Profile

Cover photo
Nuclear Astrophysics
2,378 followers|530,046 views
AboutPosts

Stream

Nuclear Astrophysics

Shared publicly  - 
 
Happy Birthday, Willy!

One of the founding fathers of the field of Nuclear Astrophysics, he was born August 9th, 1911, in Pittsburgh, Pennsylvania. He received the Nobel Prize for Physics in 1983 for his theoretical and experimental studies of the nuclear reactions of importance in the formation of the chemical elements in the universe.
2
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
Join the NSF hangout this Thursday to learn more about the Joint Institute for Nuclear Astrophysics, an NSF-funded Physics Frontiers Center (PFC).
 
Thursday, July 30, 2:00 pm ET: NSF-funded Physics Frontiers Centers (PFCs) are pushing the frontiers of science across the disciplines of physics. The Joint Institute for Nuclear Astrophysics Center for Evolution of the Elements (JINA-CEE) studies unknown aspects of nuclear processes that naturally occur in the universe to explain the origin of the elements and to reveal the properties of dense matter in cosmic environments. At 2 pm ET / 1 pm CT on Thursday, July 30, the NSF Physics Division will host a live hour-long Google Hangout with JINA-CEE. We’ll talk with the JINA-CEE Director and other members about the exciting science going on there and its innovative activities. You’ll even be able to participate in the discussion by submitting a question on Twitter using #NSFLive. If you are interested in cutting edge science, tune in to hear all about JINA-CEE and just what makes it a PFC.

Participants:

• HENDRIK SCHATZ – Michigan State University, Director of the Joint Institute for Nuclear Astrophysics Center for Evolution of the Elements (JINA-CEE), Nuclear Physicist. Research: Accelerator based nuclear physics experiments of stellar processes. 

• FRANK TIMMES – Arizona State University, Co-Investigator of JINA-CEE, Astrophysicist.  Research: Computer Models of Stars and Stellar Explosions. 

• TIMOTHY BEERS – University of Notre Dame, Co-Investigator of JINA-CEE. Astronomer. Research: Observations of elements in the spectra of ancient stars.

• CARL FIELDS – Arizona State University, Undergraduate student at JINA-CEE. Research: compact objects, supernovae, and stellar physics with emphasis on evolution and nucleosynthesis. 

• MICHA KILBURN -  University of Notre Dame, JINA-CEE Director of Education and Outreach

• GREG MACK (moderator) – AAAS Science & Technology Policy Fellow in the National Science Foundation Physics Division.
This Hangout On Air is hosted by National Science Foundation. The live video broadcast will begin soon.
Q&A
Preview
Live

5 comments on original post
1
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
Happy 100th Birthday, Sir Fred Hoyle

Today we celebrate the centenary of the birthday of one of the fathers of the field of nuclear astrophysics.

Being a remarkable and very inventive scientist, Sir Fred Hoyle and his science collaborators published a ground-breaking work in 1957, laying the foundation for research on the origin of the elements in stars and stellar explosions. Most of their ideas are still regarded as correct, although some change had to be made to certain details, accommodating new results and observations.

But Fred Hoyle not only worked on nuclear astrophysics, he was a person with many interests. He also coined the term "Big Bang", intended as a derogative expression for a concept he did not like.
(In fact, the 1957 paper was devised to refute the idea that all chemical elements were made in the Big Bang, as Oppenheimer and other scientists at that time thought. Later, this turned out to be correct, only the lightest elements H, He, Li, and Be stem from primordial times of the Cosmos. It did not do away with the Big Bang, though, as Fred Hoyle hoped.)

His many ideas and his often undiplomatic behaviour sparked many controversies, both scientifically and unscientifically.

Happy 100th Birthday to a remarkably productive scientist!
7
4
Joe Philip Ninan's profile photoTed Welles's profile photo
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
Good news for the Joint Institute for Nuclear Astrophysics!

The funding for this NSF Physics Frontier Center has been renewed for the third time. A remarkable achievement in these days of reduced funding and increased competition, not only rewarding the hard work of many highly motivated individuals but also underlining the importance and relevance of this research field.

Congratulations!!

http://www.jinaweb.org/
1
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
Supernova remnant
 
Supernova Remnant: A long observation with Chandra of the supernova remnant MSH 11-62 reveals an irregular shell of hot gas, shown in red, surrounding an extended nebula of high energy X-rays, shown in blue. Even though scientists have yet to detect any pulsations from the central object within MSH 11-62, the structure around it has many of the same characteristics as other pulsar wind nebulas. The reverse shock and other, secondary shocks within MSH 11-62 appear to have begun to crush the pulsar wind nebula, possibly contributing to its elongated shape. (Note: the orientation of this image has been rotated by 24 degrees so that north is pointed to the upper left.)

Image credit: NASA/CXC/SAO/P. Slane et al.

#nasa #chandra #xray#astronomy #space #nebula #science #supernova

4
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
Touchdown!

The comet lander Philae successfully attached itself to the surface of the comet.

A historical day: The first comet landing.

Congratulations!
3
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
 
There is a star with a calculated age that is older than the universe. That might seem like a contradiction, but it's not.
The star HD 140283 is a subgiant star with an estimated age of 14.46 billion years. That might raise an eyebrow or two for those of you who remember that the age of the universe is estimated as 13.77 billion years. It would seem that this particular star, sometimes referred to as the Methuselah star is older than the universe.
2
3
Vin “Aravinda” P's profile photoDebbie Allport's profile photo
Add a comment...
Have them in circles
2,378 people
Olaf Prause's profile photo
Raymond D. Crookes's profile photo
Atish Basant's profile photo
Graveyard Shift Astronomy's profile photo
Eric Rineer's profile photo
ranjith chandra's profile photo
Martijn Roelandse's profile photo
James Nussbaum's profile photo
Kathy Yoho's profile photo

Nuclear Astrophysics

Shared publicly  - 
 
 
Solving the Lithium Enigma

Why do young stars contain so much lithium? That might seem an odd question, but it’s a question that has nagged astronomers for quite some time.

The story of lithium in the universe begins with the big bang. In the early moments of the big bang, the first elements were created through a process known as baryogenesis nucleosynthesis. Most of the matter created through baryogenesis nucleosynthesis was hydrogen and helium (numbers 1 and 2 on the periodic table), but the big bang also produced a bit of lithium (the number 3 element). According to our model of the big bang, for every 10 billion hydrogen atoms produced, only one lithium atom would form. This might seem like an extraordinarily small amount, but it’s actually more lithium than we actually observe in the universe. It would seem our prediction didn’t quite match reality.

But we also know that lithium can be consumed in the heart of a star. Stars produce light and heat through a complex process of nuclear reactions. As a result, lighter elements such as hydrogen can be fused into heavier elements like carbon, oxygen and iron. But some elements are easier to fuse than others, and it turns out that lithium readily fuses into other elements, a process known as lithium burning. As a result, stars can reduce the amount of lithium in the universe. Perhaps that would explain why there is less lithium than our initial model predicted. It’s a good idea, but there’s just one problem. If lithium burning were the solution, then we would expect older stars to have more lithium and younger stars less, since over time there would be less lithium available. What we actually observe is that older stars actually have less lithium than younger stars. What started with one mystery then became two.

But back in the 1970s it was proposed that the higher levels of lithium in younger stars might be due to nova explosions of older stars. Unlike a supernova, where a star is completely destroyed (with the exception of a remnant neutron star or black hole) a nova is due to a runaway nuclear reaction on the surface of a white dwarf. This nuclear reaction could produce lithium, and thus create the abundance of lithium in younger stars. New observations have actually confirmed this effect.

The results come from a nova known as V1369 Cen, which was a bright nova that appeared in the constellation Centaurus in 2013. Because of its brightness, the team was able to observe its spectrum in detail, and they found clear evidence of lithium in the nova. This lithium was cast out into interstellar space, making it available for later stars that happen to form. The measured amount of lithium was small, but combined with the estimated billions of novae that have occurred throughout the history of our galaxy, it is enough to account for the observed rise in lithium levels.

So it seems that the lithium enigma isn’t such an enigma after all.

Paper: Luca Izzo et al. Early optical spectra of nova V1369 Cen show presence of Lithium. ApJ 808 L14 (2015)
Why do young stars contain so much lithium? That might seem an odd question, but it's a question that has nagged astronomers for quite some time.
18 comments on original post
1
Thom Green's profile photo
 
maybe they were over prescribed
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
Happy 4th of July to those in the U.S.A.

From the nucleosynthesis point of view, such stellar explosions are not only impressive because of their energy and complexity but they also synthesize elements and isotopes from the stars initial make-up and/or distribute them in the Galaxy. New stars and planetary systems are then formed from the "ashes" of such events.
 
Interstellar Explosions for the Fourth of July
As you enjoy fireworks this Fourth of July, what you won’t see are countless eruptions of light, plasma, gamma rays and superheated gasses dancing above your heads. These galactic explosions occur nonstop throughout the cosmos.

Click the link to see more of the biggest and brightest lightshows in the universe. http://go.nasa.gov/1NzdCty
4 comments on original post
3
Sarah English's profile photo
 
Thank you.
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
 
Happy Birthday, Alistair W. G. Cameron

Born on June 21, 1925 in Canada, he was one of the founding fathers of the field of Nuclear Astrophysics.

Completely independently of other researchers, he developed pioneering ideas and models for understanding the origin of the cosmic elements from which most of our current ideas concerning element formation followed. Most of these ideas were summarized in 1957 scientific article which appeared in parallel to, but completely independently from, a similar article by Burbidge, Burbidge, Fowler and Hoyle, a more widely known research group at that time.

Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. Also particularly noteworthy is his explanation of the formation of the Moon caused by a gigantic collision between a sub-planet and the young Earth. This is the currently accepted model for the origin of the Moon.

He was a remarkable person in many respects, as can be seen from his life told in these publications:
http://news.harvard.edu/gazette/story/2009/12/alastair-graham-walter-cameron/
http://www.nature.com/nature/journal/v438/n7069/full/438752a.html
And as also told by himself:
http://www.aip.org/history/ohilist/33763.html

(picture credit: http://pos.sissa.it/archive/conferences/028/205/NIC-IX_205.pdf )
#nucleosynthesis #moon 
2
1
Thomas Rauscher's profile photo
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
Studying the aftermath of a supernova explosion
 
Astronomers dissect the aftermath of a Supernova.

A team of astronomers has used radio telescopes in Australia and Chile to see inside the remains of a supernova. The supernova, known as SN1987A, was first seen by observers in the Southern Hemisphere in 1987 when a giant star suddenly exploded at the edge of a nearby dwarf galaxy called the Large Magellanic Cloud. Learn more: http://buff.ly/1AYnGd7
6
1
Debbie Allport's profile photo
Add a comment...

Nuclear Astrophysics

Shared publicly  - 
 
The Cat's Eye Nebula - remains of a star

Seen with the Hubble Space Telescope, these expanding shells of gas are three thousand light-years away from Earth and about half a light year across. In the center of this nebula is a dying star, a sun-like star that has shrugged off its outer layers in several pulses, as seen by the concentric shells of gas moving outwards. The innermost structures seem to indicate more violent activity which currently is not well understood yet but may be due to a core He-flash, a violent phase of nuclear burning. In the end, a hot White Dwarf will be formed in the center that will just cool down while the ejected gas clouds keep expanding and cooling as well. The typical final fate of a low-mass star and our Sun will meet the same fate in 4.5 billion years.

Image Credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA)
A different astronomy and space science related image is featured each day, along with a brief explanation.
2
1
Debbie Allport's profile photo
Add a comment...
People
Have them in circles
2,378 people
Olaf Prause's profile photo
Raymond D. Crookes's profile photo
Atish Basant's profile photo
Graveyard Shift Astronomy's profile photo
Eric Rineer's profile photo
ranjith chandra's profile photo
Martijn Roelandse's profile photo
James Nussbaum's profile photo
Kathy Yoho's profile photo
Links
Story
Tagline
scientific research in astrophysics and basic nuclear science
Introduction
Research news and other info mainly related to nucleosynthesis and nuclear astrophysics.