NAOJ: Stellar Heavy Metals Can Trace History of Galaxies

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NAOJ: Stellar Heavy Metals Can Trace History of Galaxies

Post by bystander » Sat Jan 11, 2020 4:08 pm

Stellar Heavy Metals Can Trace History of Galaxies
National Astronomical Observatory of Japan | 2020 Jan 09
Astronomers have cataloged signs of 9 heavy metals in the infrared light from supergiant and giant stars. New observations based on this catalog will help researchers to understand how events like binary neutron star mergers have affected the chemical composition and evolution of our own Milky Way Galaxy and other galaxies.

Right after the Big Bang, the Universe contained only hydrogen and helium. Other elements were formed later through nuclear fusion in stars or violent events like supernovae or binary neutron star mergers. However, the details of the various processes and their relative contributions are still poorly understood. Better understanding of the chemical evolution of galaxies is important to understand how the rich element environment of planets like Earth came to be. In particular, metals heavier than nickel can be used to trace violent events such as binary neutron star mergers. ...

Identification of Absorption Lines of Heavy Metals in the
Wavelength Range 0.97–1.32 μm
~ Noriyuki Matsunaga et al
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Stellar Heavy Metals Can Trace History of Guacamole

Post by neufer » Sat Jan 11, 2020 6:43 pm

Art Neuendorffer

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Re: NAOJ: Stellar Heavy Metals Can Trace History of Galaxies

Post by BDanielMayfield » Tue Jan 14, 2020 3:22 pm

Curious as to the identities of the 9 members of this heavy metal band, I drilled down and pulled this from the paper's abstract:
We have detected lines of Zn i, Sr ii, Y ii, Zr i, Ba ii, Sm ii, Eu ii, and Dy ii, in the order of atomic number.
Who the band's 9th member is remains a mystery.
"Happy are the peaceable ... "

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Re: NAOJ: Stellar Heavy Metals Can Trace History of Galaxies

Post by Ann » Tue Jan 14, 2020 4:17 pm

BDanielMayfield wrote:
Tue Jan 14, 2020 3:22 pm
Curious as to the identities of the 9 members of this heavy metal band, I drilled down and pulled this from the paper's abstract:
We have detected lines of Zn i, Sr ii, Y ii, Zr i, Ba ii, Sm ii, Eu ii, and Dy ii, in the order of atomic number.
Who the band's 9th member is remains a mystery.
Who's number 9? Where's number 9?
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"Humph!"

Post by neufer » Tue Jan 14, 2020 4:52 pm

Ann wrote:
Tue Jan 14, 2020 4:17 pm
BDanielMayfield wrote:
Tue Jan 14, 2020 3:22 pm

Curious as to the identities of the 9 members of this heavy metal band:
We have detected lines of Zn i, Sr ii, Y ii, Zr i, Ba ii, Sm ii, Eu ii, and Dy ii, in the order of atomic number.
Who the band's 9th member is remains a mystery.
Who's number 9? Where's number 9?
Pentagon (PTG), a South Korean multinational boy band, released their ninth extended play Sum(me:r) on July 17, 2019, without Yan An due to health reasons, with lead single "Humph!" being co-produced by Giriboy and Hui.
Art Neuendorffer

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Ann
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Re: "Humph!"

Post by Ann » Tue Jan 14, 2020 7:10 pm

neufer wrote:
Tue Jan 14, 2020 4:52 pm
Ann wrote:
Tue Jan 14, 2020 4:17 pm
BDanielMayfield wrote:
Tue Jan 14, 2020 3:22 pm

Curious as to the identities of the 9 members of this heavy metal band:

Who the band's 9th member is remains a mystery.
Who's number 9? Where's number 9?
Pentagon (PTG), a South Korean multinational boy band, released their ninth extended play Sum(me:r) on July 17, 2019, without Yan An due to health reasons, with lead single "Humph!" being co-produced by Giriboy and Hui.
Art wrote:
Yan II Ann
Click to play embedded YouTube video.
Art, you are killing me (softly) with your words! :lol2:

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Re: NAOJ: Stellar Heavy Metals Can Trace History of Galaxies

Post by BDanielMayfield » Tue Jan 14, 2020 7:49 pm

Silliness aside, the eight elements identified as good makers in IR spectra of giants and supergiants are zinc(30), strontium(38), yttrium(39), zirconium(40), barium(56), samarium(62), europium(63) and dysprosium(66).

Comparing this set of elements with this:
https://upload.wikimedia.org/wikipedia/ ... le.svg.png
Shows us that
  • Zi forms in massive star SN 46% and WD SN 54%,
    Sr forms in massive star SN 13% and dying low mass stars 87%,
    Y forms in massive star SN 8% and dying low mass stars 92%,
    Zr forms in massive star SN 16% and dying low mass stars 84%,
    Ba forms in dying low mass stars 72% and NS mergers 28%,
    Sm forms in dying low mass stars 29% and NS mergers 71%,
    Eu forms in dying low mass stars 5% and NS mergers 95%,
    Dy forms in dying low mass stars 14% and NS mergers 86%.
"Happy are the peaceable ... "

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Re: NAOJ: Stellar Heavy Metals Can Trace History of Galaxies

Post by Ann » Wed Jan 15, 2020 6:34 am

BDanielMayfield wrote:
Tue Jan 14, 2020 7:49 pm
Silliness aside, the eight elements identified as good makers in IR spectra of giants and supergiants are zinc(30), strontium(38), yttrium(39), zirconium(40), barium(56), samarium(62), europium(63) and dysprosium(66).

Comparing this set of elements with this:
https://upload.wikimedia.org/wikipedia/ ... le.svg.png
Shows us that
  • Zi forms in massive star SN 46% and WD SN 54%,
    Sr forms in massive star SN 13% and dying low mass stars 87%,
    Y forms in massive star SN 8% and dying low mass stars 92%,
    Zr forms in massive star SN 16% and dying low mass stars 84%,
    Ba forms in dying low mass stars 72% and NS mergers 28%,
    Sm forms in dying low mass stars 29% and NS mergers 71%,
    Eu forms in dying low mass stars 5% and NS mergers 95%,
    Dy forms in dying low mass stars 14% and NS mergers 86%.
Thanks, Bruce! So we can see that these heavy elements were in most cases produced by dying low-mass stars.

Personally I'd like to say "intermediate-mass stars" instead of low-mass stars. I wouldn't call the Sun a low-mass star, seeing that it is in the top ten echelon of stellar mass in the galaxy and probably the Universe. Most stars, after all, are tiny little M dwarfs, and slightly more massive but still rather puny K-type main sequence stars are the second most common type of star in our galaxy.

My guess is that the Universe is young enough, and stars like the Sun last long enough, that most stars like the Sun have not yet lost their hold on life and turned into white dwarfs.

But, okay, a good number of them might be in the process of dying and pumping Y, Zr, Ba, Sm, Eu and Dy into the surrounding medium.

Ann
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