Violet star

At some point, the Sun becomes so extended that the surface gravity is too weak to hold the atmospheric gas dust, and this mixture blows out of the star as a stellar wind. The Sun in this state is called a planetary nebula, with a hot central blue-violet star surrounded by rings of yellow and red. The rings are made of material from the Sun that has been blown into space. The core becomes a white dwarf (figure 7.8). 

Violet Stars.—Chlorate of potash 9 ports nitrate of strontia, 4 ports sulphur, 6 parts carbonate of copper 1 part calomel, 1 part mastic, port. 

Violet Stars.- Chlorate of potash, 9 parts nitrate Of strontia, 4 parts sulphur 6 parts carbonate of copper, 1 part calorud 1 part mastic 1 part. 

Figure 10 N M R structural analysis of carrier domains. Three conformations of the PCP domain from tyrocidine synthetase (brown box) and the NMR structure of the related AGP domain from a polyketide synthase. The star symbol signifies the position of the conserved phosphopantetheinylated serine residue. The protein ribbon representations are rainbow colored from red (N-terminus) to violet. PDB codes A/H state, 2GDW H-state, 2GDX A-state, 2GDY AGP, 2AF8.

Each star follows a different path and at a different rate. Ageing stars turn red, except for the most massive, which become violet or even ultraviolet, gradually moving away from the main sequence. Their core temperatures and pressures increase, thereby triggering further nuclear reactions which can build carbon from helium as the stars ascend the giant branch. The construction of nuclear species in massive stars reaches its apotheosis in the explosion of type II supernovas. 

Burning stars, such as those originating from Roman candles or shells (Figure 8.5), emit radiation in the ultra-violet, the visible, near-infrared and mid-infrared regions of the electromagnetic spectrum, as displayed in Figure 8.6. 

The difficulty in producing a good blue flame stems from several important considerations. Firstly, impurities in the chemicals present in the firework tend to produce yellow flames, which detract from the blue secondly, coloured flames follow similar physico-chemical phenomena but operate in different regions of the spectrum. Consequently the copper salts (that are normally utihsed for the production of blue stars) decompose thermally to produce a variety of emissions that radiate from about 325 to 660 nm i.e. from green, blue and violet to orange-red) simultaneously polluting the pure blue flame which appears in the 400 to 455 nm region. 

L. Comp a luce violetta per stelle (Compn for violet light star) KC103 58.5, Sr(Cl03)2 14.5, CuC03 10, gumlac 7 S 10% (Izzo, p 215)... 

The first two compounds are greenish blue, the latter are light violet in colour. All are crystalline, and separate in star-like crystals. In concentrated solution the separation of the compounds is almost quantitative.5... 

The light of the flare is rather pale and the smoke lines are yellow, but we don t sense the colours, merely the contrast between the brilliancies rather like a black and white drawing. Another of the extremes may be the "Flower in the Sunset", which is a smoke flower with red stars of high brilliancy as the pistils. In this case only the red of the pistils meikes a deep impression, and any coloured smoke red, yellow, green, blue or violet can serve as petals because it has only an auxiliary effect against the pistils. 

Neon Results by [43] from Ne I and Ne II lines in nearby, early type B stars yield log A(Ne) = 7.97 0.07, which can be taken as characteristic of the present day ISM. If neon contributions from more massive AGB stars to the ISM over the past 4.6 Gyr are negligible, this value may be taken as representative for the Sun. Landi et al. ([44]) obtained A(Ne) = 8.11 0.1 from solar flare measurements in the ultra-violet. This Ne abundance is derived independently of the O abundance, unlike other Ne abundance determinations that rely on Ne/O ratios and an adopted O abundance (see e.g., [13] and below). 

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