Talk:Antares (system)

Looking at where the main world would need to be placed: The Primary is classified as M1.5 Iab-b, placing the secondary (550 AU) at orbit 13 (614 AU). This leaves orbits 0-6 around both stars, and orbit 15+ free. Antares takes orbits 0-5, leaving orbit 6 (with a temperature ~2000 degrees). The Secondary is a B2.5V even orbit 6 has a temperature over 1000 degrees without Antares' factored in). Orbit 15 is -150 thus the sector captial is some sort of enclosed environment.

If we Move Antares B to orbit 12 (307 AU) accounting for some measurement error on today's earth, we can get a viable world at orbit 14. Otherwise Antares woule be a frigid world orbiting about 2500 AU. At night above 45 degree latitude and during the day near the poles the Oxygen would condense out of the Atmosphere forming large lakes of liquid oxygen.

Using the more detailed system in GURPS Traveller: First In. According to the tables, Antares is a M0 Class I star, about 15 solar masses, 3.8 AU in diameter (760 AU to the jump point), and a luminosity of 41,000. The Companion is a B5 Class V star, about 5 solar masses, 0.04AU in diameter (8 AU to the jump point) and a luminosity of 830.

Using the detailed calculations for Antares A I get an Inner radius of 3 AU (yes, Antares is cool enough to have planets inside it), an Inner Life zone of 192 AU, and Outer Life Zone of 263 AU, a snow line of 1012 AU and a outer limit of 600 AU. For Antare B I get an inner radius of 10.8 AU, an inner life zone of 27.3 AU, an outer life zone of 37.5 AU, and a snow line of 144 AU. There will be no orbits around Antares B. The forbidden zone around Antares A is 183 AU to 1650 AU. This does mean it isn't possible to place a world in the life zone of Antares. You need to move the companion out to between 575 and 600 AU (at minimum) to get a world around Antares A.

Another problem is neither star is old enough to have a real planet formed around it. First In notes it generally takes about 500 million years to form a planetary system, and that Antares is probably only a few million years old. It's probably best to assume that the Antares planet wasn't formed in this system, but is an interstellar wanderer captured by the Antares system. The fact that it orbits in an unstable orbit isn't a concern, since Antares will go supernova before the planetary orbit decays enough to render the planet uninhabitable.

So Antares (world) orbits at around 213 AU, taking some 800 years to circle the star. The world probably won't have a moon, though it might have a ring system due to the immense amount of comets in the system.

I really wish I could find Paul Drye's writeup on the Antares Supernova. There was a long discussion on the JTAS boards (now long eaten), but Paul wrote up a summary of the total effects of the supernova. I printed it out, but it seems to have vanished. The imminent nature (at least in stellar terms) should be noted in this article.

Tjoneslo 02:36, 25 October 2007 (UTC)