Tadpole Galaxy

The Tadpole Galaxy is a disrupted barred spiral galaxy located 420 million light-years from Earth in the northern constellation Draco. Its most dramatic feature is a massive trail of stars about 280,000 light-years long; the size of the galaxy has been attributed to a merger with a smaller galaxy that is believed to have occurred about 100 million years ago.[2] The galaxy is filled with bright blue star clusters.

Tadpole Galaxy
The Tadpole Galaxy recorded with the Hubble Space Telescope's Advanced Camera for Surveys
Observation data (J2000 epoch)
Constellation	Draco
Right ascension	16h 06m 03.9s[1]
Declination	+55° 25′ 32″[1]
Redshift	9401 ± 15 km/s[1]
Distance	400 Mly
Apparent magnitude (V)	14.4[1]
Characteristics
Type	SB(s)c pec[1]
Apparent size (V)	3′.6 × 0′.8[1]
Notable features	Collided galaxy
Other designations
UGC 10214,[1] Arp 188,[1] PGC 57129[1]

It is hypothesized that a more compact intruder galaxy crossed in front of the Tadpole Galaxy—from left to right from the perspective of Earth—and was slung around behind the Tadpole by their mutual gravitational attraction. During this close encounter, tidal forces drew out the spiral galaxy's stars, gas, and dust, forming the conspicuous tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper left. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older; the tail's star clusters forming smaller satellites of the large spiral galaxy.