Astronomers find ‘gold standard’ superstar in Milky Way

Neutron stars are the collapsed cores of supergiant stars, and so are the smallest and densest known celestial objects

In our sun’s neighborhood from the Milky Way Galaxy is really a relatively bright star, and it, astronomers have been able to identify the widest range of elements in a star further than our solar system yet.

The study, led by University of Michigan  astronomer   Ian Roederer, has identified 65 elements in the star, HD 222925. Forty-two of the elements identified are  heavy elements   that are listed across the bottom of the periodic table of elements.

Identifying these elements in one star will help astronomers understand what’s called the “ fast neutron capture process, ” or one of the major ways by which heavy elements within the universe were created. Their own results are posted on arXiv and have been accepted with regard to publication in  The Astrophysical Journal Supplement   series.

“ To the best of the knowledge, that’s a record for just about any object beyond our solar power system. And what makes this superstar so unique is that it has a very high relative proportion from the elements listed along the bottom part two-thirds of the periodic table. We even detected gold, ” Roederer said. “ These elements were created by the rapid neutron catch process. That’s really the issue we’re trying to study: the physics in understanding how, where and when those elements had been made. ”

The process, also called the “ r-process, ” begins with all the presence of lighter elements such as iron. Then, rapidly— on the order of a second— neutrons are added to the particular nuclei of the lighter components. This creates  weightier elements   like selenium, silver, tellurium, platinum, gold and thorium, the type found in HD 222925, and all sorts of which are rarely detected in stars, according to the astronomers.

“ You need plenty of neutrons that are free and also a very high energy set of problems to liberate them and add them to the nuclei of atoms, ” Roederer said. “ There not necessarily very many environments in which that may happen— two, maybe. ”

One of these environments has been confirmed: the joining of  neutron celebrities . Neutron stars are the collapsed cores of supergiant stars, and are the smallest and densest known celestial objects. The collision of neutron star pairs causes gravitational waves and in 2017, astronomers first detected  gravitational waves   from merging neutron stars. Yet another way the r-process might occur is after the explosive dying of massive stars.

“ That’s a significant step forward: recognizing where the r-process can occur. But it’s a a lot bigger step to say, ‘ What did that event actually do? What was produced there? ‘” Roederer said. “ That’s where our research comes in. ”

The elements Roederer and his group identified in HD 222925 were produced in either a huge supernovae or a merger of  neutron   stars very early within the universe. The material has been ejected and thrown back in space, where it later reformed into the star Roederer is studying today.

This star can then be used as a proxy just for what one of those events would have produced. Any model developed in the future that demonstrates the way the r-process or nature generates elements on the bottom two-thirds of the periodic table should have the same signature as HIGH DEFINITION 222925, Roederer says.

Crucially, the astronomers used an instrument on the Hubble Space Telescope that can collect  uaviolet spectra . This instrument was type in allowing the astronomers to gather light in the uaviolet portion of the light spectrum— light which is faint, coming from a cool celebrity such as HD 222925.

The astronomers furthermore used one of the Magellan telescopes— a consortium of which U-M is a partner— at Todas las Campanas Observatory in Chile to collect light from HIGH-DEFINITION 222925 in the optical area of the light spectrum.

These spectra encode the “ chemical fingerprint” associated with elements within stars, plus reading these spectra enables the astronomers not only to distinguish the elements contained in the star, but also how much of an element the particular star contains.

Anna Frebel is a co-author of the study and teacher of physics at the Massachusetts Institute of Technology. She helped with the overall interpretation of the HD 222925’s element having plenty pattern and how it informs our understanding of the origin of the elements in the cosmos.

“ We now understand the detailed element-by-element output of some r-process event that happened early in the universe, ” Frebel said. “ Any model that attempts to understand what’s going on with the r-process has to be able to reproduce that. ”

Most of the study co-authors are section of a group called the R-Process Connections, a group of astrophysicists dedicated to resolving the big questions of the r-process. This project marks one of the team’s key goals: identifying which elements, and in what amounts, were produced in the  r-process   in an unprecedented level of details.

Leave a Reply

Your email address will not be published. Required fields are marked *