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Our sun's theorized progenitor star carries the (proposed) name Coatlicue. Since our sun is thought to be a third generation* star there should be two generations preceding it - and therefore one generation preceding Coatlicue.

Is there a proposed name for Coatlicue's predecessor(s)? If so, that would for example make discussing it or researching it simpler.


* note: third generation, not population III. The sun is in fact a population I or heavy-element-rich star.

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    $\begingroup$ Please note that Coatlicue is not the progenitor star of the Sun as in “from Coatlicue arose the Sun,” but more like “Coatlicue affected the protosolar nebula and made it turn into a star.” The closest comparison I would give is that Coatlicue is not the mother of the Sun (the Sun did not come out of Coatlicue), but more like its father (through “impregnation” of the nebula). $\endgroup$ Aug 28, 2023 at 23:27
  • $\begingroup$ You have misunderstood the meaning of "third generation star". $\endgroup$
    – ProfRob
    Aug 29, 2023 at 7:22

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It's most likely that Coatlicue didn't have an equivalent predecessor. Please bear in mind that we aren't certain that the Sun had such a single progenitor star, but it's a very good hypothesis.

Star formation occurs through gravitational collapse in molecular clouds. As Wikipedia mentions, "the physics of molecular clouds is poorly understood and much debated", so there is an element of speculation in what follows. However, we do have quite reasonable models of the major processes that are consistent with the numerous observations that have been made of these stellar nurseries.

The fundamental process is Jeans instability, which

causes the collapse of interstellar gas clouds and subsequent star formation, named after James Jeans. It occurs when the internal gas pressure is not strong enough to prevent gravitational collapse of a region filled with matter.
[...]
The Jeans instability likely determines when star formation occurs in molecular clouds.

As the cloud collapses it tends to fragment, giving rise to stars of various sizes.

As you mentioned, our Sun's stellar nursery contained gas and dust from thousands of earlier stars (as well as primordial gas from the Big Bang).

As ProfRob said in the linked answer

The material spewed out from supernovae and stellar winds 5-12 billion years ago has had plenty of time to mix throughout the Galaxy before the Sun's birth. Turbulence and shear instabilities, driven by the winds and supernovae from massive stars, should distribute material on galactic-length scales in a billion years or less

Coatlicue was a large star which formed before the Sun, so it's likely that it was one of the earliest stars produced during the collapse process.

In this answer on stellar nurseries ProfRob says

The lifetimes of very massive stars (10-50 Myr) are comparable with the dispersion timescale for young clusters and associations. So massive stars tend to die near where they were born and they will be surrounded by their (more numerous) lower mass siblings. Lower mass stars have long lives and end up dispersing and making up the general population of a galaxy.

The early large stars affect the subsequent collapse process in their neighbourhood through their stellar winds and intense ionising radiation. Pela gives some information and diagrams in this answer on the "Pillars of Creation" in the Eagle Nebula.

So these large stars influence the formation of their siblings while they're still alive. And when they finally explode as a supernova the huge energy and matter release obviously has a big impact.

The formation of Coatlicue itself may have been influenced by winds and radiation from its large siblings, but because it was born early it's unlikely that its birth was triggered by a nearby supernova.


The key evidence for the Coatlicue hypothesis is related to radioactive aluminium-26 (Al-26), which has a half-life of 717,000 years. Aluminium-26 is primarily produced in core-collapse supernova explosions. As detailed in that Wikipedia article, H. C. Urey proposed the heat from Al-26 was highly likely to contribute to the known melting of small planetary bodies in the early Solar System. And if that's true, then there must have been a nearby supernova around the time of the formation of the Solar System.

Essentially all of that Al-26 has decayed by now to its stable daughter isotope magnesium-26 (Mg-26). The magnesium isotope ratios in meteorites are consistent with Urey's hypothesis.

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  • $\begingroup$ And So if our Sun is 3rd generation, it's progenitor will not be 2nd generation (from Arjun's answer) is also correct? $\endgroup$
    – nada
    Aug 30, 2023 at 10:11
  • $\begingroup$ @nada Yes, that's correct. Coatlicue is 3rd generation. It was an older sibling of the Sun, born in the same molecular cloud. $\endgroup$
    – PM 2Ring
    Aug 30, 2023 at 12:04
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Coatlicue is not a 2nd generation/population II star, it is population I itself, just like the Sun. The reason for this is because, the progenitor of Coatlicue is also not a population II star therefore Coatlicue cannot be formed of a SNR of a 2nd generation star, it too was formed from a 3rd generation star. For example the increasing metallicity, caused by stellar nucleosynthesis is actually the Slow Neutron capture process, a form of nucleosynthesis, and as it's name says it does is very slow, so for example if the star has 0.012 metallicity, like G2V Sun, the direct progenitor can't be like 0.09, unless and until it is the fast neutron capture process. Also our Sun's progenitor SNR were many, there was not a single star there were many stars proven by dust isotopes of comets and meteoroids. So if our Sun is 3rd generation, it's progenitor will not be 2nd generation.

As per my knowledge, I don't think that we have a name for the progenitor of Coatlicue, because we don't even know whether it was type la or not or whether it was formed in a Binary system. But sources refer to Tlaltecuhtli i.e Earth monster in Aztec/Nahoa mythology as the progenitor, but we don't have a name for it in Astronomical terms.

Thanks!

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  • $\begingroup$ Is that so? This answer to another question seems to disagree: So that is why I claim the Sun can be classed as a "third generation star" - it contains atoms/nuclei that must have been inside at least two previous stars. $\endgroup$
    – nada
    Aug 28, 2023 at 12:18
  • $\begingroup$ Tlaltecuhtli. Fascinating. What sources did you refer to? $\endgroup$
    – nada
    Aug 28, 2023 at 12:27
  • $\begingroup$ @nada Wikipedia: en.wikipedia.org/wiki/Tlaltecuhtli. Thanks! $\endgroup$
    – Arjun
    Aug 28, 2023 at 12:29
  • $\begingroup$ @nada Yes, it is correct, however the previous 2 stars aren't always 2nd generation stars $\endgroup$
    – Arjun
    Aug 28, 2023 at 12:30

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