At first the Blamer lines to confirm the spectral class A:
|Instrument: NESSIE4, Date: Feb-Mar 2001|
At a first glance the spectrum looks a little bit noisy compared to Vega. But Sirius belongs to a special group of A-type stars the Am stars. Sirius is a moderate member of this group with not so strong metallic lines.
Ok. Now lets stroll through the spectrum and see what we find.
Our CCD becomes rapidly insensitive below 4000 Å. We think the emissions inside CaII and H10 are rather noise then signal. Anyway CaII at 3933 is weak due to the high temperature of the photosphere of Sirius.
A detailed view onto the region between H-gamma and H-beta
We use the region 4900 Å to 5500 Å to compare the abundances of metalls in Sirius and Vega.
Literature used to discuss the spectrum of Sirius:
Jaschek&Jaschek: The Classification of Stars
Weaver, Wm.B., Torres-Dodgen, A. 1995, ApJ, 446, 300-317
Sandakane, K., 1989, Pupl.Astron.Soc.Japan 41, 279-288
Gehlich, U.K., 1696, Astron. & Astrophys. 3, 169-178