ORIGIN AND PROPERTIES OF NARROW CAII AND NAI ABSORPTION LINES ON HD 039060 SPECTRUM

• Main Author: Rizky Syandana, Radithya
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85562
• Institution: Institut Teknologi Bandung

Stellar spectrum not only reveals informations of the star, but also diffuse matters in between the star and the observer. These diffuse matters can be in the form of interstellar or circumstellar matters. HD 039060, also known as ? Pictoris, is a close A6 V class star at 19.44 pc from the Sun. Stars at that distance is expected to not have strong interstellar absorption because it is inside the local bubble. However, HD 039060 shows the a pretty strong narrow absorption lines, mainly NaI doublet D1 and D2 and CaII doublet H and K lines. This final project aims to determine the source of those narrow lines which could originate from interstellar or circumstellar source, and also determine the physical properties of the source. The methods used in this final project are spectral analysis of HD 039060 spectrum (absorption lines measurement and matching) and its comparison with nearby stars. From literature studies and comparison with nearby stars, it is found that the narrow NaI D1 and D2 and CaII H and K lines of the HD 039060 spectrum originate from circumstellar matter. On NaI region, the narrow absorption lines shows radial velocity of 18.03 km/s, whereas on CaII region, two lines of different velocity groups are found, the stationary line at 19.1 km/s and the variable line at 28.6 km/s. The stationary line originate from evaporating dust in the stellar disk, whereas the variable line is thought to be from a star-grazing falling-evaporating bodies (FEB). The measurement result shows that the source of the narrow NaI D2 line has temperature of around 1714.45 K and column density of 5.06 × 1010 cm?2. The stationary CaII line has temperature of 8333.9 K and column density of 2.46 × 1015 cm?2, whereas the variable line has temperature of 6136.25 K and column density of 7.61 × 1011 cm?2.