These are Hubble Space Telescope images of four newly discovered protoplanetary disks around young stars in the Orion nebula, located 1,500 light-years away. Gas and dust disks, long suspected by astronomers to be an early stage of planetary formation, can be directly seen in visible light by Hubble.
Disks around young stars (also known as circumstellar or protoplanetary disks) are thought to be made up of 99% gas and 1% dust. Even that small amount of dust is enough to make the disks opaque and dark at visible wavelengths. The dark disks are seen in these images because they are silhouetted against the bright backdrop of the hot gas of the Orion nebula.
The red glow in the center of each disk is a young, newly formed star, roughly one million years old (compared to the 4.5 billion year age of the Sun). The stars range in mass from 30% to 150% of the mass of our own Sun. As they evolve, the disks may go on to form planetary systems like our own. While only a handful of these dark silhouette disks have been discovered so far, they seem to belong to a much larger family of similar objects, and current indications are that protoplanetary disks are common in the Orion nebula.
Mark McCaughrean of the Max-Planck-Institute for Astronomy, Heidelberg, Germany, and his collaborator C. Robert O'Dell from Rice University, Houston, Texas, spotted the new disks in large-scale survey images of the Orion nebula that O'Dell had taken with Hubble between January 1994 and March 1995. A detailed study of the disk images has been submitted for publication to the Astronomical Journal.
Each image is 167 billion miles, or 257 billion kilometers, across (30 times the diameter of our own solar system). The disks range in size from two to eight times the diameter of our solar system. The researchers explain the different circular or elliptical shapes as being due to the fact that each disk is tilted toward Earth by different degrees.
Each picture is a composite of three images taken with Hubble's Wide Field and Planetary Camera 2, through narrow-band filters which admit the light of emission lines of ionized oxygen (represented here by blue), hydrogen (green), and nitrogen (red). The hot gas of the background Orion nebula emits strongly at each of these wavelengths, providing a strong backdrop for the disks to be silhouetted against. In each case, the central star is also clearly visible.
Credits
Mark McCaughrean (Max-Planck-Institute for Astronomy), C. Robert O'Dell (Rice University), and NASA| About The Object | |
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| Object Name | Orion Nebula, M42, NGC 1976 |
| R.A. Position | 05h 35m 17.29s |
| Dec. Position | -5° 23' 27.99" |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
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| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
