Carbon and nitrogen isotopes in the Galaxy’s thin disc based on solar twins and analogues

Abstract

Carbon, nitrogen and oxygen in stars bring valuable information for Galactic chemical evolution (GCE) modelling, stellar evolution and exoplanet studies. We have measured the ¹² C abundance, the isotopic ratio ¹² C/ ¹³ C and the ¹⁴ N abundance for 27 solar analogue stars and 55 solar twin stars, having both samples a wide range in isochrone age. ¹⁴ N and ¹⁴ N/ ¹⁵ N have been measured for 59 metal-rich solar twin stars that have a wide age coverture too. The three samples contain solar-type dwarfs belonging to the Galactic thin disc up to around 106 pc in distance. All samples stars are identified as stars hosting gaseous giant planets and stars without detected gaseous giant planets. Both isotopic ratios have been derived for ‘solar twins’ for the first time. In this work, we compile our main results on several abundance ratios involving C and N isotopes as a function of the isochrone age and metallicity.