Chandra
Orion Ultradeep Project
X-rays and proplyds
The Hubble Space Telescope has directly imaged dusty protoplanetary disks (nicknamed proplyds) around Orion Nebula, seen in silhouette against the bright nebula. The images show the disks in various stages of evaporation by the intense radiation of the massive Trapezium OB stars. COUP provides a new view of host stars of proplyds and confirms the irradiation of the disk by stellar X-rays. 70% of ~140 proplyds are detected by Chandra, including many that do not display central stars in HST images.
Hubble sees disks at various orientations; above is a Hubble image of an edge-on disks where the small circle showing the location of the COUP X-ray source. The plot above shows that the X-ray spectra show increased soft X-ray absorption in edge-on disks. This is important for two reasons: it is the first measure of the gas (rather than dust) content of Orion proplyds, and it a direct measure that X-rays are being absorbed (and thus must ionize) disk gas. Ionization of disk gas may critically alter its behavior (e.g. turbulent vs. smooth motions) and the processes of planet formation.
One remarkable Orion star is nicknamed the Beehive. In Hubble images (above left), we see the bright star, dark disk, collimated jet, and bow shock between the evaporating disk and OB starlight. The Chandra spectrum (above right) is unique among the 1616 COUP sources, showing a hard flaring component from the star and an ultrasoft component from the jet.
The full paper on COUP X-rays and proplyds is:
X-ray Emission from Orion Nebula Cluster Stars with Circumstellar Disks and Jets
Joel H. Kastner, Geoffrey Franz, Nicolas Grosso, John Bally, Mark J. McCaughrean, Konstantin Getman, Eric D. Feigelson, Norbert S. Schulz
Back to the COUP home page
X-rays and proplyds
The Hubble Space Telescope has directly imaged dusty protoplanetary disks (nicknamed proplyds) around Orion Nebula, seen in silhouette against the bright nebula. The images show the disks in various stages of evaporation by the intense radiation of the massive Trapezium OB stars. COUP provides a new view of host stars of proplyds and confirms the irradiation of the disk by stellar X-rays. 70% of ~140 proplyds are detected by Chandra, including many that do not display central stars in HST images.
Hubble sees disks at various orientations; above is a Hubble image of an edge-on disks where the small circle showing the location of the COUP X-ray source. The plot above shows that the X-ray spectra show increased soft X-ray absorption in edge-on disks. This is important for two reasons: it is the first measure of the gas (rather than dust) content of Orion proplyds, and it a direct measure that X-rays are being absorbed (and thus must ionize) disk gas. Ionization of disk gas may critically alter its behavior (e.g. turbulent vs. smooth motions) and the processes of planet formation.
One remarkable Orion star is nicknamed the Beehive. In Hubble images (above left), we see the bright star, dark disk, collimated jet, and bow shock between the evaporating disk and OB starlight. The Chandra spectrum (above right) is unique among the 1616 COUP sources, showing a hard flaring component from the star and an ultrasoft component from the jet.
The full paper on COUP X-rays and proplyds is:
X-ray Emission from Orion Nebula Cluster Stars with Circumstellar Disks and Jets
Joel H. Kastner, Geoffrey Franz, Nicolas Grosso, John Bally, Mark J. McCaughrean, Konstantin Getman, Eric D. Feigelson, Norbert S. Schulz
Back to the COUP home page