures, accepted for publication in A&A

References in corpus (15)

• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
• Chromospheric CaII Emission in Nearby F, G, K, and M stars
• Chromospheric Activity and Jitter Measurements for 2630 Stars on the California Planet Search
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I
• Structure and Evolution of Nearby Stars with Planets II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog
• Toroidal versus poloidal magnetic fields in Sun-like stars: a rotation threshold
• The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample
• Radius Dependent Angular Momentum Evolution in Low-Mass Stars. I
• The remarkable solar twin HIP 56948: a prime target in the quest for other Earths
• Fluxes in Hαand Ca II H and K for a sample of Southern stars
• Deriving precise parameters for cool solar-type stars. Optimizing the iron line list
• Chromospheric Activities and Kinematics for Solar Type Dwarfs and Subgiants: Analysis of the Activity Distribution and the AVR
• High Precision Abundances of the Old Solar Twin HIP 102152: Insights on Li Depletion from the Oldest Sun
• The Sun-like activity of the solar twin 18 Scorpii

Cited by in corpus (23)

• The Solar Twin Planet Search: The age - chromospheric activity relation
• Evolution of coexisting long and short period stellar activity cycles
• Magnetic Evolution and the Disappearance of Sun-like Activity Cycles
• The Ca II infrared triplet's performance as an activity indicator compared to Ca II H and K
• An X-ray activity cycle on the young solar-like star $\epsilon \mathrm{Eridani}$
• Benchmark ages for the Gaia benchmark stars
• Revisiting the connection between magnetic activity, rotation period, and convective turnover time for main-sequence stars
• Stellar Properties of Active G and K Stars: Exploring the Connection Between Starspots and Chromospheric Activity
• Fifteen years in the high-energy life of the solar-type star HD 81809. XMM-Newton observations of a stellar activity cycle
• Solar chromospheric emission and magnetic structures from plages to intranetwork: Contribution of the very quiet Sun
• Modelling the solar twin 18 Sco
• Magnetic field and chromospheric activity evolution of HD75332: a rapid magnetic cycle in an F star without a hot Jupiter
• Stellar Chromospheric Activity Database of Solar-like Stars Based on the LAMOST Low-Resolution Spectroscopic Survey
• Time evolution of magnetic activity cycles in young suns: The curious case of kappa Ceti
• Coronal X-ray emission and planetary irradiation in HD 209458
• Revisiting the cycle-rotation connection for late-type stars
• Carrington cycle 24: The solar chromospheric emission in a historical and stellar perspective
• Magnetic activity of the solar-like star HD 140538
• The corona -- chromosphere connection studied with simultaneous eROSITA and TIGRE observations
• Correlating Intrinsic Stellar Parameters with Mg II Self-Reversal Depths
• Hunt for Starspots in HARPS Spectra of G and K Stars
• Chromospheric activity and photospheric variation of $\alpha$ Ori during the great dimming event in 2020
• Yet another star in the Albireo system -- The discovery of Albireo Ad