“Abodes of Advanced Life?” –Oldest Objects in the Universe Orbiting the Milky Way

Globular Cluster

 

Globular clusters,  of which seem to have formed together with the Milky Way, among the oldest objects in the universe, provide astronomers with natural laboratories for the study of stellar evolution processes and, perhaps, some speculate, may harbor advanced extraterrestrial life. An international group of astronomers using the Canada–France–Hawaii Telescope (CFHT) and Keck Observatory, has zoomed in on a satellite globular cluster, Laevens 3, one of 160 known to orbit the Milky Way in its galactic outer halo.

Globular clusters are among the oldest objects that formed about 11.5 billion years ago, 2.3 billion years after the Big Bang and shortly before the rate of cosmic star formation reached its peak, 10 billion years ago. “This period is known as cosmic high noon. The clusters are very bright and can be seen at very large distances, which means that they can give us clues as to how the galaxies were assembled during this period of maximum star formation,” says astrophysicist Rosa Amelia González-Lópezlira, researcher at the Institute of Radio Astronomy and Astrophysics of the National Autonomous University of Mexico who was not involved in the new study.

Possible Abodes of Advanced Civilizations

In January of 2016 we quoted Rosanne DiStefano of the Harvard-Smithsonian Center for Astrophysics (CfA) who said that “a globular cluster might be the first place in which intelligent life is identified in our galaxy.” Globular star clusters are extraordinary in almost every way. They’re densely packed, holding a million stars in a ball only about 100 light-years across on average, dating back almost to the birth of the Milky Way. And according to DiStefano’s research, they also could be extraordinarily good places to look for space-faring civilizations.

Globular Clusters Orbiting the Milky Way –“Might Be the First Place Intelligent Life is Identified” (CfA)

Located some 470,00 light-years away from the Earth, Laevens 3 (or Lae 3 for short) discovered in 2015 using the Pan-STARRS 1 telescope is a faint cluster, about eight billion years old, with a half-light radius of around 23 light-years and low metallicity. To put it’s distance in perspective, the Milky Way’s disk is only 100,000 light years across, or about an amazing sixth of the distance to the Andromeda Galaxy.

Observation of Laevens 3 Globular Cluster

Observations of such faint and distant satellite systems, reports Tomasz Nowakowski at Phys.org, could shed more light on the formation and evolution of our home galaxy, which inspired a new study by a team of astronomers led by Nicolas Longeard of the Observatory of Strasbourg in France.

“We present a photometric and spectroscopic study of the Milky Way satellite Laevens 3. Using MegaCam/CFHT g and i photometry and Keck II/DEIMOS multi-object spectroscopy, we refine the structural and stellar properties of the system,” the astronomers wrote in the paper.

“Globular Cluster Opportunity” –Harbors Milky Way’s Oldest Known Planet  

The study found that Laevens 3 is larger and older than previously thought. The color-magnitude diagram shows that it is about 13 billion years old.

According to the paper, all the results suggest that the cluster exhibits the main characteristics of Milky Way outer halo globular clusters. Moreover, the study found that Laevens 3 showcases signs of mass segregation, which confirms the globular cluster nature of this system.

“Overall, Laevens 3 shares the typical properties of the Milky Way’s outer halo globular clusters. Furthermore, we find that this system shows signs of mass segregation, which strengthens our conclusion that Laevens 3 is a globular cluster,” the researchers concluded with an outer halo orbit with a pericenter of about 133,000 light-years and an apocenter of approximately 279,000 light-years.
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The Daily Galaxy via Phys.org  and New Scientist

The Hubble image at the top of the page, Messier 54, could be just another globular cluster, but this dense and faint group of stars was in fact the first globular cluster found that is outside our galaxy.

 

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