From the January 2024 issue

Tadpole Galaxy

By | Published: January 1, 2024 | Last updated on January 8, 2024

Dim, distant, and distorted, the Tadpole Galaxy (UGC 10214) in the constellation Draco the Dragon is a nearly edge-on barred spiral galaxy sporting a massive tail of stars that stretches across 280,000 light-years of space. Apparently, 100 million years ago a small compact spiral galaxy crossed in front of UGC 10214 (as seen from our perspective on Earth some 420 million light-years distant), and their mutual gravitational pulls resulted in an extragalactic collision.

When a large galaxy smashes into a smaller one, the smaller galaxy’s stars are either incorporated into the larger galaxy or ejected into intergalactic space. When UGC 10214 took hold of the mini-spiral, it swung the smaller galaxy some 300,000 light-years behind its “back.” In the process, tidal forces ripped away the smaller galaxy’s stars, gas, and dust, stringing them out in a long tadpolelike tail — instigating prodigious star formation along the tidal tail and in UGC 10214’s arms. As it ages, the Tadpole Galaxy will likely lose its tail. Meanwhile, some of the clusters within the tail will become orbiting satellites of UGC 10214, while others will perhaps be consumed by the barred spiral.

You’ll find UGC 10214 about 3° south of Theta (θ) Draconis. It shines dimly at magnitude 14.6, so 12-inch or larger telescopes and powers between 150x and 200x will serve observers best, as will extremely dark skies and excellent transparency.