Key Takeaways
1. Protoplanetary disks form as stars attract gas and dust from their surroundings, contributing to star growth and potential planet formation.
2. In visible light images, protoplanetary disks appear as dark dust disks against bright reflection nebulae, with jets of gas also visible.
3. Infrared observations reveal stars in earlier developmental phases, hidden by thick dust envelopes that visible light cannot penetrate.
4. The protoplanetary disks cast shadows on surrounding clouds, making them appear larger in infrared images.
5. The observed stars are located in different molecular clouds, with distances ranging from 450 to 1,500 light-years from Earth.
This Hubble collection shows eight protoplanetary disks, with four captured in visible light and four in infrared. As stars are being formed, they attract gas and dust from their surroundings. Some of this material creates a spinning disk known as a protoplanetary disk. The gas and dust within this disk continue to supply the growing star, while the leftover matter may eventually give rise to planets.
Visible Light Observations
In the visible light image presented, the protoplanetary disks appear as dark dust disks amidst the bright light. HH 390 is not seen edge-on, which is the reason why its disk looks like it’s at the edge of the bright area. The bright light that is being referred to is a reflection nebula, which is a zone of gas and dust illuminated by a star’s light. You can also see jets of gas in the image. Both HH 390 and Tau 042021 are located around 450 light-years away in the Taurus Molecular Cloud, while the stars at the bottom are nearly 500 light-years distant in the Chameleon I star-forming region.
Infrared Insights
The stars seen in the infrared image seem to be at earlier phases of their development than those in the visible light photo. During these earlier stages, stars are shrouded by a thick dust envelope. Infrared light can penetrate this envelope, whereas visible light cannot, which explains why the envelope is not visible in the light images.
The dark regions that are centered in the bright light are indeed the protoplanetary disks. The shadows cast by the disks on the surrounding clouds make them appear larger than they really are. The stars located at the top right and bottom left are situated in the Orion Molecular Cloud, approximately 1,300 light-years from us. The stars in the top left and bottom right are found in the Perseus Molecular Cloud, about 1,500 light-years away.
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