Figure 1. Comparison of A and Be Star Spectrum
HIP 4436
μ Andromeda (Pronounced Mew) or HIP 4436 as in Hipparcos Catalogue (not Hipparchus.. there is a difference) , is a famous star for Star hoppers; they use it to find Andromeda galaxy. It sits in between Mirach and this galaxy. It is some 130 light years away from us and is bigger, brighter and hotter than our own Sun.
How big is it? Double the mass of our Sun, 2.4 times the Sun’s radius and estimated to be 600 million years old. It is a “Main Sequence” Star, which means it is fusing Hydrogen in to Helium in it’s core. It has a spectral class of A5V.
Read the news here of “unsual signals” coming from this star, which were recieved by the Breakthrough Listen Project. The project was searching for Life in the Universe. I don’t think there is an exoplanet around this star and have no idea why they included this star in their survey. They wrote a paper in 2018.
Pleione
Not the beautiful plant which have the same name as of a very special B type star with an “e” in it. Pleione is the 7th brightest star in the group of pleiades cluster of stars.
Pleione is a Main Sequence star with absorption lines in its spectrum and emission lines and has emission lines coming out of the two gaseous disks at different angles to each other; a lot of work has been done to understand the disk models around this star.
Pleione is 450 light years away from us in the constellation Taurus and has a magnitude of 5.
Figure 1 shows an Instrument Calibrated Flux of these two stars. Complete Spectroscopy equipment has many parts which behave differently so we need to calibrate our instruments with a standard so the flux can be adjusted properly.
You can see the Spectral Energy Distribution.. a lot of energy is in the bluer portion of the electromagnetic radiation.
In my spectrum comparison (Figure 2), Hα line in HIP 4436 A type star shows a clear absorption line (Red Profile). And at the same wavelength, there is a strong emission line in the spectrum of Pleione Be star which is indicative of the disk around this star.
In Figure 3, Hβ line comparison also has clear difference. A star has a normal absorption line but the Be star has two absorption lines with an emission line in the center.
Figure 3. Hβ line comparison
Figure 2. Absorption and Emission at Hα line
In Figure 4, Ca K and H absorption lines are present in A star but in Be K absorption line is absent.
Figure 4. Ca K and H comparison