So in discussing astronomy with a friend who was asking about the limited stuff I know about astronomy (from a 101-102 astronomy class many moons ago and a “Life on Other Worlds” class three years ago), I suddenly had a thought:
Did the previous star that made up our system leave behind a red dwarf? If so wheres? Or a neutron star? Or was it a supernova or hypernova or something that didn’t leave anything behind?
Or did the previous star’s reminants drift off or did our dust cloud drift off?
I know there is some random “Nemesis” or “Planet X from Beyond Thunderdome” theories. I’m interested in knowing the actual possibilities.
I’m not quite clear on what you mean by “the previous star that made up our system.” The current models of stellar evolution (as far as I know) say that stars (including the sun) are formed in “giant molecular clouds” (GMCs), which are essentially dense regions of the interstellar medium that are collapsing under their own gravity. More details available here.
It’s possible that you’re referring to the fact that the heavy metals (i.e. anything heavier than helium) that are present in the solar system were created in supernovas that occurred before the Sun formed. But I doubt that any one star provided all (or even most) of these metals; more likely, the Solar System contains such atoms from all over the galaxy. If this isn’t what you mean, though, feel free to clarify.
I’m not an astronomer, but I follow that stuff a little bit and I’m unaware of any credible theory involving the sun & solar system as the offspring of a prior, individual star. That the sun is composed of matter that had served time as the components of other stars generically, yes.
Is there evidence that we came from a previous star and if so, where is that star’s remains (red dwarf, neutron star, black hole, white dwarf, etc.)?
If not, well I guess that answers my question also but would lead me to:
Does the Sun have sister stars out and about from said nebula or was it too small?
Yes. Most stars in the disk of a galaxy are formed in groups called open clusters, about a thousand at a time. Open clusters are somewhat loosly bound together, and the stars in them can drift apart over time. The Sun’s sisters have drifted apart to the point that it’s debateable whether we should still be considered a cluster, but at least some of the stars are still identifiable. If I recall correctlly, the family includes most of the Big Dipper and Alpha Centauri, among others. Interestingly, the next-closest star after Alpha Centauri, a red dwarf called Barnard’s Star, is not a sister to the Sun, but a fast-moving halo star which just happens to currently be passing through our vicinity right now.
Incidentally, to clear up a minor point in the OP, stars don’t become red dwarfs when they die. They become white dwarfs, and eventually, as the white dwarf cools down, what’s called a black dwarf (really the same thing, just no longer shining). Or, if they’re massive enough, neutron stars or black holes. A red dwarf is a star which is still on the Main Sequence (in the main part of its life, and still burning hydrogen) which is just very small (and therefore cool and dim).
The metal content of the sun tells us that it formed out of a nebula that contained material from earlier nova supernova. However, that was around 5 billion years ago, and the sun does a complete orbit of the galactic center ever 230 million or so years. That’s given supernova remnants, or stars formed from the same cloud plenty of time to disperse.
You don’t recall correctly. AFAIK, we don’t know of any star that was part of the original cluster the sun was born in. Most of the Big Dipper plus Sirius make up a loose cluster. Such loose clusters are usually called associations.
Open clusters that stars are born in evaporate as various stars in them attain escape velocity through encounters with other stars in the cluster. Eventually all the stars that made up a cluster will be strung out around the galaxy at about the same distance from the center as the original cluster. This is what happened to the cluster the sun was born in.
BTW, Alpha Centauri is either slightly older or considerably older depending on whether or not it has a convecting core (source: SolStation). In either case, that precludes it from being in the same cluster the sun was in.
I thought Red Dwarf just left a bunch of Smegheads; Lister, Rimmer, Kryten and Cat.
But, SD user ‘smeghead’ most likely did not came from such sources.
I will probably soon get corrected on this, but as I have never heard of the term “smeghead” out side of the great show… I think this is where he got it from as well.
OK, so the Sun was likely formed, along with some other stars, from a big cloud of material left over from previous supernova(e). Was this one big freakin’ supernova, whose remnants formed several stars, or was it several of them in the same region?
Was it similar to what the Great Nebula in Orion is now? Where did all that material come from? And why is it in a fairly compact cloud, instead of being distributed over a large swath of our galaxy?
I recall reading the same thing as Chronos mentioned, and another one which will follow below, but both were purely speculation as to what association the Sun might have at one time been a part of. The alternative to Chronos’s thing is that the Sun, Alpha Centauri, and one other relative-nearby star (identity not remembered) were actually outlying members of the Hyades, quite far along in the process of ejection from that association.
Who comes up with these fanciful speculations, I wonder?
One of the important things about open star clusters is that the stars in each all formed at the same time. So any star that was originally in the same cluster as the sun will have an age of about 4.6 billion years. The Hyades have an age of something like 650 million years. Way too young for the sun to be part of. Ditto for the Pleiades, which I believe is even younger.
The material the solar system came from was cycled through a number of stars. Much of it went through more than one star. Well, some of the hydrogen and helium may possibly have not been in a star previously, but the heavier elements definitely were.
One possibility is that the OP is refering to a supernova that was hypothesized as starting the collapse of the solar nebula. I’m not sure if this is still a required part of the formation of the sun. AIUI, the reason that they thought there was such a supernova was certain radionuclides seemed to have been created about the same time as the sun. However, a while back someone came up with a mechanism for nucleosynthesis in the planetary disk which may have formed these radioactives.
For clarity, it should be noted that Alderbaran, the nearest bright star - and part of the Hyades - is NOT moving with the rest of that open cluster. Instead, the bright star, Capella, in the nearby constellation Auriga (The Charioteer) is moving with that open cluster, IIRC.
