THE ANALYSIS OF ? LYR SYSTEM: FROM SPECTROSCOPIC OBSERVATION AND STELLAR EVOLUTION SIMULATION
Beta Lyrae (? Lyr) system, two brigthest stars in the Lyra constellation, is a double star system with B-type star and has emission lines in its spectrum so it is also classified as B-emission (Be) type star. The orbital inclination of ? Lyr system is 86° with current orbital period of about 12.9...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/38541 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Beta Lyrae (? Lyr) system, two brigthest stars in the Lyra constellation, is a
double star system with B-type star and has emission lines in its spectrum so it is
also classified as B-emission (Be) type star. The orbital inclination of ? Lyr
system is 86° with current orbital period of about 12.9 days with an additional
orbital period of 19 seconds/year. The mass of the primary component of the
system is 2.88M? with a radius of 14.7R? and an effective temperature of 13,000
K, with a spectrum class B6-B8II. The secondary component has a mass of about
12.97M? with a radius of 6.1R? and an effective temperature of 27.989 K, as a
spectrum class of B0.5V. Because the mass of the primary component is smaller
than the secondary component, ? Lyr is also categorized as the Algol star system.
This research is focused on two methods. The first method is the implementation
of observation. Observations were conducted from May to August 2018, at the
Bosscha Observatory, adjusted to the phases of the ? Lyr system. We obtained 15
spectra, then we calculated their parameters: FWHM, EW, V/R, E/C, ?Vp,
rH?/r*, rHeI 5876 Å/r* and rHeI 6678 Å/r*. Radius calculation shows that these three
lines are in extend process. The second method is implementing the evolution of
the Lyr ? system simulation using MESA software with the MESAbinary
programming code. From the simulation, we obtained the age of the binary
system 2.7 x 107 years, mass and radius of the primary component M1 = 3.54M?,
R1 = 16.1R?, and mass and radius of the secondary component M2 = 13.1M?, R2
= 6.85R?, and Lyr ? system is in non-conventional mass transfer epoch. The two
methods show that Lyr ? system is in non-conventional mass transfer epoch and
the accretion disc will disappear from the secondary component due to the
cessation of mass transfer.
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