Sigma1 Taurus

[Angry Space Goat]

I have an Earth-like planet in orbit around Sigma1 Taurus. I'm concerned about whether or not we could actually live on this planet with life being relatively similar to how it is on Earth.

Two main problems - one, it's a binary star system (Sig2 Tau is 0.3 light years away), and two, I don't know what's over there - like some black hole, or nuetron star.

So my question is, firstly, with the mechanics of binary star systems as such, would Sig2 Tau come too close and fry my planet? Here are the relevant specs on each from Celestia:

Sig1 Tau
Abs mag: 1.74
Luminosity: 17.2x sun
Class: AV4
Surface temp: 8,460 K
Radius: 1.96 Rsun

Sig2 Tau
Distance: 0.32190 ly
Abs mag: 1.33
Luminosity: 25.2x Sun
Class: A5 V
Surface temp: 8,200 K
Radius 2.50 Rsun

My second question is, does anyone here know of any celestial mechanisms within the area that would disallow this planet existing or humans existing on it? Sigma1 Taurus is in the Taurus constellation (of course), off just a little to the side of Aldebaran. I've looked into it, but only as far as Google could take me, without much result.

Any help would be appreciated. Thanks.

[Rocket Man]

I have made a terrestial planet orbiting around the both Rigel Kentaurus Stars

>

I don't know what's over there - like some black hole, or nuetron star

Black Holes Have a event horizon. Meaning they have a boundry to there great gravitional pull. But still have an affect to nearby objects. Not sure about nuetrons though.

>

So my question is, firstly, with the mechanics of binary star systems as such, would Sig2 Tau come too close and fry my planet?

It all depends on the distance form the parent star. If you place in orbit too far, Sig2 Tau gravity may steal it. I say a good distance is about 2 AU.

>

My second question is, does anyone here know of any celestial mechanisms within the area that would disallow this planet existing or humans existing on it?

Your planet may exist. Like I said above, Depends on Distance. And for Humans, How close to the star is. Tempture takes affect here. 2 AU is earth-like place to them.

I hoped this helps.
Keep in mind, Celestia doesn't worry about factors like gravity or we'll get stuck in one of Cham's black holes.

[Rocket Man]

Something came to mind,
Instead of the planet's orbit going in between the stars why make the inclination in your .SSC file like 90 degrees, This make it so if it was real, Sig2 Tau has little affect on your planet.

[Angry Space Goat]

Yes, thanks. Very helpful.

[Rocket Man]

What's the point of Knowledge if don't share it?
- Rocket Man

Your Welcome.

[eburacum45]

One thing that springs to mind is the fact that Sigma1 Tauri is a young, short-lived star compared to the Sun; the normal lifetime of an A class star like this is around one billion years, barely enough time for primitive life to become established on the planet (if the history of the Earth is any guide).

So if you want to have a human habitable world around either of these stars you will need to terraform a suitable planet- there would almost certainly be no naturally ocurring Earth-type worlds orbiting A class stars.

On the other hand the companion star Sigma2 Tauri is 0.3 light years away; it should have no effect on the planet at all (apart from interactions between the local Oort clouds, if any)

[Rocket Man]

I never realized that. That a good point though. Only good binary canidates I know is Rigle Kentaurus A & B. but terraforming still will be long process (that's if there any form of water around). This wouldn't be a good planet to terraform

[Dollan]

There are some other good binary candidates out there. One of the top contenders in my book is Eta Cassiopeiae, with a G-type primary and an M-type companion, the orbital range of which leaves plenty of room for a small system, including a habtable world.

...John...

[Angry Space Goat]

I looked around the nearby area and found Theta Taurus, which is also a binary system about 9 light years away from the Sigma Taurus system.

Theta 1 Taurus
Abs mag: 0.41
Luminosity: 58.4x Sun
Class: G7III
Surface temp: 5070 K
Radius: 11.19

Theta 2 Taurus
Distance: 0.25806 ly
Abs mag: -0.02
Luminosity: 87.4x Sun
Class: A7III
Surface temp: 7650 K
Radius 5.24 Rsun

Theta 2 Taurus, though smaller, is still an A type star, and hotter and brighter than its sister star. Also, it's only .2 light years away, as opposed to Sig1/Sig2 Tau, which are only .3.

Would this be a problem?

[Rocket Man]

I don't think so. With the "G" star as your planet's parent star it would seem to be a fine second home.

[Ynjevi]

There are some other good binary candidates out there. One of the top contenders in my book is Eta Cassiopeiae, with a G-type primary and an M-type companion, the orbital range of which leaves plenty of room for a small system, including a habtable world.

Actually Achird (Eta Cas) is G+K system, much like Alpha Centauri. However, they orbit farther apart (70 AU versus 24 AU). Achird A would be a good candidate for hosting Earth-like planets, but unfortunately it is a rather metal-deficient star compared to the Sun.

[ajtribick]

I looked around the nearby area and found Theta Taurus, which is also a binary system about 9 light years away from the Sigma Taurus system.

Theta 1 Taurus
Abs mag: 0.41
Luminosity: 58.4x Sun
Class: G7III
Surface temp: 5070 K
Radius: 11.19

Theta 2 Taurus
Distance: 0.25806 ly
Abs mag: -0.02
Luminosity: 87.4x Sun
Class: A7III
Surface temp: 7650 K
Radius 5.24 Rsun

Theta 2 Taurus, though smaller, is still an A type star, and hotter and brighter than its sister star. Also, it's only .2 light years away, as opposed to Sig1/Sig2 Tau, which are only .3.

Would this be a problem?

The problem is you still have an A type star in the binary system - binary systems are thought to condense out at the same time, so if you've got an A star in the system you've still got a very young system on your hands even if the star you are considering is a G or K star.

In addition both stars are giants (the III in the spectral class means giant, as opposed to main sequence stars at V) as opposed to main sequence dwarfs. The spectral type implies that they formed from massive stars, probably type A and up, so you've got a very young system which is now being roasted by the increase in luminosity of the giant phase.

[Dollan]

Actually Achird (Eta Cas) is G+K system, much like Alpha Centauri. However, they orbit farther apart (70 AU versus 24 AU). Achird A would be a good candidate for hosting Earth-like planets, but unfortunately it is a rather metal-deficient star compared to the Sun.

The metallicity rating, according to Don C. Barry, in some 0.65 that of Sol, well into the range of acceptibility (the cut-off point for terrestrial planets is often listed as 0.4 that of Sol, although I have seen that figure as low as 0.3).

...John...

[Angry Space Goat]

What I'm looking for is a star slightly larger than Sol with a nearby star, under four light years away. I would like at least one of the stars to be part of a constellation.

I've found the best candidate system so far; Epsilon 1 Lyra and Epsilon 2 Lyra... but there's one problem.

Epsilon 1 Lyra
Abs mag: 1.18
Luminosity: 28.8x Sun
Class: F1 V
Surface temp: 7,050 K
Radius 3.54 Rsun

Epsilon 2 Lrya
Distance: 0.016401 ly
Abs mag: 1.10
Luminosity: 30.9x Sun
Class: A8 V
Surface temp: 7,580 K
Radius: 3.17 Rsun

As you can see, they're very, very close to each other. What would be the scenario between these two - would they orbit each other, or if not, would they perturb the orbits of each other's planets?

[ajtribick]

The stars are separated by ~1000 AU. This is a long way away, so both stars could have stable planetary systems (a quick rule of thumb is that stable orbits around a single star exist out to ~1/3 of the minimum distance between the stars)

The closest distance between the stars depends on the eccentricity of the orbit, and I'm not sure how well the orbit of those stars is known, probably not very well, as the period is likely to be several thousands of years).

You've still got an A star in your system, and what you seem to have missed is that both Epsilon1 and Epsilon2 Lyrae are themselves double stars. The summary you have got has basically treated both double systems as a single star (basically, if we imagine that the light coming from Epsilon1 Lyrae is coming from a single star, what are the properties of that star). Epsilon1 and Epsilon2 probably don't interfere with each other much, the problems are going to come when you deal with Epsilon1 Lyrae A and B, and Epsilon2 Lyrae A and B.

In addition you are going for some short lived stars - I do not know the age of Epsilon Lyrae but it would have to be less than 2 billion years (because you have an A8 dwarf), so without further information there's a high likelihood that you're dealing with a heavy bombardment system again.

[Scorpiove]

As you can see, they're very, very close to each other. What would be the scenario between these two - would they orbit each other, or if not, would they perturb the orbits of each other's planets?

I thought binary meant that its a double star system and so it means that atleast one of hte stars in the system is orbiting the other is this correct? and are you reffering to that or are you reffering to them equally orbiting each other instead of one orbiting the other.

[julesstoop]

They orbit a common barycentre. If the difference in mass between the two stars is big, the barycentre will be close to or even inside the heaviest star. In the example of ?µ-lyrae: the stars are about the same mass, and there barycentre is somewhere half way between them.
Does this answer your question?