beecee Posted August 7, 2019 Posted August 7, 2019 https://www.sciencealert.com/astronomers-have-found-a-record-breaking-star-that-s-nearly-as-old-as-the-universe Astronomers Have Found a Record-Breaking Star That's Nearly as Old as The Universe MICHELLE STARR 5 AUG 2019 Another ancient star has been found lurking in the Milky Way. Around 35,000 light-years away, a red giant star named SMSS J160540.18–144323.1 was found to have the lowest iron levels of any star yet analysed in the galaxy. This means that it's one of the oldest stars in the Universe, probably belonging to the second generation of stars after the Universe burst into existence 13.8 billion years ago. "This incredibly anaemic star, which likely formed just a few hundred million years after the Big Bang, has iron levels 1.5 million times lower than that of the Sun," explained astronomer Thomas Nordlander of the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions and the Australian National University. "That's like one drop of water in an Olympic swimming pool." And that's how we can tell how old the star is, because the very early Universe had no metals at all. The first stars were made up primarily of hydrogen and helium, and were thought to be very massive, very hot, and very short-lived. These stars are called Population III, and we've never seen them. more at link..... the paper: https://academic.oup.com/mnrasl/article-abstract/488/1/L109/5533336?redirectedFrom=fulltext The lowest detected stellar Fe abundance: the halo star SMSS J160540.18−144323.1: ABSTRACT: We report the discovery of SMSS J160540.18−144323.1, a new ultra metal-poor halo star discovered with the SkyMapper telescope. We measure [Fe/H]=−6.2±0.2[Fe/H]=−6.2±0.2 (1D LTE), the lowest ever detected abundance of iron in a star. The star is strongly carbon-enhanced, [C/Fe]=3.9±0.2[C/Fe]=3.9±0.2, while other abundances are compatible with an α-enhanced solar-like pattern with [Ca/Fe]=0.4±0.2[Ca/Fe]=0.4±0.2, [Mg/Fe]=0.6±0.2[Mg/Fe]=0.6±0.2, [Ti/Fe]=0.8±0.2[Ti/Fe]=0.8±0.2, and no significant s- or r-process enrichment, [Sr/Fe]<0.2[Sr/Fe]<0.2 and [Ba/Fe]<1.0[Ba/Fe]<1.0 (3σ limits). Population III stars exploding as fallback supernovae may explain both the strong carbon enhancement and the apparent lack of enhancement of odd-Z and neutron-capture element abundances. Grids of supernova models computed for metal-free progenitor stars yield good matches for stars of about 10M⊙10M⊙ imparting a low kinetic energy on the supernova ejecta, while models for stars more massive than roughly 20M⊙20M⊙ are incompatible with the observed abundance pattern.
et pet Posted August 7, 2019 Posted August 7, 2019 (edited) Have you ever heard of or researched the star that is Officially named HD 140283, that many of us astronomers have nicknamed the "Methuselah" star? It has been known as one of "oldest" stars discovered for some time now(pun intended!) and has been studied quite heavily in the last few decades. It is easily researched on the internet if you like. The following is from a few years back written by Dan Levesque and published on Death by Cosmos : https://deathbycosmos.com/methuselah-star/ " WHAT WE KNOW ABOUT HD 140283 Mainstream cosmological models theorize that the first Population II stars didn't form until several hundred million years after the big bang. But HD 140283 presents us with a unique challenge—it appears to pre-date the big bang by about half a billion years. Initial observations had estimated Methuselah to be around 16 billion years old, plus or minus two billion years. In order to resolve this apparent discrepancy with the age of the universe, astrophysicists employed the Hubble Space Telescope to look at HD 140283 with far greater accuracy than any Earth-based telescopes were able to do. With the data gathered from Hubble, astrophysicists published, astrophysicists published a more accurate estimate of Methuselah's age: 14.46 billion years, plus or minus 800 million years. At the lower range of this uncertainty value, HD 140283 could be as young as 13.66 billion years old—which means that it would have formed just 160 million years after the big bang. Unfortunately, that timeline doesn't fit our cosmological models. In a recent study, astronomers using ESA's Planck Satellite determined that the first light from the earliest star formation likely happened 560 million years after the big bang. This means that, while our observations of HD 140283 suggest that it could have formed as early as 13.66 billion years ago, our observations of the cosmic microwave background of the universe suggest that the earliest stars didn't form until 13.26 billion years ago. The numbers simply don't add up. In a follow-up study, astrophysicists analyzed dating methodology by cross-referencing data from Methuselah with other observations of Population II stars that are 10+ billion years old (though none of these conflict with the apparent age of the universe). Upon refinement, astrophysicists published a new paper with an even more precise age for HD 140283: 14.27 billion years, plus or minus 380 million years. Here, the uncertainty was attributed primarily to distance-related precision alone. Having failed to 'solve' the problem, the researchers stated that: The most likely explanations for these difficulties, which would impact our results for the other subgiants as well, are (i) the absolute oxygen abundance that we have determined is too low, (ii) the adopted temperature is too low, (iii) the isochrone Teff scale is too high, or some combination of these possibilities. Alternatively, it remains a remote possibility that HD 140283 truly is older than 14 [billion years], and that current estimates of the age of the universe are too low. Clearly, something here is amiss. WHAT WE DO AND DO NOT KNOW By definition, the process of science can never reveal objective truths about the universe. Every new discovery really only tells us how things appear to be to us, not how things really are. This means that every observation is subject to interpretation. So here are a few possible interpretations of our observation of HD 140283: POSSIBILITY #1: One or more of our observations could be wrong. The laws of physics are being refined and expanded upon all the time, and this gradual evolution of theory does tend to make past theories seem silly. For example, less than a century ago, most astronomers though that the Milky Way galaxy was the only galaxy in the whole universe—now, recent estimates show there could be as many as 2 trillion galaxies in the observable universe. Because of this tendency towards increased knowledge and more accurate theories, scientists are generally really careful. Astronomy is a slow and methodical science by necessity; in many cases, astronomers must literally wait for stars to align in order to collect the data they're after. It's unlikely that any of these observations are wrong, but there remains the possibility that the very act of observation and analysis may be missing some important information. POSSIBILITY #2: Our models of cosmic evolution could be wrong. This is perhaps the most likely culprit, though it would also come as a shock to the scientific community—as has every such paradigm shift that's ever happened. The problem with this possibility is that we don't even know what we don't yet know. There's the implication that something is missing from our physics models (though something is always missing), but we can't grasp what that might be—if we could, then it probably wouldn't be missing. The solution to this one is just a function of time. In due time, it may turn out that our observations were correct, but that our assumptions about the age of the universe or the way in which the first stars formed were incorrect. Or, it may turn out to be a mixture of both. Either way, all we can do is wait and, in the meantime, admit that we just don't know. POSSIBILITY #3: The laws of physics may have changed over time. Shortly after the big bang, the universe looked unrecognizable compared to the cosmos of today—could its physical laws also have been different? Evidence has gone both ways: some observations seem to confirm that the same physical laws existed 10+ billion years ago as exist today, while others show quite the opposite. But would it be so naive to think that we should spend more time thinking about how the physical laws got the way they are in the first place? Acclaimed physicist Richard Feynman takes up this line of thought in the following video, beginning at 7:53 When considering the current state of physics, Feynman states: "It's as though we're doing a Chess game again, and we're working on the rules but we're not worrying about how the pieces are supposed to be setup on the board in the first place." He then goes on to pose a very profound question: could the laws of physics also evolve over time? "It's interesting that in many other sciences, there's a historical question. Like in Geology, they question 'how did the Earth evolve to the present condition?' In Biology, 'how did the various species evolve to get to be the way they are?' But the one field which has not admitted any evolutionary question is Physics. 'Here are the laws,' we say. 'Here are the laws, today'. How did they get that way in time? We don't even think of it that way. We think of, well, that was that way forever." " There is more at : https://deathbycosmos.com/methuselah-star/ Edited August 7, 2019 by et pet 1
beecee Posted August 8, 2019 Author Posted August 8, 2019 (edited) Obviously no star is older then the BB and the universe. The BB of course has itsef been subject to increasing precisions as to how far back it occurred. When I was as kid it was 15 billion years...that has been refined somewhat to 13.83 billion years. The error range with regards to distance and age and methodologies used in measuring distances of stars is also open to refinement...... https://www.space.com/20112-oldest-known-star-universe.html Scientists have known about HD 140283 for more than 100 years, since it cruises across the sky at a relatively rapid clip. The star moves at about 800,000 mph (1.3 million km/h) and covers the width of the full moon in the sky every 1,500 years or so, researchers said. The star is just passing through the Earth's neck of the galactic woods and will eventually rocket back out to the Milky Way's halo, a population of ancient stars that surrounds the galaxy's familiar spiral disk. The Methuselah star, which is just now bloating into a red giant, was probably born in a dwarf galaxy that the nascent Milky Way gobbled up more than 12 billion years ago, researchers said. The star's long, looping orbit is likely a residue of that dramatic act of cannibalism. Distance makes the difference Hubble's measurements allowed the astronomers to refine the distance to HD 140283 using the principle of parallax, in which a change in an observers' position — in this case, Hubble's varying position in Earth orbit — translates into a shift in the apparent position of an object. They found that Methuselah lies 190.1 light-years away. With the star's distance known more precisely, the team was able to work out Methuselah's intrinsic brightness, a necessity for determining its age. The scientists also applied current theory to learn more about the Methuselah star's burn rate, composition and internal structure, which also shed light on its likely age. For example, HD 140283 has a relatively high oxygen-to-iron ratio, which brings the star's age down from some of the earlier predictions, researchers said. In the end, the astronomers estimated that HD 140283 was born 14.5 billion years ago, plus or minus 800 million years. Further observations could help bring the Methuselah star's age down even further, making it unequivocally younger than the universe, researchers said. <<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Add that to the fact that the universe's age as I mentioned previously, also has an error range of about 800 million years, and the so called mystery diminishes somewhat. And of course it also would bring Einstein's GR into question, one of the 20th century's greatest models and highly successful. Perhaps as the original article mentions, gravitational waves may bring these margins for errors down further. In the end, the paradox will be shown, not to be a paradox, one way or the other. Edited August 8, 2019 by beecee
beecee Posted August 8, 2019 Author Posted August 8, 2019 Another Interesting article..... https://www.eso.org/public/news/eso1815/ ALMA and VLT Find Evidence for Stars Forming Just 250 Million Years After Big Bang Astronomers have used observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and ESO’s Very Large Telescope (VLT) to determine that star formation in the very distant galaxy MACS1149-JD1 started at an unexpectedly early stage, only 250 million years after the Big Bang. This discovery also represents the most distant oxygen ever detected in the Universe and the most distant galaxy ever observed by ALMA or the VLT. The results will appear in the journal Nature on 17 May 2018. the paper: https://www.eso.org/public/archives/releases/sciencepapers/eso1815/eso1815a.pdf A fundamental quest of modern astronomy is to locate the earliest galaxies and study how they influenced the intergalactic medium a few hundred million years after the Big Bang1–3 . The abundance of star-forming galaxies is known to decline4, 5 from redshifts of about 6 to 10, but a key question is the extent of star formation at even earlier times, corresponding to the period when the first galaxies might have emerged. Here we present spectroscopic observations of MACS1149-JD16 , a gravitationally lensed galaxy observed when the Universe was less than four per cent of its present age. We detect an emission line of doubly ionized oxygen at a redshift of 9.1096±0.0006, with an uncertainty of one standard deviation. This precisely determined redshift indicates that the red rest-frame optical colour arises from a dominant stellar component that formed about 250 million years after the Big Bang, corresponding to a redshift of about 15. Our results indicate the it may be possible to detect such early episodes of star formation in similar galaxies with future telescopes.
et pet Posted August 9, 2019 Posted August 9, 2019 On 8/8/2019 at 12:13 AM, beecee said: Add that to the fact that the universe's age as I mentioned previously, also has an error range of about 800 million years, and the so called mystery diminishes somewhat. And of course it also would bring Einstein's GR into question, one of the 20th century's greatest models and highly successful. Perhaps as the original article mentions, gravitational waves may bring these margins for errors down further. In the end, the paradox will be shown, not to be a paradox, one way or the other. Yes, like it says in the article : https://www.space.com/20112-oldest-known-star-universe.html , clearly something is amiss. What are your thoughts on Possibility #1, #2 or #3?
Curious layman Posted August 9, 2019 Posted August 9, 2019 On 8/8/2019 at 7:49 AM, beecee said: Another Interesting article..... https://www.eso.org/public/news/eso1815/ ALMA and VLT Find Evidence for Stars Forming Just 250 Million Years After Big Bang Astronomers have used observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and ESO’s Very Large Telescope (VLT) to determine that star formation in the very distant galaxy MACS1149-JD1 started at an unexpectedly early stage, only 250 million years after the Big Bang. This discovery also represents the most distant oxygen ever detected in the Universe and the most distant galaxy ever observed by ALMA or the VLT. The results will appear in the journal Nature on 17 May 2018. the paper: https://www.eso.org/public/archives/releases/sciencepapers/eso1815/eso1815a.pdf A fundamental quest of modern astronomy is to locate the earliest galaxies and study how they influenced the intergalactic medium a few hundred million years after the Big Bang1–3 . The abundance of star-forming galaxies is known to decline4, 5 from redshifts of about 6 to 10, but a key question is the extent of star formation at even earlier times, corresponding to the period when the first galaxies might have emerged. Here we present spectroscopic observations of MACS1149-JD16 , a gravitationally lensed galaxy observed when the Universe was less than four per cent of its present age. We detect an emission line of doubly ionized oxygen at a redshift of 9.1096±0.0006, with an uncertainty of one standard deviation. This precisely determined redshift indicates that the red rest-frame optical colour arises from a dominant stellar component that formed about 250 million years after the Big Bang, corresponding to a redshift of about 15. Our results indicate the it may be possible to detect such early episodes of star formation in similar galaxies with future telescopes. Maybe in future they could use this~ Space Telescope: abstract...Astronomer David Kipping of Colombia University has worked out that a 1-meter space telescope, positioned beyond the moon, could use the focusing power of the ring of the atmosphere seen around the edge of the planet to amplify the brightness of dim objects by tens of thousands of times. More at link.... Sound exciting to me, there's still alot of issues to solve but it sounds really promising.
beecee Posted August 9, 2019 Author Posted August 9, 2019 (edited) 10 hours ago, et pet said: Yes, like it says in the article : https://www.space.com/20112-oldest-known-star-universe.html , clearly something is amiss. What are your thoughts on Possibility #1, #2 or #3? Of course all possibilities need to be considered, but just as obviously the overwhelmingly likelyhood that measurement methodologies, and aging processes methods and entailed precisions, appear to be the problem, shown of course by the fact that the so called "discrepancy" is continually being diminished as already shown. 9 hours ago, Curious layman said: Maybe in future they could use this~ Space Telescope: abstract...Astronomer David Kipping of Colombia University has worked out that a 1-meter space telescope, positioned beyond the moon, could use the focusing power of the ring of the atmosphere seen around the edge of the planet to amplify the brightness of dim objects by tens of thousands of times. More at link.... Sound exciting to me, there's still alot of issues to solve but it sounds really promising. Great stuff! And coupled with the SKA, LISA, and the JWST, the future would appear to be quite exciting. Edited August 9, 2019 by beecee
et pet Posted August 9, 2019 Posted August 9, 2019 5 minutes ago, beecee said: Of course all possibilities need to be considered, but just as obviously the overwhelmingly likelyhood that measurement methodologies, and aging processes methods and entailed precisions, appear to be the problem, that "discrepancy"of course is continually being diminished as already shown. The above does not seem to relate to the 3 Possibilities Listed in the Link : https://deathbycosmos.com/methuselah-star/ , (I posted the wrong Link in my previous Post!) Once again, may I inquire, What are your thoughts on : "Clearly, something here is amiss. WHAT WE DO AND DO NOT KNOW By definition, the process of science can never reveal objective truths about the universe. Every new discovery really only tells us how things appear to be to us, not how things really are. This means that every observation is subject to interpretation. So here are a few possible interpretations of our observation of HD 140283: Possibility #1 - One or more of our observations could be wrong. Possibility #2 - Our models of cosmic evolution could be wrong. Possibility #3 - The laws of physics may have changed over time. " - https://deathbycosmos.com/methuselah-star/
beecee Posted August 9, 2019 Author Posted August 9, 2019 (edited) 20 minutes ago, et pet said: The above does not seem to relate to the 3 Possibilities Listed in the Link : https://deathbycosmos.com/methuselah-star/ , (I posted the wrong Link in my previous Post!) Once again, may I inquire, What are your thoughts on : "Clearly, something here is amiss. WHAT WE DO AND DO NOT KNOW By definition, the process of science can never reveal objective truths about the universe. Every new discovery really only tells us how things appear to be to us, not how things really are. This means that every observation is subject to interpretation. So here are a few possible interpretations of our observation of HD 140283: Possibility #1 - One or more of our observations could be wrong. Possibility #2 - Our models of cosmic evolution could be wrong. Possibility #3 - The laws of physics may have changed over time. " - https://deathbycosmos.com/methuselah-star/ I repeat..... Of course all possibilities need to be considered, but just as obviously the overwhelmingly likelyhood that measurement methodologies, and aging processes methods and entailed precisions, appear to be the problem, and that is shown by the fact that the so called "discrepancy" is continually being diminished as already shown. 20 minutes ago, et pet said: "Clearly, something here is amiss. As shown in earlier posts, what seems to be amiss, is most probably simply a result of inaccuracies, error bars, and lack of precision...all of which are continued to be refined, resulting in what seems to be amiss, to be ever increasingly less and less amiss. Edited August 9, 2019 by beecee
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