Hubble Captures Asymmetric Spiral Galaxy NGC 4654

• NGC 4654 is an intermediate spiral galaxy 72 million light-years away in the Virgo Cluster, characterized by a distinct asymmetric shape and a gas tail.
• Its lopsided appearance is caused by a combination of ram pressure stripping and a past gravitational interaction with a neighboring galaxy.
• Despite losing gas, the galaxy maintains a robust star formation rate of nearly two solar masses per year.

Causes of Asymmetry

• Ram Pressure Stripping: As the galaxy moves at high velocity through the hot, dense intracluster medium of the Virgo Cluster, pressure compresses the leading edge and strips gas away to form an elongated tail.
• Gravitational Interaction: Approximately 500 million years ago, a fly-by with NGC 4639 likely stripped gas from one side, significantly contributing to the unusual distribution of stars compared to typical spiral galaxies.

Star Formation Activity

• Huble observations highlight regions of active star birth, visible as bright pink bubbles of ionized gas.
• The star formation rate is notable because many galaxies undergoing ram pressure stripping typically suffer from reduced star production due to the loss of the cold gas required for collapse.
• Current data supports research programs aimed at understanding the relationship between galactic gas movement and star cluster development.