Thursday 9 October 2014

1D Solar Atmosphere Models in IDL: Maltby et al (MACKKL)

Here I add files containing the one-dimensional models of the solar atmosphere from the famous paper of Maltby et al (1986, 1986ApJ...306..284M). There is a quiet sun model and three models of the sunspot atmosphere (L, M, E corresponding to the late, mid and early cycle of the solar activity). For the details of these models please check the paper.

The data in the files comes directly from Tables 7, 8, 9 and 11 of Maltby et al. The variables stored in the original models are:
  • geometrical height scale, 
  • column mass scale, 
  • optical depth at 5000 A, 
  • temperature, 
  • turbulent velocity, 
  • number density of hydrogen, 
  • electron density, 
  • total pressure, 
  • ratio of gas pressure to total pressure, 
  • density.

Fig. The temperature stratification of the three sunspot models (remake of Fig.8 of Maltby et al)

Saturday 31 May 2014

Theory vs. Observations, by Jean-Claude Pecker

A cartoon by the famous French astronomer Jean-Claude Pecker (published in the Proceedings of the 3rd European Solar Meeting, "Solar activity, April 13-15 1981, Oxford", ed. C. Jordan; a non-ADS volume).

No matter how much we pushed the frontier of the science and how much our theoretical machinery, diagnostic tools and large and expensive gadgets evolve, this is still in a way very actual. It is important not to forget that even the most sophisticated realistic 3D models of the sun are still mammals, pardon, models. On the other hand, the results of the observations should not be consider  as the real "elephant" either. They are pictures of the elephant made with imperfect instruments!

Sunday 18 May 2014

Eddington on Icarus

From the Presidential Address of Professor Arthur Eddington to Section A of the British Association in Cardiff, August, 24th, 1920 (1920Obs....43..341E, also in the book Stars & Atoms,

"In ancient days two aviators procured to themselves wings. Daedalus flew safely through the middle air and was duly honoured on his landing. Icarus soared upwards to the sun till the wax melted which bound his wings and his flight ended in fiasco. The classical authorities tell us, of course, that he was only doing a stunt; but I prefer to think of him as the man who brought to light a serious constructional defect in the flying-machines of his day. So, too, in science. Cautious Daedalus will apply his theories where he feels confident they will safely go; but by his excess of caution their hidden weaknesses remain undiscovered. Icarus will strain his theories to the breaking-point till the weak joints gape. For the mere adventure? Perhaps partly, this is human nature. But if he is destined not yet to reach the sun and solve finally the riddle of its construction, we may at least hope to learn from his journey some hints to build a better machine."

Landscape with the Fall of Icarus by Pieter Bruegel the Elder (Musées royaux des Beaux-Arts de Belgique).

Sunday 2 February 2014

Diatomic partition functions in IDL

Recently I posted a set of IDL routines for the atomic partition functions (PF) based on various polynomial fits that are available in the literature. Here I do the same for the diatomic molecules.

The routines for the diatomic PF use an internal catalog of 325 diatomic molecules. The ionized molecules are separate entries. The catalog is stored as an IDL structure in catalogue_of_diatomics.sav. The structure has the following tags for every molecule:

Chemical formula, e.g. 'H2', 'CO', 'H2+'
NcNumber of constituents, always 2 for diatomics
NucNumber of uniq constituents, e.g. 2 for CO, 1 for H2
ConstituentsConstituent atoms, e.g. ['H', 'H'], ['C', 'O']
ChargeCharge, e.g. -1, 0, +1
CodeKurucz's code for molecules, e.g. CO '0608.00'
D0Dissociation energy in eV
DataList of internally available data sets for this molecule
TypeType of data: pf for partition function, kp for chemical equilibrium constant, eint for internal energy (one entry for each dataset)
ReferencesList of ADS references (for each dataset)