Key Takeaways

  1. NASA’s Hubble Space Telescope captures a captivating cosmic caterpillar, a light-year-long knot of interstellar gas and dust.
  2. Harsh winds from 65 of the hottest, brightest stars, known as O-type stars, sculpt and shape the celestial caterpillar with powerful ultraviolet radiation.
  3. The Cygnus OB2 association, with its massive collective mass, plays a central role in influencing the caterpillar’s evolution.
  4. IRAS 20324+4057, the protostar at the caterpillar’s core, struggles to collect material as radiation erodes its gas envelope, impacting its final size.
  5. Spectroscopic observations reveal the central star’s active process of accumulating material, leaving its ultimate fate uncertain – a “heavy-weight” or “light-weight” star.

NASA’s Hubble Space Telescope has unveiled a fascinating sight in the depths of space: a cosmic caterpillar, stretching across a distance of one light-year. This intriguing knot of interstellar gas and dust appears as if it’s on its way to a celestial feast. However, the real story lies in the powerful forces shaping its existence. Harsh winds from an assembly of 65 scorching, O-type stars, situated 15 light-years away from the caterpillar, are relentlessly bombarding it with ultraviolet radiation, sculpting its elongated form.

The culprit stars belong to the Cygnus OB2 association, comprising not just the 65 intensely luminous O-type stars but also 500 slightly less bright yet still highly radiant B-type stars. Together, this association possesses an astounding mass over 30,000 times that of our Sun. At the heart of the cosmic caterpillar lies IRAS 20324+4057, a protostar in its nascent stage, actively gathering material from the surrounding gas envelope. Yet, the relentless radiation from Cygnus OB2 threatens the protostar’s growth. If the envelope is eroded before it can amass sufficient mass, the protostar’s final size may be considerably reduced.

Spectroscopic examinations of the central star within IRAS 20324+4057 reveal that it is still in the process of heavily accumulating material from its outer envelope, a vital step in its evolution. The outcome remains uncertain – whether it will mature into a “heavy-weight” star or remain a “light-weight” in terms of mass. This stunning composite image, combining Hubble data and ground-based hydrogen data, provides a mesmerizing glimpse into this distant spectacle, which lies an astonishing 4,500 light-years away in the Cygnus constellation.


Image credit: Stefano Zamblera | Xiulong



Composite HST ACS/WFC (false-color) image (size 62.7′′ × 27.1′′) of I 20324 taken through two broad-band filters F606W (green) and F814W (red). Credit: arXiv


Four of the 5 NIRSpec FS apertures are shown over-plotted on an HST ACS/WFC F814 image of the protostar IRAS 20324+4057. The target is within the S200A1 slit, shown at the upper right. Credit: JWST/NASA

0 0 votes
Article Rating
Notify of

Inline Feedbacks
View all comments