{Star Cycles (III) [continued (3)] – The Main Sequence}[21st November 1987]

[Redbook4:163-164][19871121:1310b]{Star Cycles (III) [continued (3)] – The Main Sequence}[21st November 1987]

19871121.1310

[continued]

I have misunderstood Chartrand#** (p48): thinking that the labels 'early-type Stars' (O, B, A) and 'late-type Stars' (K, M) referred to development of the individual Stars along a main-sequence lifetime. In fact, the description of a typical life (on Chartrand p. 50-51) makes much more sense (and I am sure that I had understood it before):

[Text of ms diagram above.]

					Gravity
	R[~]				[+]C[I~]				S[~]
			(Creating Iron)	{Closed Groups}	White	White Dwarf
			Yellow	Red Supergiant	A		Blue
				F		B
#*		c.10 billion yrs life	G	The Sun		Early type Stars***	O	A few million years life
								Supernova?
Weak Nuclear Force*	G[~]	Orange	K	Late type Stars****	☼			(Indigo)	M[~]	Strong Nuclear Force**
		c.10,000 billion year life	(H→He) Nuclear fusion	M	(R,N,S?) <880111>
				Protostar Nebula
			Red		Interstellar Cloud		(Violet)
			↑	Gravitat-ional Attraction	Black
	J[~]				A[~]	Dark Cinder or Neutron Star (Pulsar /Black Hole)			U[~]
					Electro[-] magnetic Force					#

#**

*Weak Nuclear Force:

form lightest element (H)

gets rid of electric charge

so E[lectro]M[agnetic]F[orce] does not prevent

creation of Helium etc.

i.e. Changes

electrically charged protons

into electrically neutral neutrons.

**Strong Nuclear Force:

Creating heavier elements (> iron)

(in massive Stars at higher temperature

(Supernova) (more protons per nucleus)

against more powerful electric repulsion.

***Early type Stars:

More massive,

hotter, larger,

brighter;

short-lived.

****Late type Stars:

Less massive,

cooler,

smaller,

duller;

longer-lived.

#Later lives: All become red giant; then:

F5 and cooler	More massive
White Dwarfs	Red Supergiants (some) Explode as Supernova	\
Dark Cinders	Neutron Star (= Pulsar/Black Hole)	}(only the most massive) /

#*cf. S&C.20-2 [presumably original full-length paper version] <930506>

#*[Amateur Astronomy Pocket Skyguide (Newnes)]

#**For Star lives, this circle is unconvincing; for Star types, it is uninformative. <891018> {Try [Clockwise circle from and to +CI~]? – cf. VI.327.}

[continues]

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