Webb Sees Globular Clusters Forming in the Early Universe

The Cosmic Gems arc as observed by the JWST. The clusters have the attributes of gravitationally-bound proto-Globular Clusters. Credit: ESA/Webb, NASA & CSA, L. Bradley (STScI), A. Adamo (Stockholm University) and the Cosmic Spring collaboration.

Picture the Universe’s ancient beginnings. In the vast darkness, light was emitted from a particular galaxy only 460 million years after the Big Bang. On the way, the light was shifted into the infrared and magnified by a massive gravitational lens before finally reaching the James Webb Space Telescope.

The galaxy is called the Cosmic Gems arc, and it held some surprises for astronomers.

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The Nearby Star Clusters Come from Only Three Places

The most well-known open cluster is probably the Pleiades, or Seven Sisters. The Japanese call it the Subaru cluster, and keen observers might recognize its pattern on the Subaru automobile logo. New research shows that the Pleiades and more than 150 other star clusters all originated in only three star-forming regions. Image: By NASA, ESA, AURA/Caltech, Palomar Observatory. http://hubblesite.org/newscenter/archive/releases/2004/20/image/a/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7805481

Many astronomy-interested people know of the Hyades and the Pleiades. They’re star clusters in the Taurus constellation. They’re two out of a handful of star clusters that are visible to the unaided eye under dark sky conditions.

It turns out that these clusters, along with more than 150 other nearby clusters, all originated in only three massive star-forming regions.

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JWST Sees a Milky Way-Like Galaxy Coming Together in the Early Universe

The ancient Firefly Sparkle galaxy is precursor to galaxies like the Milky Way. The JWST found ten separate clusters in the galaxy that show how the galaxy is growing through mergers. Image Credit: Mowla et al. 2024.

The gigantic galaxies we see in the Universe today, including our own Milky Way galaxy, started out far smaller. Mergers throughout the Universe’s 13.7 billion years gradually assembled today’s massive galaxies. But they may have begun as mere star clusters.

In an effort to understand the earliest galaxies, the JWST has examined their ancient light for clues as to how they became so massive.

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Astronomers Have a New Trick to Work out the Age of Stars

A frame from the Kepler Telescope showing a couple binary systems. Credit: AIP/ David Gruner, NASA (Kepler FFI) & ESO (zoomed)

Twinkle, twinkle little star, I wonder just how old you are.

It isn’t an easy question to answer. Stars are notoriously difficult to age. We know the age of the Sun because we happen to live on one of its orbiting rocks, and we know very well how old the rock is. Without that information, things become a bit more fuzzy. But that could change thanks to a new study.

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How Old is That Star? Ask a Computer

An open cluster of stars known as IC 4651, a stellar grouping that lies at in the constellation of Ara (The Altar). Credit: ESO

When measuring distances in the Universe, astronomers rely on what is known as the “Distance Ladder” – a succession of methods by which distances are measured to objects that are increasingly far from us. But what about age? Knowing with precision how old stars, star clusters, and galaxies are is also paramount to determining how the cosmos has evolved. Thanks to a new machine learning technique developed by researchers from Keele University, astronomers may have established the first rung on a “cosmic age ladder.”

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JWST Sees Merging Galaxies Releasing the Light of a Trillion Suns

ARP 220 is a pair of merging galaxies about 250 million light years away. Image Credit: NASA, ESA, CSA, STScI, Alyssa Pagan (STScI)

If we want to know what it’ll look like in about 4.5 billion years when our galaxy merges with Andromeda, we might take a look at ARP 220. ARP 220 is a pair of galaxies that are in the process of merging. The merging galaxies emit brilliant infrared light, and the James Webb Space Telescope captured that light in a vivid portrait.

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The Brightest Star in the Sky, Sirius, was Hiding a Cluster of Stars. Found by Gaia

Obscured Sirius reveals Gaia 1 cluster. Credit and Copyright: H. Kaiser/ESA

In December of 2013, the European Space Agency’s Gaia mission took to space. Since that time, this space observatory has been studying a billion astronomical objects – including stars, planets, comets, asteroids and galaxies – for the sake of creating the most precise 3D space catalog ever made. By the time the mission wraps up (later this year, barring extensions), it is expected to reveal some truly amazing things about our Universe.

In fact, with the first release of its data, the Gaia probe revealed something that has gone completely unnoticed until now. While viewing Sirius, the brightest star in the night sky, Gaia revealed a stellar cluster that had previously been obscured by Sirius’ bright light. This cluster – now known as the Gaia 1 Cluster – is now available to the public thanks to a picture that was taken by an amateur astronomer from Germany.

Given its brightness and the fact that it is visible from just about anywhere on the planet, Sirius has been known since antiquity, and was featured prominently in the astrological and astronomical traditions of many cultures. To the ancient Egyptians, the star was used to keep track of time and agriculture, since its return to the sky was linked to the annual flooding of the Nile.

Artist’s impression of a white dwarf star in orbit around Sirius (a main sequence white dwarf). Credit: NASA, ESA and G. Bacon (STScI)

In Ancient Greek mythology, Sirius represented the eye of the Canis Major constellation. Along with Canis Minor, it formed the Great Dog that diligently followed Orion, the Hunter. In Chinese astronomy, the star is known as the star of the “celestial wolf” and lies in the Mansion of Jing. And when Ptolemy created his influential astronomical tract in the 3rd century CE (the Almagest), he used Sirius as the location for the globe’s central meridian.

By the mid-19th century, astronomers determined that Sirius is actually a binary star system. Essentially, the star system consists of a main sequence white dwarf that is roughly two Solar masses and a white dwarf that is slightly more massive than our Sun. Sirius’ bright appearance means that astronomers have had plenty of light to study the star’s properties, but also causes it to outshine other celestial objects in its vicinity.

However, in the course of counting the stars around Sirius, Gaia’s sophisticated instruments managed to detect the Gaia 1 Cluster for the first time. News of both this cluster and another newly-discovered one (the Gaia 2 Cluster) became public after the first release of Gaia data, which took place in September 2016. News of this discovery sent ripples through the astronomical community and has led to much research into this cluster and its companion.

News of the discovery also prompted attempts to visually capture the cluster. Roughly a year ago, Harald Kaiser – an amateur astronomer from Karlsruhe, Germany – attended a public talk about the Gaia mission, where he learned about the Gaia 1 Cluster being spotted near Sirius. Kaiser then eagerly waited for the next clear night so he could find the cluster himself using his 30 cm telescope.

The ESA’s Gaia mission is currently on a five-year mission to map the stars of the Milky Way. Credit: ESA/ATG medialab; background: ESO/S. Brunier.

After snapping a picture of Sirius and correcting for its bright glare, he was able to capture some of the brightest stars in the cluster. As you can see from the image he took (at top), the cluster lies slightly to the left of Sirius and shows a smattering of some of its largest and brightest stars. In addition to revealing the location of this cluster, Kaiser’s efforts are also part of a larger effort to capitalize on the Gaia mission’s progress.

According to a study released in February of last year – led by Sergey Kopsov of Carnegie Melon University – Gaia 1 is a particularly massive cluster. In essence, it weighs in at an impressive 22,000 Solar Masses, is about 29 light-years (9 parsecs) in diameter, and is located 15,000 light years (4.6 kiloparsecs) from Earth. In addition to its size and the fact that it was previously undiscovered, it’s proximity also makes it an opportune target for future research.

The announcement of this cluster has also caused a fair degree of excitement in the scientific community since it validates the capabilities of Gaia and serves as an example of the kinds of things it is expected to reveal. Astronomers are now looking forward to Gaia’s second data release (planned for April 25th) which is expected to provide even more possibilities for new and exciting discoveries.

And be sure to check out this video about the Gaia mission, courtesy of the ESA:

Further Reading: ESA

Hubble Telescope Celebrates 25 Years in Space With Spectacular New Image

This NASA/ESA Hubble Space Telescope image of the cluster Westerlund 2 and its surroundings has been released to celebrate Hubble’s 25th year in orbit and a quarter of a century of new discoveries, stunning images and outstanding science. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI), and the Westerlund 2 Science Team.

Images from space don’t get any prettier than this. A new image from the Hubble Space Telescope was released today to commemorate a quarter century of exploring the Solar System and beyond since the launch of the telescope on April 24, 1990. It shows a giant cluster of about 3,000 stars called Westerlund 2, located 20,000 light-years away from Earth in the constellation Carina. NASA describes the new image as a “brilliant tapestry of young stars flaring to life resemble a glittering fireworks display.”

The Hubble Teams are giving away a few “gifts” to everyone to celebrate this silver anniversary — see below!

“Hubble has completely transformed our view of the universe, revealing the true beauty and richness of the cosmos” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate. “This vista of starry fireworks and glowing gas is a fitting image for our celebration of 25 years of amazing Hubble science.”

The cluster is named after Swedish astronomer Bengt Westerlund who discovered the grouping in the 1960s.

You can get access to larger versions of the image here at ESA’s Hubble website, or at NASA’s HubbleSite.

There are anniversary events occurring around the US and the world. Here is a listing of at the Hubble anniversary site, where people can also find science articles, educational resources, downloadable presentations, and more:

And here’s a downloadable 25th anniversary gift for everyone: Hubble is offering a free ebook of 25 of Hubble’s most significant images, which can be found at this link or at iTunes.

See a stunning gallery of all the ‘anniversary’ images that have been released by the Hubble teams over the last 25 years at this Flickr gallery.

And finally, here’s an excellent visualization of a flight to the star cluster Westerlund 2:

Too WISE to be Fooled by Dust: Over 300 New Star Clusters Discovered

A new study by Brazilian astronomers details the discoveries of some 300 new star clusters using the WISE space telescope (credit NASA/JPL-Caltech/UCLA).

Brazilian astronomers have discovered some 300+ star clusters that were largely overlooked owing to sizable obscuration by dust.  The astronomers, from the Universidade Federal do Rio Grande do Sul, used data obtained by NASA’s WISE (Wide-Field Infrared Survey Explorer) space telescope to detect the clusters.

“WISE is a powerful tool to probe … young clusters throughout the Galaxy”, remarked the group.  The clusters discovered were previously overlooked because the constituent stars are deeply embedded in their parent molecular cloud, and are encompassed by dust.   Stars and star clusters can emerge from such environments.

The group added that, “The present catalog of new clusters will certainly become a major source for future studies of star cluster formation.”   Indeed, WISE is well-suited to identify new stars and their host clusters because infrared radiation is less sensitive to dust obscuration.  The infrared part of the electromagnetic spectrum is sampled by WISE.

An optical (DSS) and infrared (WISE) image of the same field.  A cluster of young stars is not apparent in the optical (left) image owing to obscuration by dust.  However, a young star cluster is apparent in the right image because the dust reradiates the absorbed radiation in the infrared regime.  The new study highlights the discovery of numerous  star clusters discovered using infrared (WISE) data (image credit: DSS/NASA and assembly by D. Majaess).
An optical (DSS) and infrared (WISE) image of the same field. A cluster of young stars is not apparent in the optical (left) image owing to obscuration by dust.  However, a young star cluster is readily apparent in the right image because dust obscuration is significantly less at infrared wavelengths. A new study by a team of astronomers highlights the discovery of numerous star clusters using WISE data (image credit: DSS/NASA/IPAC and assembly by D. Majaess).

Historically, new star clusters were often identified while inspecting photographic plates imaged at (or near) visible wavelengths (i.e., the same wavelengths sampled by the eye).  Young embedded clusters were consequently under-sampled since the amount of obscuration by dust is wavelength dependent.  As indicated in the figure above, the infrared observations penetrate the dust by comparison to optical observations.

The latest generation of infrared survey telescopes (e.g., Spitzer and WISE) are thus excellent instruments for detecting clusters embedded in their parent cloud, or hidden from detection because of dust lying along the sight-line.  The team notes that, “The Galaxy appears to contain 100000 open clusters, but only some 2000 have established astrophysical parameters.”  It is hoped that continued investigations using WISE and Spitzer will help astronomers minimize that gap.

The discoveries are described in a new study by D. Camargo, E. Bica, and C. Bonatto that is entitled “New Glactic embedded cluster and candidates from a WISE survey“.   The study has been accepted for publication, and will appear in a forthcoming issue of the journal New Astronomy.  For more information on Galactic star clusters see the Dias et al. catalog, the WEBDA catalog, or the Star Clusters Young & Old Newsletter.  Thanks to K. MacLeod for the title suggestion.

The WISE (Wide-field Infrared Survey Explorer) space telescope was used to discover numerous new star clusters (image credit: NASA)(.
The WISE (Wide-field Infrared Survey Explorer) space telescope was used to discover numerous star clusters (image credit: NASA).