DG Tauri is a young star about 400

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s from the Earth. It is a T Tauri-type

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, ranging in brightness from

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10.5 to 14.9 (in blue light), making it far too faint to be seen with the

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DG Tauri is located in the Taurus molecular cloud. The star is close enough to the

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to be occasionally

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by the Moon, and observations of those events have shown that DG Tauri is a single star, although it may be part of a wide binary with DG Tauri B. The region around DG Tauri contains a variety of the structures associated with stars and planetary systems in the process of formation. In 1983, an optically visible jet extending up to 20

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(about 2500 AU) from the star was detected. The detection of continuum emission from a

circumstellar disk A Circumstellar disc (or circumstellar disk) is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the res ...

was announced in 1989. In 2022 a study was published showing that a streamer of gas is accreting onto the circumstellar disk.

Jet

The jet extending southwest (

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≈226°) from DG Tauri has been detected in X-rays, visible light, the infrared, and radio frequencies as low as 152 MHz. Its radiation is blue-shifted, indicating that the jet material is approaching us. It is inclined by about 38° to our line of sight. Density enhancements, or "knots", are seen in the jet, and their

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s can be measured. They are ejected from very near the star, moving at hundreds of kilometers per second, and the ejection velocity is positively correlated with the brightness of the star; when the star brightens, the knots move away from the star faster. When the star is bright, the knots are ejected from a region about 0.06 AU from the star. When the star is dimmer, the knots are launched from regions further from the star. About of material is ejected in this blue-shifted jet each year. A counter-jet (a red-shifted jet pointed in the direction opposite to the main jet) is seen in the

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X-ray image of the star.

Disk

The disk surrounding DG Tau has a nearly flat SED across the near-, mid- and much of the far-infrared, making it a

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I-II

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imaging of the disk shows it to be thin and smooth, with no substructures like the rings seen in HL Tauri or the spirals seen in HD 135344B. That suggests that planets have not yet formed. Combining the ALMA data from multiple frequencies allows the size of the dust grains to be estimated, if one adopts a model for grain

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. Using the DSHARP model results in an estimate of a typical grain size ranging from 400 microns in the inner 20 AU of the disk, increasing to >3 mm in the outer disk. Continuum emission from dust in the disk is detectable out to 80 AU from the star. At a distance of 30 AU from the star, the disk's

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is only 0.8 AU. Matter from the disk is accreting onto the star at a rate of about per year. Most of the light coming from DG Tauri arises from the release of energy as this material falls upon the star.

Streamer

DG Tauri is young enough that material from the star's natal cloud is still accreting onto the disk. The impact of such material hitting the disk can be detected by observing emission lines of sulfur-bearing molecules such as SO and SO₂, which are released when dust grains are destroyed by the

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at the point of impact. A "streamer" of such material has been detected. The streamer is a few hundred AU long, and is hitting the disk about 50 AU from the star.

References

{{Stars of Taurus Taurus (constellation) T Tauri stars Tauri, DG TIC objects Circumstellar disks