Typical nebulae sizes and masses

[jnb]

I've been sitting here and working out some numbers for the stability of nebulae and how they collapse (the sort of thing that I do while on holiday) and I can model the collapse, ir radiation, and fragmentation of a nebula but does anyone have any figures for 'typical' nebulae sizes and masses?

 

[Tim]

Nope. But perhaps you can help with something I have been wondering about forever.

So, Betelgeuse goes SN. How long until we see it from earth the same apparent size as M57? M27? NGC 6990-6992 ?

Thanks. I can't do maths, don't have the brain.

[vlaiv]

I guess that they will vary considerably by type.

Probably easiest to figure out (order of magnitude) would be planetaries / SN remnants. Just take solar mass needed to go nova / supernova (upper bound would be black hole I guess) and respective neutron stars. Most of difference in mass will be in ejected shell (you can even account for radiation released in the process, but I suspect it will be well below 1 percent).

As for angular size - and expanded shell size - good plantarium software could give examples on those (as well as expansion speed in case of some nebulae of known age like M1 - Crab).

[jnb]

I should clarify that. I'm talking about diffuse nebulae that are collapsing to form stars and not planetary or SN remnants. They by their nature gave to be stellar masses so are easy to estimate.

 

[MarsG76]

I cant say I ever though of nebulae sizes and masses but in this case Google is your best friend.

[jnb]

39 minutes ago, Tim said:

Nope. But perhaps you can help with something I have been wondering about forever.

So, Betelgeuse goes SN. How long until we see it from earth the same apparent size as M57? M27? NGC 6990-6992 ?

Thanks. I can't do maths, don't have the brain.

Haven't got the data to hand but a quick back of envelope calculation suggests that the crab nebula is about 10 times the distance so it would take about a century to reach the same apparent size. ( crab nebula is 6500 ly distant and was seen to gov nova in 1054, Betelgeuse is about 650 ly distant)

 

[vlaiv]

Well if it helps, Orion nebula is estimated to have 2000 solar masses.

I wonder if there is something like average density of emission nebulae - that, coupled with diameter would give you estimate of their masses?

[vlaiv]

Here is interesting read:

http://astronomy.swin.edu.au/cosmos/E/Emission+Nebula

" Their mass generally ranges from 100 to 10,000 solar masses and this material can be spread over a volume of less than light year to several hundred light years. For this reason, their densities are highly varied, ranging from millions of atoms/cm³ to only a few atoms/cm³ depending on the compactness of the nebula. "