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Author Topic: A Sort of Problem  (Read 5232 times)

karakris

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A Sort of Problem
« on: February 09, 2013, 09:57:08 AM »
I have tried to study Astrophysics - but I am not very clever at it, so I am asking if there is someone clever enough here, to work out a sort of problem.

Riight - here we go - The Iota System.

Star Iota A - A Type 'T' ( Methane Type ) Brown Dwarf Star
Mass -  28,602 x Earth Mass ( 0.08589 x Solar Mass )
Diameter - 150,000 Km
Average Surface Temperature - 980 degrees Celsius.

Planet "Jinx"
0.9 x Earth Mass

Star Iota B - A Type DO White Dwarf Star
Mass - 170,800 x Earth Mass ( 0.513 x Solar Mass )
Average Surface Temperature - 30,000 degrees Celsius

I have left out a lot of other details of the System, which are not relevant to the problem.

Obviously the Star Iota A will be in orbit around the much more massive Star Iota B.
The Planet "Jinx" is in orbit around the Star Iota A.

Now, this System has been deliberately "engineered" - so that the Planet "Jinx" is always in a direct line between the Star Iota A and the Star Iota B.
This means that at all times, some part of the rortating Planet "Jinx" will be facing towards the Star Iota A - whilst the opposite side will be facing towards the Star Iota B.

I need to find a way to determine where the orbit of "Jinx" lies in orbital distance from Iota A.
Correspondingly - it would be useful to know the length of one "Year" of Jinx in its Orbit.

Secondly - as the actual amount of Radiation from the White Dwarf will be 100 times that of Sol -
What I am proposing is that "Jinx" is habitable - being primarily lit by Iota B, with its "nights" being lit by the duller deep red-violet light of Iota A.
I need  to know if this is actually feasible.



 

Tass

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Re: A Sort of Problem
« Reply #1 on: February 09, 2013, 10:13:37 AM »
It is not possible, sadly. Staying on the line between the two stars means occupying the 1.st Lagrangian point of the system. That point is not stable, the slightest perturbation would make Jinx drift away into a complicated orbit that would eventually lead to it orbiting much closer to one of the stars, hitting one of them or leaving the system entirely.

Here is an ongoing discussion about the possibility to make a planet in a multisolar system which has no concept of night.

karakris

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Re: A Sort of Problem
« Reply #2 on: February 10, 2013, 07:10:14 AM »
The Planet Jinx would be much closer to Iota A ( the smaller Mass Star ) than to Iota B.

It is just that the rotation of Iota A around Iota B would be at the same rate as the rotation of the Planet Jinx around Iota A.

Is this possible at all ??

Tass

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Re: A Sort of Problem
« Reply #3 on: February 10, 2013, 09:29:16 AM »
The Planet Jinx would be much closer to Iota A ( the smaller Mass Star ) than to Iota B.

It is just that the rotation of Iota A around Iota B would be at the same rate as the rotation of the Planet Jinx around Iota A.

Is this possible at all ??

I just answered that. Jinx orbiting Iota A at the same rate as IotA A orbits Iota B would by definition put Jinx At the 1st Lagrangian point of Iota A-B.

Yes it would be much closer to Iota A because Iota A has a much weaker gravity, thus it has to be closer to get the same orbital period. If you move it even closer to Iota A then it will orbit it faster, not what you want. If you put it further away then it will orbit Iota B instead.

So the short answer is: No. That is not at all possible in newtonian mechanics.

Omnigeek6

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Re: A Sort of Problem
« Reply #4 on: February 10, 2013, 05:57:22 PM »
As has mentioned, this situation will not work. In fact, there is no stable configuration which would give every point on a planet perpetual "daylight."

You could say that in the hypothetical case of a system with a whole bunch of stars, it would be possible to have at least one star in the planet's sky at any given time.

However, multiple star systems are associated with a number called "Hierarchy" as shown here.
http://en.wikipedia.org/wiki/Multiple_star

For a system to be stable, the ratio of the distances of consecutive levels in the mobile diagram must be fairly high; about 5:1 (this is the minimum ratio, aka periapsis distance of more distant body to apsis distance of closer body). Planets also take up a spot in the mobile diagram; planets trying to share orbits with stars will be captured or ejected.
A distant binary or multiple illuminates a planet in pretty much the same way a single star would.
Finally, if a star is too far away, the light it produces can't really be considered "daylight." http://en.wikipedia.org/wiki/Daylight. 1 lux is on the order of magnitude of the full moon, so it's a decent cutoff. This corresponds to a distance of about 500 AU for a sunlike star, and less for K and M class stars.

Basically, this means that even in the best case scenario of a planet orbiting an M-class star in a hierarchy 4 (not counting the planet) system, there will only be 5 stars (or groups of stars) capable of illuminating a planet.

In such an extreme case, parts of a planet could experience periods of hundreds of years where at least one star was always visible (akin to Isaac Asimov's "Nightall") but overall the amount of daylight a planet got would depend on the seasons (very complicated seasons).

unl0cker

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Re: A Sort of Problem
« Reply #5 on: February 11, 2013, 01:00:48 PM »
Can't is a bad nasty word. :P

Well anyway this is my attempt to make light omnipresent in the system.




Download it HERE

For better and smooth view turn Projected Paths on and Trails off
« Last Edit: February 11, 2013, 01:15:03 PM by unl0cker »

karakris

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Re: A Sort of Problem
« Reply #6 on: February 11, 2013, 01:08:36 PM »
Replying to the "perpetual daylight" situation.

I was not looking to get Perpetual Daylight.
The Brown Dwarf will produce a dim light, when the planet turns towards it - a sort of "Red Night" effect.

However - the much brighter White Dwarf will have a very high output of energy / light - and so the "Daylight" will be when it faces "outwards" towards the White Dwarf.
I am not looking for perpetual daylight - just enough light for Life to Form, to Evolve, to Develop, for Mammals, Prosimians, Simians to Evolve.  Enough light for Plants to Evolve and to grow, and enough Light for People to Evolve and develop their Civilisations ( in the Bronze Age ).

Hellpotatoe

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Re: A Sort of Problem
« Reply #7 on: February 11, 2013, 01:12:21 PM »
Replying to the "perpetual daylight" situation.

I was not looking to get Perpetual Daylight.
The Brown Dwarf will produce a dim light, when the planet turns towards it - a sort of "Red Night" effect.

However - the much brighter White Dwarf will have a very high output of energy / light - and so the "Daylight" will be when it faces "outwards" towards the White Dwarf.
I am not looking for perpetual daylight - just enough light for Life to Form, to Evolve, to Develop, for Mammals, Prosimians, Simians to Evolve.  Enough light for Plants to Evolve and to grow, and enough Light for People to Evolve and develop their Civilisations ( in the Bronze Age ).

Life like the Earth one. Because life can be VERY, but VERY different of the Earth one...

unl0cker

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Re: A Sort of Problem
« Reply #8 on: February 11, 2013, 01:20:42 PM »
I've tried that, I mean L1, for like 3 hours! Not a chance.  ;)

You'll have to go with another system config. But it might be possible to be lid most of the time, as shown above.

Addressing your multi-luminosity problem, you either can put Jinx closer, and orbit B. Will not be much effective as at some point both stars will be in one side of Jinx. Or place a less massive than B star far away and make B it's parent, with Jinx still orbiting A.

Or... Jinx, C and A all orbiting B. This is another option.

« Last Edit: February 11, 2013, 01:57:11 PM by unl0cker »

unl0cker

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Re: A Sort of Problem
« Reply #9 on: February 11, 2013, 01:49:40 PM »
Something like this:

System 1 is: J on A, A on B, C on B
System 2 is: J on B, A on B, C on B
System 3 is: J on B, A on B, B on C


I might build over this.  8)
« Last Edit: February 11, 2013, 02:11:56 PM by unl0cker »

Omnigeek6

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Re: A Sort of Problem
« Reply #10 on: February 11, 2013, 10:45:25 PM »
Replying to the "perpetual daylight" situation.

I was not looking to get Perpetual Daylight.
The Brown Dwarf will produce a dim light, when the planet turns towards it - a sort of "Red Night" effect.

However - the much brighter White Dwarf will have a very high output of energy / light - and so the "Daylight" will be when it faces "outwards" towards the White Dwarf.
I am not looking for perpetual daylight - just enough light for Life to Form, to Evolve, to Develop, for Mammals, Prosimians, Simians to Evolve.  Enough light for Plants to Evolve and to grow, and enough Light for People to Evolve and develop their Civilisations ( in the Bronze Age ).


If your planet is receiving most of its radiation from a white dwarf, there's a problem. White dwarfs have a very small radius, so they're also very dim relative to their surface temperatures. To support a habitable zone, a white dwarf needs to have a very high surface temperature, which also means that it must emit a large proportion of ultraviolet and x-ray light. This doesn't preclude habitability, but it does mean that any life that does arise won't be all that earthlike. Also, the HZ of a white dwarf would be close enough in that a planet or brown dwarf orbiting in the HZ would be tidally locked. As a consequence any planet orbiting the brown dwarf would have to orbit faster than its parent rotated, resulting in tidal braking of the planet which would cause it to spiral in and be destroyed.


karakris

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Re: A Sort of Problem
« Reply #11 on: February 13, 2013, 09:11:25 AM »
THanks Everyone - I am just gonna have to leave it as one of those FICTIONAL Things.

This is in a Sci Fi Game - so this will have to be one of the Fictions in the Game.