Helliconia Summer - Brian W. Aldiss [639]
Such matters are not generally the subject of literature. But I felt the necessity, as you see, to have a shot at incorporating them.
Now at last I have done. The rambling edifice of Helliconia is before you, with my hopes that you will enjoy the results.
Your affectionate
Father
Boars Hill
Oxford
APPENDICES
PHAGOR
APPENDIX 1
Cosmological
Star A (later known as Freyr) once had a companion star (Star C).
Eight million years before the narrated events, Star B (later known as Batalix) came within the gravitational field of Star A. In the orbital disturbances which followed, Star C escaped entirely, while Star B was captured. Henceforth, it formed the inferior partner of a binary system. The properties of the binary suns are as follows:
STAR A
Mass 14.8 mass of Sol (Earth’s sun)
Luminosity 60,000 × solar luminosity
Temperature 11,000 Kelvin
Radius 65 × radius of Sol or 28,112,500 miles
Spectral class A-type supergiant
Colour white
Star A is between 10 and 11 million years old. It has evolved away from the main sequence and is already entering old age.
At the time of its capture of Star B, it was less luminous but hotter. So for the first million years or so after capture, the planets of Star B were subjected to far more UV radiation than at present. X-ray and UV radiation resulted in accelerated evolution of present species.
Star A evolved no planetary system. Orbiting stellar debris was drawn into it and consumed.
STAR B
Mass 0.96 × mass of Sol
Luminosity 0.8 × solar luminosity
Temperature 5600 K
Radius 0.94 × solar radius or 406,550 miles
Spectral class G4
Colour yellow
Star B has four planets in orbit. They are, working from inner to outer, Copaise, Aganip, HELLICONIA, and Ipocrene.
In the period before Star B’s capture, a moon was in orbit about Helliconia which was lost during the disruption of capture.
Figure 1. Birth of a new binary system.
A shows the solar system of Star B (Batalix) and its four planets coming close to a binary system consisting of a large A-type supergiant star, Star A (Freyr), and its companion, the G-type star, Star C. Disturbance begins.
B shows resulting gravitational disruptions, causing Star C to ‘escape’, as the Star B system is drawn into Star A’s influence. The moon of one of the planets of Star B (Helliconia) is lost to the system, drifting away in the general direction of Star C.
C shows that now a new binary system has been formed. Star B and its attendant planets are in orbit about the supergiant Star A.
Locations
As located from Earth, the binary system of stars A and B lies in the constellation Ophiuchus (The Serpent-Bearer). The main body of a dark dust cloud lies close to the neighbouring constellation of Scorpius, at a distance of 700 light years from Earth. It conceals a cluster of comparatively young stars, with Star A among them.
Star A is just north of Antares. Location: Right Ascension 16h 25m. Declination: – 24° 30 ′.
Helliconia’s first designation on terrestrial charts: Planet G4 PBX / 4582–4–3.
Helliconia’s Composition
Helliconia is a planet with roughly terrestrial properties.
Radius 4800 miles
Circumference 30,159 miles
Mean density 4.09
Mass equivalent to 1.28 Earth’s mass
Axial inclination of rotation axis to the plane of orbit 55°
This compares with about 66° for Earth.
This widens the range of temperatures within climatic zones.
The atmospheric composition varied slightly from pre-capture to post-capture. A greater amount of carbon dioxide in the air, pre-capture, produced a mean temperature of – 7°C. After capture, and at periastron (when Star B and planets are at their closest to Star A), some of this atmospheric CO combined with water to form carbonate rocks.
Atmospheric carbon dioxide is thus reduced, so