SPECTRAL ANALYSIS

  Spectrum analysis is a scientific method of charting and analyzing the chemical properties of matter and gases by looking at the bands in their optical spectrum.  This can be done with the BDI telescope setup by putting a diffraction grating in front of the CCD Camera.  I use a Start Analyser.  Below you can see how the light from the object produces a spectrum.  I analysed the spectrum with a software package called Visual Spec.  The following are some of the objects I have studied.
 

The Redshift of Quasar 3C273

 

I measured the redshift by comparing the  emission lines of Hydrogen (both Alpha and Beta in the Balmer Series).

In this case, 3C 273 had its Hydrogen Beta line, Hb, (normally 4861.33 Angstroms) shifted to 5679 Angstroms. Using the formula:

I arrive at a value of z = 0.1682.

The quasar however is moving at relativistic speeds, a slight modification of the formula should be taken into account, so I used the following:

Plugging the value for z into the above equation yields a value of z = 0.1542, which is close to the expected 0.158339 as published by professionals.

The distance to 3C 273 depends on the value of Hubble's Constant (H). If H is 75, then 3C 273 is about 2 billion light-years away. If H is 60, then 3C 273 is about 2.6 billion light-years away.   That would make it as bright as 100 times the combined light of all the stars in our Milky Way Galaxy.

 

 

I also measured the spectrum of QSO PKS2155-304 unfortunately however I was not clearly able to determine the emission lines of Hydrogen so I could not do a similar analysis.

 

 

The reflective spectra of Neptune

 

 

We see Neptune visually by the light from the sun that is reflected from its clouds and scattered by its upper atmosphere (there is no solid surface to reflect light, as there is for the terrestrial planets). The emission lines in the red portion of the spectrum (6200 - 7500) are due to the absorption of methane (CH4) molecules in the outer atmosphere of Neptune. With so much red removed from the reflected radiation, the planet appears blue-green in color.

 

 

Spectra of Nova in Sagittarius 2008

 

 

A nova is a cataclysmic nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star (Wikipedia).

 

The reflective spectra of 2 Asteroids

Below are the reflective spectra of 2 asteroids, 7 Iris and 16 Psyche.  Most analysis of the reflective spectra of the regolith of asteroids seems to be in the infrared spectrum.  I could not find any definitive information to guide my analysis of the spectra however below is the result of bit and pieces I've managed to google on the subject. I am making assumptions and more research is required.

Space weathering of the regolith which is caused by the Impact of micrometeorides and solar and interstellar radiation (cosmic rays) cause the reduction of iron (FeO => Fe + O)

The only prominent absoption I could see in the spectra was at about 5170A.  I assume this is caused by the FE (5167.49) in the regolith

 

 

Asteroid (7) Iris is a S-type which are of a silicaceous (stony) composition, hence the name. Approximately 17% of asteroids are of this type, making it the second most common after the C-type (Wikipedia)

 

 

Asteroid (16) Psyche is a M-type which are asteroids of unknown composition; they are moderately bright (albedo 0.1ľ0.2). Some, but not all, are made of nickel-iron, either pure or mixed with small amounts of stone. These are thought to be pieces of the metallic core of differentiated asteroids that were fragmented by impacts. They are thought to be the source of iron meteorites. (Wikipedia)

 

 

Wolf Rayet Stars

Wolf-Rayet stars (often referred to as WR stars) are evolved, massive stars (over 20 solar masses), and are losing their mass rapidly by means of a very strong stellar wind, with speeds up to 2000 km/s. While our own sun loses 10E-16 of its own mass every year, a Wolf-Rayet star loses 10E−5 solar masses a year. These stars are also very hot: their surface temperatures are in the range of 25,000 K to 50,000 K. (Wikipedia)

Wolf-Rayets stars are divided into 3 classes based on their spectra, the WN stars (nitrogen dominant, some carbon), WC stars (carbon dominant, no nitrogen), and the rare WO stars with C/O < 1.

 

 

The WC stars optical spectra show emission lines from H, CII, CIII (5696┼), CIV (5805┼), OV (5592┼), HeI, and HeII. No nitrogen lines are seen in the WC stars.

 

 

The WN stars optical spectra show emission lines from H, NIII (4640┼), NIV, NV, HeI, HeII, and from CIV at 5808┼.

 

   
 

Miscellaneous Stars

 

 

Spica's spectral class is B1V

Class B stars are extremely luminous and blue. Their spectra have neutral helium, which are most prominent at the B2 subclass, and moderate hydrogen lines. Ionized metal lines include Mg II and Si II. As O and B stars are so powerful, they only live for a very short time, and thus they do not stray far from the area in which they were formed. These stars tend to cluster together in what are called OB associations, which are associated with giant molecular clouds. The Orion OB1 association occupies a large portion of a spiral arm of our galaxy and contains many of the brighter stars of the constellation Orion. They constitute about 1 in 800 main sequence stars in the solar neighborhood Śrare, but much more common than those of class O (Wikipedia).

 

 

 

Delta Virginis' spectral type is M3III

Class M is by far the most common class. About 76% of the main sequence stars in the solar neighborhood are red dwarfs (78.6% if we include all stars) such as Proxima Centauri. M is also host to most giants and some supergiants such as Antares and Betelgeuse, as well as Mira variables. The late-M group holds hotter brown dwarfs that are above the L spectrum. This is usually in the range of M6.5 to M9.5. The spectrum of an M star shows lines belonging to molecules and all neutral metals but hydrogen lines are usually absent. Titanium oxide can be strong in M stars, usually dominating by about M5. Vanadium oxide bands become present by late M (Wikipedia).

 

 

 

Theta Virgo's spectra class  is A1V

Class A stars are amongst the more common naked eye stars, and are white or bluish-white. They have strong hydrogen lines, at a maximum by A0, and also lines of ionized metals (Fe II, Mg II, Si II) at a maximum at A5. The presence of Ca II lines is notably strengthening by this point. They comprise about 1 in 160 of the main sequence stars in the solar neighborhood (Wikipedia).