Nightfall: Can Kalgash Exist: Observables

Authors:

(1) Smaran Deshmukh, Email: [email protected];

(2) Jayant Murthy, Indian Institute of Astrophysics, Bangalore 506034, India ([email protected]).

Table of Links

The following have been stated in the book (All page number refer to the 1991 edition (Asimov & Silverberg, 1991):

Kalgash orbits Onos which is a yellow star at a distance of 1.2 AU (pg. 185)
Trey and Patru are a close binary pair and appear white in color. They are faint and so must be white dwarfs (pg. 3)
Tano and Sitha are another close binary, also white in color at a distance of 13.2 AU from Onos. They are, brighter than Trey and Patru but still too faint to be main sequence stars and are also likely to be white dwarfs (pg. 6)
Dovim is a red star (pg. 78).
The furthest sun from Kalgash is 110 lightminutes away (13.4 AU), or somewhere just outside the orbit of Saturn as seen from the Sun (pg. 185)
The six suns of this system are the only stars in the Universe observable from Kalgash under normal conditions. Once every 2049 years, there is an eclipse of Dovim when no other of the suns are in the sky and the sky becomes dark enough to see the stars in the nearby cluster, contributing to the madness (pg. 111).
The Kalgash system is surrounded by a cluster of bright stars which are ordinarily, as mentioned above, not visible (pg. 215).
Astronomers at the beginning of the story discovered that Kalgash had a moon of about the same size. It eclipses Dovim every 2049 years at which time its angular diameter is seven times than that of the star. This results in a total eclipse and therefore darkness for a period of 9 - 14 hours, depending on latitude; long enough to ensure that every part of the planet experiences a period of darkness (pg. 114)

This paper is available on arxiv under CC BY 3.0 DEED license.