From the March 2025 issue

M17 stars in a cosmic vista

By | Published: March 18, 2025

You could forgive M17 for having an identity crisis. Observers refer to this emission region as the Omega, the Swan, and even the Checkmark Nebula. M17 doesn’t even know what constellation to call home — most of it lies in Sagittarius, but its northern edge crosses into Serpens. Yet no one can deny the stellar nursery’s good looks. This infrared view penetrates much of the dust that obscures the budding star cluster emerging within M17. Astronomers captured the Swan, which resides 5,500 light-years from Earth, with the 4.1-meter Visible and Infrared Telescope for Astronomy (VISTA) located on Cerro Paranal in Chile. The image is just a tiny piece of a giant infrared map covering an area equal to 8,600 Full Moons. The survey took 13 years to complete and captured more than 1.5 billion objects.