Astr 221 Homework #6 -- Due Nov 18

1. Visual Binaries

Sirius is a visual binary with a period of 49.94 years. It has a parallax of 0.377 arcseconds, and the semimajor axis of the true relative orbit is 7.62 arcseconds. The ratio of the distances of Sirius A and Sirius B from the center of mass is a(A)/a(B)=0.466. Sirius A has an apparent bolometric magnitude of -1.55, while Sirius B has an apparent bolometric magnitude of 5.69.

2. Recreating the Main Sequence

3. Equation of State

4. The Rigel Incident

On the way to the star cluster, the USS Asinus receives a distress call from the direction of Rigel (Rigel is a blue supergiant, with a luminosity of L=40,000 Lsun, and temperature T=11,200K). The message reads as follows:
Calling USS Asinus. This is Agricultural Outpost Nine, on a planet orbiting Rigel at a distance of 1 AU. Three Hoarsflize battleships have entered our system and have taken up a strategic position 10 AU away from us. We suspect attack is imminent. Can you evacuate our people?
Now normally even the mighty Asinus would be no match for three heavily armed Hoarsflize battleships. But on this mission we are testing out a new cloaking device, the NoVu9000, which absorbs all energy it receives. This is particularly useful against Hoarsflize sensors, which use AEP (active electromagnetic probing) technology. The only problem -- the NoVu9000 has been tested in deep space, but never close to any stars.

The NoVu9000 works by setting up a cloaking field with a 1 km radius around the Asinus. However, it is very sensitive to strong radiation -- if it absorbs more than 5x1024 ergs of energy it will fail.

Question 1: How much time would we have to evacuate the Outpost before our cloaking device would fail?

Even with the cloaking device blocking the Hoarsflize's AEP sensors, it is still possible that they could make visual contact with the Asinus (why?). The cameras onboard the Hoarsflize warships are still fairly sensitive, able to detect objects down an apparent visual magnitude of about mV = 9.5.

Question 2: Could the Hoarsflize warships see us even if we were cloaked?

To evacuate the outpost will take 30 minutes, if we can avoid the warships. If the warships see us, we're toast. And if we don't save the outpost when we could have, we'll all be busted down to privates by Starfleet.

Make a Decision: Rescue or not?