Betelgeuse

[Tom Kalbfus]

What if we included this star in the Traveller Universe, a giant red supergiant What use could such a star have in a Traveller campaign? Who would live in this system? Could you refuel your starship in this star's outer envelope?

 

[Anonymous]

Is there a "reliable" estimate of the temperature in Betelgeuse's outer envelope?

I don't recall seeing a temperature range that most Traveller ships are designed to tolerate. Obviously very cold but how hot?

 

[sideranautae]

What if we included this star in the Traveller Universe, a giant red supergiant What use could such a star have in a Traveller campaign? Who would live in this system? Could you refuel your starship in this star's outer envelope?

The coronal temp is too high even with a super Red. Only the coolest Browns are of skim-able temp.


About life zones & time to evolve. From this article: http://en.wikipedia.org/wiki/Red_giant

"Although traditionally it has been suggested the evolution of a star into a red giant will render its planetary system, if present, uninhabitable, some research suggests that, during the evolution of a 1 M☉ star along the red giant branch, it could harbor a habitable zone for several times 109 years at 2 AU out to around 108 years at 9 AU out, giving perhaps enough time for life to develop on a suitable world. After the red giant stage, there would for such a star be a habitable zone between 7 and 22 AU for an additional 109 years."

 

[Tom Kalbfus]

One Particular thought. Betelgeuse is the type of star that goes supernova when it exhausts the fuel at its core. One can initiate a jump at the star's surface and even some distance inside the star. Suppose they could figure out exactly when the star is going to go supernova and it was soon? What type of research you think the Imperium might do here. One thing to remember the hydrogen doesn't circulate from the outer envelope to the core, so when the core supply of hydrogen or whatever is exhausted, their is still plenty of fusion fuel or hydrogen in the outer envelope.

 

[GypsyComet]

Betelgeuse is some five sectors rimward of Terra, so any expeditions are not trivial undertakings.

 

[sideranautae]

One Particular thought. Betelgeuse is the type of star that goes supernova when it exhausts the fuel at its core. One can initiate a jump at the star's surface and even some distance inside the star.

Not in MGTraveller you can't. What game are you referring to?

 

[Tom Kalbfus]

One Particular thought. Betelgeuse is the type of star that goes supernova when it exhausts the fuel at its core. One can initiate a jump at the star's surface and even some distance inside the star.

Not in MGTraveller you can't. What game are you referring to?

okay what would be the jump radius of a 20 Solar Mass Black Hole. The thing is, a 20 solar mass black hole has the same mass as a 20 solar mass red supergiant, so outside the outer envelope of Betelgeuse and the same distance from the center of mass of the black hole, the gravitational fields are the same. I'll calculate the event horizon of a 20 solar mass black hole to make it official.
According to this site http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/blkhol.html the radius of a 20 solar mass black hole is 59.02379215674582 km according to the 100 diameter rule, the jump radius should be 11,804.758431349164 km for a 20 Solar Mass black hole since the mass is the same as Betelgeuse why should the jump radius be different from Betelgeuse?

 

[sideranautae]

okay what would be the jump radius of a 20 Solar Mass Black Hole.

I understand what you are saying. One point you have missed. Where in MGT does it state the 100D limit is based on a specific density? And, what is that specific density?

 

[Wil Mireu]

okay what would be the jump radius of a 20 Solar Mass Black Hole. The thing is, a 20 solar mass black hole has the same mass as a 20 solar mass red supergiant, so outside the outer envelope of Betelgeuse and the same distance from the center of mass of the black hole, the gravitational fields are the same. I'll calculate the event horizon of a 20 solar mass black hole to make it official.
According to this site http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/blkhol.html the radius of a 20 solar mass black hole is 59.02379215674582 km according to the 100 diameter rule, the jump radius should be 11,804.758431349164 km for a 20 Solar Mass black hole since the mass is the same as Betelgeuse why should the jump radius be different from Betelgeuse?

For a Traveller jump drive, the 100D limit is based on the star's radius, not its mass or gravity or density. Since the star is about 5 AU in radius (10AU diameter), Betelgeuse's 100D radius would be 1000AU. That is a huge distance, and not somewhere that you want to be the wrong side of the jump shadow of!

There have been unofficial/fan-made variants based on gravity or tidal radius that you may be confusing this with (personally I think those are far better, but that's not canon).

 

[GypsyComet]

"House rules" and prior edition solutions are not out of place here, though having them clearly labeled as such is a good idea. Mass-based jump horizons are a fan variant older than Mongoose by quite a bit.

 

[Tom Kalbfus]

okay what would be the jump radius of a 20 Solar Mass Black Hole.

I understand what you are saying. One point you have missed. Where in MGT does it state the 100D limit is based on a specific density? And, what is that specific density?

I take the 100D limit as a rule of thumb when dealing with Earth like planets with Earth like densities, planets such as the Earth, Venus, Mercury, Mars, and the Moon are close enough in density that the 100D limit is a good approximation for the Jump limit, that is my house rule, planets such as Saturn, Jupiter, Uranus, and Neptune are constructed differently. The Sun and other stars are also less dense than the Earth, a black hole, a white dwarf, and a neutron star are also greatly more dense, now I believe the 100D limit was designed specifically for terrestrial planets like Earth, as those are the sort of planets that players will likely go adventuring on and therefore b of interest to them. The cube root of mass rule is the house rule I prefer because it takes the mass of whatever object and by taking th cube root of it when measured in Earth masses, you get what its diameter would be if it had the same density as Earth, then you multiply that by 100 to determine the Jump radius, this produces a more rational result that simply taking 100 diameters of whatever it is no matter how wispy or how dense it is. What if for instance you take 100 diameters of a nebula of an exploded star with a pulsar at its center, such as the crab nebula? The Crab nebula is 3.4 parsecs wide, that means its jump limit is going to be 340 parsecs if you hold to that official rule slavishly, I tend to think one shouldn't do that and that one should be allowed to make jumps from within the nebula and to inside the nebula. I think the cube root mass rule is better, so I use it in situations like this, using the cube root mass rule, you take the cube root of the mass of the Crab Nebula Pulsar, find out what its diameter would be if it had the same density as Earth and then take a radius 100 of those diameters out to find the jump limit from that star, I think the wispy clouds can be ignored for jump purposes, as they don't make compact objects like stars in this instance.

 

[Rikki Tikki Traveller]

Rather than Betelgeuse, consider Antares. That star is within Charted Space and there was a fan project a while ago about what would happen if/when Antares goes supernova...It was not good.

 

[Tom Kalbfus]

Rather than Betelgeuse, consider Antares. That star is within Charted Space and there was a fan project a while ago about what would happen if/when Antares goes supernova...It was not good.

Here are some facts on Antares: http://en.wikipedia.org/wiki/Antares
It has about 18 times the mass of our Sun. and a radius about the size of our asteroid belt, it is a problem for Charted Space, so I imagine the Imperium would have a research station in the Antares System, because they would want to know when Antares is going to go supernova, and what can be done about it. What if they had a research project as well a jump drive that is triggered by a supernova. Suppose the energy of a supernova could be directed to making a super-jump to another galaxy, say M31 for instance? Getting the jump to include the entire star would be the trick.

 

[sideranautae]

There have been unofficial/fan-made variants based on gravity or tidal radius that you may be confusing this with (personally I think those are far better, but that's not canon).

A couple years ago I saw some house rule based on tidal. Not here but some other forum. Looked better than 100D method. I just can't remember the specifics.