10775

The “chandelier” star cluster captured by Hubble: a globular cluster NGC 6723 in the direction of Sagittarius, about 27,000 light-years away—it's not a one-and-done star-formation event.

According to an ESA/Hubble and NASA joint press release on 2026-06-26: NGC 6723 is sometimes also called the Chandelier Cluster, made up of tens of thousands to over a million gravitationally bound stars. It lies about 27,000 light-years away in Sagittarius. The Milky Way is known to contain more than 150 globular clusters; these objects often exceed 10 billion years in age, and are among the earliest structures to form in the Milky Way.

A key point of emphasis: For a long time, it was thought that all the stars in a globular cluster formed at the same time and had the same chemical composition. Two rounds of Hubble observations changed this simple story. First, observation program #10775 (PI: Sarajedini) used visible and near-infrared imaging to survey 65 globular clusters in the Milky Way. Later, program #13297 (PI: Piotto), leveraging ultraviolet sensitivity, detected subtle differences in chemical composition and estimated an age spread. For NGC 6723, the evidence indicates that there were two episodes of star formation occurring very close together—the second episode happened within about 634 million years after the first. For a cluster older than 10 billion years, that gap is essentially a “blink.”

Independent verification: A Live Science report dated 2026-08-30 on the same topic confirmed the approximately 27,000 light-year distance, the Sagittarius location, the ~634 million-year separation between the two star-formation episodes, and that the cluster is not a single, simple stellar population—consistent with the ESA/NASA press release.

Image source: ESA/Hubble & NASA, A. Sarajedini, G. Piotto
Data as of: ESA/Hubble / NASA press release 2026-06-26
#Hubble #astronomy