Light curves for DG Tauri. The upper panel, adapted from Pyo et al. (2024),[9] shows the long term variability, and the lower panel, plotted fromTESS data,[10] shows the short term variability. The 6.30 day rotation period[7][11] is marked in red.
DG Tauri is located in theTaurus molecular cloud. The star is close enough to theecliptic to be occasionallyocculted 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 withDG Tauri B.[12][3]
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 visiblejet extending up to 20arc seconds (about 2500AU) from the star was detected.[13][14] The detection of continuum emission from acircumstellar disk was announced in 1989.[15] In 2022 a study was published showing that a streamer of gas isaccreting onto the circumstellar disk.[16]
The jet extending southwest (position angle ≈226°)[17] from DG Tauri has been detected in X-rays, visible light, the infrared, and radio frequencies as low as 152 MHz.[18][9][19] Its radiation isblue-shifted, indicating that the jet material is approaching us.[20] It is inclined by about 38° to our line of sight.[21] Density enhancements, or "knots", are seen in the jet, and theirproper motions 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.[9] About(8±4)×10−9M☉ of material is ejected in this blue-shifted jet each year.[21]
A counter-jet (a red-shifted jet pointed in the direction opposite to the main jet) is seen in theChandra X-ray image of thestar.[18]
The disk surrounding DG Tau has a nearly flatSED across thenear-, mid- and much of the far-infrared,[22] making it aclass I-IIprotostar.[23]ALMA imaging of the disk shows it to be thin and smooth, with no substructures like the rings seen inHL Tauri or the spirals seen in HD 135344B.[24] 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 grainemissivity. Using the DSHARP model[25] 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'sscale height is only 0.8 AU.[23]
Matter from the disk isaccreting onto the star at a rate of about1×10−7M☉ per year.[26] Most of the light coming from DG Tauri arises from the release of energy as this material falls upon the star.[27]
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 theshock at the point of impact. A "streamer" of such material has been detected.[16] The streamer is a few hundred AU long, and is hitting the disk about 50 AU from the star.[28]
^abcdefSemenov, D.; Henning, Th.; Guilloteau, S.; Smirnov-Pinchukov, G.; Dutrey, A.; Chapillon, E.; Piétu, V.; Franceschi, R.; Schwarz, K.; van Terwisga, S.; Bouscasse, L.; Caselli, P.; Ceccarelli, C.; Cunningham, N.; Fuente, A.; Gieser, C.; Hsieh, T.-H.; Lopez-Sepulcre, A.; Segura-Cox, D. M.; Pineda, J. E.; Maureira, M. J.; Möller, Th.; Tafalla, M.; Valdivia-Mena, M. T. (May 2024). "PRODIGE - planet-forming disks in Taurus with NOEMA. I. Overview and first results for 12CO, 13CO, and C18O".Astronomy & Astrophysics.685: A126.arXiv:2402.14653.Bibcode:2024A&A...685A.126S.doi:10.1051/0004-6361/202346465.
^abSamus, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General Catalogue of Variable Stars: Version GCVS 5.1".Astronomy Reports.61 (1):80–88.Bibcode:2017ARep...61...80S.doi:10.1134/S1063772917010085.
^"DG Tau".The International Variable Star Index. AAVSO. Retrieved24 March 2025.
^Kitamura, Yoshimi; Kawabe, Ryohei; Saito, Masao (July 1996). "Imaging of the Compact Dust Disk around DG Tauri with 1" Resolution".Astrophysical Journal Letters.465:L137 –L140.Bibcode:1996ApJ...465L.137K.doi:10.1086/310152.
^abGarufi, A.; Podio, L.; Codella, C.; Segura-Cox, D.; Vander Donckt, M.; Mercimek, S.; Bacciotti, F.; Fedele, D.; Kasper, M.; Pineda, J. E.; Humphreys, E.; Testi, L. (February 2022). "ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT). VI. Accretion shocks in the disk of DG Tau and HL Tau".Astronomy & Astrophysics.658: A104.arXiv:2110.13820.Bibcode:2022A&A...658A.104G.doi:10.1051/0004-6361/202141264.
^Stolker, T.; Dominik, C.; Avenhaus, H.; Min, M.; de Boer, J.; Ginski, C.; Schmid, H. M.; Juhasz, A.; Bazzon, A.; Waters, L. B. F. M.; Garufi, A.; Augereau, J.-C.; Benisty, M.; Boccaletti, A.; Henning, Th.; Langlois, M.; Maire, A. -L.; Ménard, F.; Meyer, M. R.; Pinte, C.; Quanz, S. P.; Thalmann, C.; Beuzit, J. -L.; Carbillet, M.; Costille, A.; Dohlen, K.; Feldt, M.; Gisler, D.; Mouillet, D.; Pavlov, A.; Perret, D.; Petit, C.; Pragt, J.; Rochat, S.; Roelfsema, R.; Salasnich, B.; Soenke, C.; Wildi, F. (November 2016)."Shadows cast on the transition disk of HD 135344B. Multiwavelength VLT/SPHERE polarimetric differential imaging"(PDF).Astronomy & Astrophysics.595: A113.arXiv:1603.00481.Bibcode:2016A&A...595A.113S.doi:10.1051/0004-6361/201528039. Retrieved27 March 2025.
