September 12, 2011
At this time I am attempting to straighten out all legal details involving Greenwood Research, so that state taxes will be paid on direct orders as Amazon handles them, and so forth. Greenwood Research will probably incorporate in the near future.
Greenwood Research books and software have been re-scanned and edited to eliminate all minor spelling and typographical errors that crept into previous editions. This has been approached as a change in the state of the art, and is not supported by a new ISBN edition number. Minor changes in the state of the art are dated State: month/day/year. On-line sample plates and software will be similarly upgraded in the next few days. Recompiled software for spelling-corrected output will become available on-line later this week.
Feb 24, 2004
The STAR8 2nd-order structure stellar evolution investigator is now available free on-line to supplement the 2nd edition of Thermonuclear Fusion in Stars by James A. Green. Press here for the solar star8.txt printout.
Jan 29, 2004
By now 43 pages of the 160-page Gravitation & the Electroform Model have been placed on-line to supplement summary and book review material.
 FUSION - August 23, 2003 2:06 PM CST
The Star Age listing now notes that the first star age calculation based on constant luminosity is the best one, and that the 2nd star age calculation based on the constant-radius assumption is in error. It has been retained to review the impact of the constant-radius assumption error. In reality, the constant-luminosity theory of the stellar evolution of the Sun is canonical and better than the constant-radius theory. As fuel is consumed in the core, the star shrinks a little to maintain hydrostatic equilibrium as the radiation pressure goes down, raising its gas pressure, which is proportional to (1/R)**4. Then a small change in the radius can keep the gas + radiation pressure nearly constant, keeping the star nearly the same radius. In the Sun's case, R shrinks by about 1% over 4.5 billion years. This would be enough to nearly double fusion energy generation if fuel were not consumed in the core, however. In reality, there never was a time after stable equilibrium was achieved when the solar luminosity differed much from the present luminosity. The sun was a little larger initially, however. This means the first number we compute for the age of the Sun is much better than the second number, which assumes a constant solar radius and a higher initial luminosity. To update, download fusion.zip, unzip to extract fusion.exe with WinZip, and run. The on-line reference files starz7ag.cpp and starz7.cpp have been slightly modified.
 FUSION - August 22, 2003, 10:00 PM.
A change to starz7ag.cpp was introduced to add a 2nd star age based on the 1st-order average luminosity of the star since star formation. The original calculation assumes that the star has had the present luminosity all along. Our 1st-order estimate here assumes that the initial luminosity is the nuclear luminosity we initially compute, (actually an overestimate, because the Sun can shrink to maintain equilibrium) which produces an interesting lower bound to the age. Thus the average luminosity employed for the 2nd age estimate is
L_avg = (L_nuc_calc + L_star_observed)/2.0.
This seems to produce a star age that is too low, so we conclude that a non-linear burndown has taken place in which the initial luminosity of the Sun went fairly rapidly down to something close to the present luminosity. This assumption could be modeled with a variational technique to estimate the time-history of the solar luminosity by matching its known age obtained via radioisotope studies to its computed age by flexing a variational parameter.
To install this change, download fusion.zip, unzip, and run. starz7ag.cpp has been updated on-line.
 FUSION, August 21,2003 3:42 P.M., Thursday.
The surface temperature information for Sirius A was also updated in z6near.txt. Therefore you should replace z6near.txt by clicking here for z6near.txt, and then writing it to your \z6 sub-directory to replace the old version, if you downloaded your files prior to August 21, 2003, 3:42 P.M., Thursday.
 FUSION, August 21,2003 12:49 P.M., Thursday-
___Information for Sirius A was not properly entered into the file z6brite.txt. Sirius was identified has having type G2 V instead of spectral type A1 V. The on-line file z6brite.txt has been updated to fix the problem. If you uploaded z6brite.txt prior to Aug.21, 2003 12:49 P.M., you will have to get a fresh copy of the file at zip/z6brite.txt. The star Sirius A still looks a bit underluminous after this fix, at L_nuclear/L_SiriusA = 0.9331, perhaps due to an error in the distance. A precise description of the surface temperature might also help. If the distance is taken to be 8.5 LY (instead of 8.6 LY), then L_nuclear/L_SiriusA = 1.041834, so that the Clayton age of Sirius A obtained by decreasing the hydrogen abundance in the core until L_nuclear/L_SiriusA = 1.0 would then be 86 million years.
Using alternate data on Sirius A to (8.7 LY, m=-1.42, A1, 10265 degrees Kelvin), and using the surface temperature 10265 degrees Kelvin, L_nuclear/L_SiriusA = 0.995219, just a little too low to derive a sensible age for the star. Then wiggling the distance to 8.6 LY yeilds L_nuclear/L_SiriusA = 1.11047, so that the Clayton-formula age of Sirius A would be 0.2199 billion years.