The effect of stellar activity on the spectroscopic stellar parameters of the young solar twin HIP 36515

Author(s)

Galarza, Jhon Yana ^[1] ; Melendez, Jorge ^[1] ; Lorenzo-Oliveira, Diego ^[1] ; Valio, Adriana ^[2] ; Reggiani, Henrique ^[1] ; Carlos, Marilia ^[1] ; Ponte, Geisa ^{[3, 2]} ; Spina, Lorenzo ^[4] ; Haywood, Raphaelle D. ^[5] ; Gandolfi, Davide ^[6]

Affiliation

^[1] Univ Sao Paulo, Dept Astron IAG USP, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil

^[2] Univ Prebiteriana Mackenzie, CRAAM, Rua Consolacao 896, BR-01301000 Sao Paulo - Brazil

^[3] Univ Fed Rio de Janeiro, Observ Valongo, Ladeira Pedro Antonio 43, BR-20080090 Rio De Janeiro, RJ - Brazil

^[4] Monash Univ, Monash Ctr Astrophys, Sch Phys & Astron, Clayton, Vic 3800 - Australia

^[5] Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 - USA

^[6] Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin - Italy

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 490, n. 1, p. L86-L90, NOV 2019.
• Web of Science Citations: 0

Abstract

Spectroscopic equilibrium allows us to obtain precise stellar parameters in Sun-like stars. It relies on the assumption of the iron excitation and ionization equilibrium. However, several works suggest that magnetic activity may affect chemical abundances of young active stars, calling into question the validity of this widely used method. We have tested, for the first time, variations in stellar parameters and chemical abundances for the young solar twin HIP 36515 (similar to 0.4 Gyr), along its activity cycle. This star has stellar parameters very well established in the literature and we estimated its activity cycle in similar to 6 yr. Using HARPS spectra with high resolving power (115 000) and signal-to-noise ratio (similar to 270), the stellar parameters of six different epochs in the cycle were estimated. We found that the stellar activity is strongly correlated with the effective temperature, metallicity, and microturbulence velocity. The possibility of changes in the Li I 6707.8 angstrom line due to flares and star-spots was also investigated. Although the core of the line profile shows some variations with the stellar cycle, it is compensated by changes in the effective temperature, resulting in a non-variation of the Li abundance. (AU)

• FAPESP's process: 16/20667-8 - Stellar chronometers: the relation between age, chromospheric activity, rotation and lithium abundances in solar-type stars
• Grantee: Diego Lorenzo de Oliveira
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 18/04055-8 - High precision spectroscopy: from the first stars to planets
• Grantee: Jorge Luis Melendez Moreno
• Support type: Research Projects - Thematic Grants