A New Age-Activity Relation For Solar Analogs that Accounts for Metallicity

Author(s)

Carvalho-Silva, Gabriela ; Melendez, Jorge ; Rathsam, Anne ; Shejeelammal, J. ; Martos, Giulia ; Lorenzo-Oliveira, Diego ; Spina, Lorenzo ; Ribeiro Alves, Debora

• Document type: Journal article
• Source: Astrophysical Journal Letters; v. 983, n. 2, p. 7-pg., 2025-04-20.

Abstract

Determining stellar ages is challenging, particularly for cooler main-sequence (MS) stars. Magnetic evolution offers an observational alternative for age estimation via the age-chromospheric activity (AC) relation. We evaluate the impact of metallicity on this relation using near one-solar-mass stars across a wide metallicity range. We analyze a sample of 358 solar-type stars with precise spectroscopic parameters determined through a line-by-line differential technique and with ages derived using Yonsei-Yale isochrones. We measured chromospheric activity (S-index) using high-quality High Accuracy Radial Velocity Planet Searcher spectra, calibrated to the Mount Wilson system and converted to the RHK '(Teff) index with a temperature-based photospheric correction. Our findings show that the AC relation for RHK '(Teff) is strongly influenced by metallicity. We propose a new age-activity-metallicity relation for solar-type MS stars ( logg greater than or similar to 4.2 ) with temperatures 5370 less than or similar to Teff less than or similar to 6530 K and metallicities from -0.7 to +0.3 dex. We show that taking metallicity into account significantly enhances chromospheric ages' reliability, reducing the residuals' rms relative to isochronal ages from 2.6 to 0.92 Gyr. This reflects a considerable improvement in the errors of chromospheric ages, from 53% to 15%. The precision level achieved in this work is also consistent with previous age-activity calibration from our group using solar twins. (AU)

• FAPESP's process: 23/16319-8 - Analysis of stellar activity signals in solar-type stars using Gaussian Processes
• Grantee: Gabriela Carvalho Silva
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• FAPESP's process: 21/01303-3 - Modeling spectroscopic signatures of stellar activity
• Grantee: Gabriela Carvalho Silva
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 22/05833-0 - Planetary chemical signatures in the spectrum of solar twin stars
• Grantee: Giulia Martos
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 22/10325-3 - Precision Spectroscopy of Solar Type Stars
• Grantee: Shejeelammal Jameela
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/04055-8 - High precision spectroscopy: from the first stars to planets
• Grantee: Jorge Luis Melendez Moreno
• Support Opportunities: Research Projects - Thematic Grants