Dual Suns

[ThatSpaceBoy]

What if the Earth's star was two stars? Like, the kind that orbits each other. If there were that in the middle of the solar system, what would conditions on Earth be like? Would life as we know it be able to exist?

 

[Wolfshadw]

I think it would depend on the type of stars. If you're thinking what if two of our sized stars orbited each other at the center of our solar system, then I would think that the "Goldilocks Zone" that makes conditions for life as we know it possible, would be pushed further out. If Earth's orbit were pushed out as well, then I think it's a good possibility that life as we know it (assuming nothing else changed) would still exist.

-Wolf sends

 

[rod]

FYI. This exoplanet site shows the number of host stars reported in the system, https://exoplanetarchive.ipac.caltech.edu/index.html

Currently 4383 exoplanets are reported. 439 are reported with 2-4 host stars, multiple star systems, 384 are in binary systems. 55 Cnc is a good place to start as a binary system reporting 5 exoplanets orbiting there. However, stars with the largest number of exoplanets orbiting like 7 or 8 are single host star systems reported. Example, TRAPPIST-1, KOI-351, Kepler-90 i. The total number of binary star systems reported in the exoplanet site is 288 that have exoplanets.

 

[Hetherington]

The “binary suns” term means two Sun-like stars (i.e., twin Suns) orbiting each other, in a binary system. Unlike the stars in Star Wars's Tatooine system, our Sun is not in a binary system.

 

[Catastrophe]

OP, what, in post #2, left anything answered?

Cat

 

[Helio]

Orbital stability is problematic especially over billions of years for HZ exoplanets in a close binary. Distant orbiting binaries are less problematic. [Proxima Centauri b should have little problem with the other two stars in the system.]

There is a gravitational pulsing effect in a close binary. This may, perhaps, only cause migration of the planet. But I think that in most of these cases the planet would not have had much time in the HZ as is necessary for life.

[I missed the OP was over a year ago. ]

 

[Catastrophe]

I am getting more unhappy, as in other threads in the last two minutes.
Now spacetime is pulling together because of gravity?

Cat

 

[Helio]

I am getting more unhappy, as in other threads in the last two minutes.
Now spacetime is pulling together because of gravity?

I'm unclear what you mean?

Another way to see it is that the binary creates gravity waves, and objects move (slight orbit shifts) when these waves continually impact a planet's orbit. [I think I'm right.]

 

[Catastrophe]

Like Gravity thread. You said spacetime thickens (?).

 

[Helio]

Like Gravity thread. You said spacetime thickens (?).

I was being facetious with the speculative nature of space expansion. I have only subjective opinions. There are no objective arguments for how space expands so far, I expect. DE is just a label, not an explanation.

 

[Catastrophe]

Helio, I am beginning to have more doubts about expansion. I am happy in principle about BB, but some issues are emerging about closer to origin (galaxies approaching, and now (separately) about double stars). This concept of jiggling around with spacetime worries me.

Cat

 

[Catastrophe]

Have you come across Sten Odenwald? He writes on many subjects me including Astrophysics, Quantum Theory, et cetera. Well worth a Google (and a read).

Cat

 

[Helio]

Helio, I am beginning to have more doubts about expansion. I am happy in principle about BB, but some issues are emerging about closer to origin (galaxies approaching, and now (separately) about double stars). This concept of jiggling around with spacetime worries me.

The only galaxies approaching us are ones nearby. There are no known distant galaxies that do not fit the Hubble-Lemaitre constant, AFAIK. If any galaxy did not fit appropriately in this model, it would be big news. It's likely that only a number of our Local Group of galaxies have the only blueshifts (e.g. Andromeda).

When black holes merge, incredibly powerful gravitational waves are created. But these waves occur as they orbit violently during the moment just before they merge, not after. An audio "chirp" sound can be heard when the frequencies are matched into sound waves. The different "chirp" sounds say a lot about the merger.

Smaller waves propagate the farther apart they are. Less massive objects that orbit one another produce waves as well, but with much smaller amplitudes.

 

[Catastrophe]

Helio, as I have said many times, my concerns are nearby where galaxies are approaching. As I mentioned, this is s different part of the curve (or line). It is obvious from the plots that (as we know, anyway) there are plots of negative receding velocity. In this part of the graph, Hubble's "Law" is not being obeyed. It does invalidate the upper regions. It is like a phase diagram. At higher T the molecules jump around (galaxies separate), at lower T higher P molecules come together and condense (galaxies closer together). There is simply a different relationship and a change jn the graph.. A dotted line does not cut it. It just has to be recognised that HL applies above certain parameters but not below.

Cat

 

[Catastrophe]

I think that this belongs here


Dual Suns | Space.com Forums

Cat

 

[Helio]

It just has to be recognised that HL applies above certain parameters but not below.

I would think that it does apply to the Local Group, but the result is not that noticeable.

Perhaps we can test this idea. What if we look at the radial motions of the Local Group and see if there is anything in this result that might guide us....

Here is what I found, then, addtionally, adjusted for H-L constant...


The Local Group (rit.edu)

The bottom yellow highlight boxes tell a story, I think.

The actual motion is an average of about 27kps away from us, but when we remove the H-L expansion component, we see that the net motion is towards us at close to this same amount, surprisingly.

I'm guessing that the expansion is having an effect on the Local Group to have them, on average, be moving away from our concentrated mass of all our galaxies. I would also assume that without the H-L rate, that they would have a net inward (blueshift) value, which is what we seem to have. This ignores, admittedly, some serious astrophysics to do it right, but sometimes a crude approach gets us playing on the same ball field, at least.

 

[Catastrophe]

OK, I am reaching for my graph paper. I shall probably be "around" but pretty quiet for a while.

What is the actual corresponding velocity and why? I want the actual H-L graph same velocity measure as H-L for accurate comparison.

Cat

 

[Helio]

Here is a scatter graph, FWIW, for the existing data (presumably with H-L expansion). Y-axis is kps and X-axis is 1000 lightyear units. [Not the best I can do in graph quality, but I'm out of time.]



Here is the result after removing 70 kps/Mpc....

 

[Catastrophe]

I don't understand HL Velocity and Adjusted Velocity. Which is the actual recessional (or opposite) velocity. I want a direct comparison with the usual recessional velovity / distance graph.

Cat

 

[billslugg]

Andromeda galaxy is approaching Milky Way at 402,000 km/hr.
Distance is 2.5 million light years.
Parsec is 3.26 light years
Andromeda is .77 megaparsecs away from us
Hubble constant is 70 km/sec/megaparsec
Andromeda is receding due to space expansion at a rate of 54 km/sec
Andromeda net movement is towards us at 112 km/sec due to gravitational attraction.
Both the expansion of space and the attraction of gravity have a significant effect on the rate at which the two galaxies move relative to each other.

 

[Helio]

Andromeda is receding due to space expansion at a rate of 54 km/sec
Andromeda net movement is towards us at 112 km/sec due to gravitational attraction.
Both the expansion of space and the attraction of gravity have a significant effect on the rate at which the two galaxies move relative to each other.

Yes, this is how I see things move in relation to both expansion and gravity. The two can be treated as separate vector forces.

It's similar to a boat moving on the Ohio river, if it isn't moving under its own power or being pushed or pulled by a tug, it simply moves at the rate of the water flow. Gravity is the tug boat, of course.

Perhaps this is mainstream (pun unintended), but is it?

 

[Helio]

I don't understand HL Velocity and Adjusted Velocity. Which is the actual recessional (or opposite) velocity. I want a direct comparison with the usual recessional velovity / distance graph.

The first graph is the measured radial velocity (see data link). The second simply subtracts the Hubble flow (H-L constant) of 70kps per 3.26M lightyears of distance. [Hmmm, did they change "Hubble Flow "to "Hubble-Lemaitre Flow"?)

Using the Ohio river analogy, the first graph are the observed boat speeds measured from an island in the middle of the river. The second are the boat speeds when someone closes all the gates downstream stopping the river's flow.

 

[Catastrophe]

Ahh! I want to plot exactly the same as the usual graph. Is that (recessive) velocity in the table. The other (non adjusted?) velocities are all positive.
Thank you for providing the table, but I am a little confused.

Cat

 

[Helio]

Ahh! I want to plot exactly the same as the usual graph. Is that (recessive) velocity in the table.

The negative values for RV are for velocities towards Earth, positive are the recessional velocities.

The other (non adjusted?) velocities are all positive.

There are both neg. and pos. values for vel. So I'm not clear what you are saying.

Does that help?

 

[Catastrophe]

https://imgur.com/a/vvPrKGo

View: https://imgur.com/a/vvPrKGo


Which should I use to plot actual velocity (+ or -) against distance, as in the usual graph, please? Is it the radial velocity? Is that the correct one?

Cat