Catalog Description

For an object to be included in this database it must have a published, refereed, article that shows:

• spatially resolved scattered light, thermal continuum or line emission from the circumstellar disk, or,
• the presence of a shadowed dark lane from the disk midplane,

on which the outer disk radius can be measured.
Some of these objects include significant extended envelope emission. These are included only if the disk itself has been resolved as well. Objects whose resolved disk detection has been refuted are not included. For each object, the following information is provided:

Name

Commonly used name for the object. Click on the name to bring up detailed page on the object. Clicking on the 'Object' column header will allow you to reorder the table in alphabetical or reverse alphabetical order.

The information page on each object provides a table with the basic information for the star (coordinates, spectral type, distance) and the disk (position angle, disk inclination and reference for this information, when available). A list of published, refereed, references is also provided for each star. This list is not complete; references that provide information on the resolved disk or the unresolved disk at wavelengths longer than 1 micron are provided, along with theoretical/modelling papers that are specific to the object in question.

Spectral type

If known, the spectral type of the central star is provided. Clicking on the SpTy column header will re-sort the table in alphabetical or reverse alphabetical order.

Category

The stars are classified in the category column based on mass and age.

• TT = T Tauri star (typically < 2 solar masses)
• Hae = Herbig Ae or Be type star
• MS = star is on Main Sequence
• YSO = Object appears younger than TT or Hae stage in that it shows significant envelope emission
• Trans = A transition object
• PPN = protoplanetary nebula
• UC = The central star in these systems has either not been detected or has not yet been classified. This class largely consists of Orion proplyd objects in which the disk silhouette is resolved

Clicking on the Category column header will re-sort the table in alphabetical or reverse alphabetical order, showing all objects in the same category together.

Distance

The distance, in parsec, either to the star or star forming region the star is in, is provided. Clicking on the Distance column header will re-sort the table in either increasing or decreasing distance.

Disk Diameter

For a specific wavelength (listed in the last column of the table) the diameter of the resolved emission is provided, in both arcsec and AU (if the distance is known).The extent of disk emission can vary significantly depending on whether you are observing scattered light or mm line emission; we provide the largest measurement available for each disk, the reference to which is highlighted with an asterisk on the object details page. Clicking on the Disk diameter column header will re-sort the table in either increasing or decreasing disk size.

Inclination

The inclination angle of the disk is provided when it has been calculated in the literature; in some cases this value is model dependent. We define inclination to be the angle between the line of sight and the normal to the disk plane, i.e., face-on disks have i = 0, whereas edge-on disks have i = 90 degrees. Where necessary, measurements in the literature have been converted to this definition. Clicking on the inclination column header will re-sort the table in either increasing or decreasing inclination angle.

How well resolved

This measurement provides a rough quantification of how well resolved each disk is. Taking the disk diameter at the reference wavelength listed (last column in table), the number of diffraction beams that can fit in the disk diameter is calculated. Clicking on the column header will re-sort the table in either increasing or decreasing inclination angle.
Note, this is highly dependent on the wavelength of observation. The extent of disk emission can vary significantly depending on whether you are observing scattered light or mm line emission.

At ref. wavelength

Lists the wavelength at which the disk diameter and 'how well resolved' columns are calculated. The publication which provided the disk size is highlighted by an asterisk on the object details page.

How often is this catalog updated?

Newly resolved disks will be added as we become aware of them. You can help by pro-actively sending your object and journal citation to us. References for each object will be updated at least quarterly.