Extragalactic 85Rb/87Rb and 6Li/7Li ratios in the Small Magellanic Cloud

Understand

The line of sight toward Sk 143 (AzV 456), an O9.5 Ib star in the Small Magellanic Cloud (SMC), shows significant absorption from neutral atoms and molecules.

• We report a new study of this line of sight by means of high-resolution spectra obtained with the ESPRESSO spectrograph at the VLT of ESO.
• The absorption from neutral and ionized species is well characterized by a single component at vhel about +132 km/s that was modeled with the ASTROCOOK code.
• The rubidium Rb I 780.0 nm line is detected for the first time outside the Galaxy, and we derive [Rb/H]= -1.86 +/- 0.09.