Astronomy:DG Tauri

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Short description: Star in constellation Taurus
DG Tauri
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An artist's conception of DG Tauri, showing the star, disk and jet.[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Taurus
Right ascension  04h 27m 04.6921s[2]
Declination 26° 06′ 16.0602″[2]
Characteristics
Spectral type K7[3]
Variable type T Tau[4]
Astrometry
Radial velocity (Rv)5.5[3] km/s
Proper motion (μ) RA: +5.514[2] mas/yr
Dec.: −20.478[2] mas/yr
Parallax (π)7.9836 ± 0.1182[2] mas
Distance409 ± 6 ly
(125 ± 2 pc)
Details
Mass0.70[3] M☉
Radius1.9[5] R☉
Luminosity0.26[3] L☉
Surface gravity (log g)3.20[6] cgs
Temperature4,000[3] K
Metallicity [Fe/H]−1.49[2] dex
Rotation6.3 days[7]
Rotational velocity (v sin i)26.9[6] km/s
Age1[8] Myr
Other designations
2MASS J04270469+2606163, IRAS 04240+2559, Gaia DR3 151262700852297728, TIC 268017134, AAVSO 0420+25B, HH 158
Database references
SIMBADdata

DG Tauri is a young star about 400 light years from the Earth. It is a T Tauri-type variable star, ranging in brightness from magnitude 10.5 to 14.9 (in blue light), making it far too faint to be seen with the naked eye.[4]

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 from TESS data,[10] shows the short term variability. The 6.30 day rotation period[7][11] is marked in red.

DG Tauri is located in the Taurus molecular cloud. The star is close enough to the ecliptic to be occasionally occulted 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.[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 visible jet extending up to 20 arc seconds (about 2500 AU) from the star was detected.[13][14] The detection of continuum emission from a circumstellar disk was announced in 1989.[15] In 2022 a study was published showing that a streamer of gas is accreting onto the circumstellar disk.[16]

Jet

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 is blue-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 their proper 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)×10−9 M☉ 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 the Chandra X-ray image of the star.[18]

Disk

The disk surrounding DG Tau has a nearly flat SED across the near-, mid- and much of the far-infrared,[22] making it a class I-II protostar.[23] ALMA 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.[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 grain emissivity. 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's scale height is only 0.8 AU.[23]

Matter from the disk is accreting onto the star at a rate of about 1×10−7 M☉ 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]

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 shock 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]

Possible planetary-mass companion

In 2017, it was found that the rogue planet or sub-brown dwarf designated KPNO-Tau 4 may be gravitationally associated to the DG Tauri system.[29][30] If KPNO-Tau 4 is gravitationally associated to the system, it would orbit the star on a wide, long 66,000 astronomical unit orbit.[29]

The DG Tauri planetary system[29][30]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(years) 		Eccentricity Inclination Radius
b 10 MJ 65,694 — — — 4.2 RJ

References

  1. ↑ "DG Tau: Energetic Jets from a Budding Solar System". Harvard. https://chandra.harvard.edu/photo/2008/dgtau/index.html. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Semenov, D.; Henning, Th.; Guilloteau, S.; Smirnov-Pinchukov, G.; Dutrey, A.; Chapillon, E.; Piétu, V.; Franceschi, R. et al. (May 2024). "PRODIGE - planet-forming disks in Taurus with NOEMA. I. Overview and first results for 12CO, 13CO, and C18O". Astronomy & Astrophysics 685: A126. doi:10.1051/0004-6361/202346465. Bibcode: 2024A&A...685A.126S. 
  4. ↑ 4.0 4.1 Samus, 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. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S. 
  5. ↑ Manzo-Martínez, Ezequiel; Calvet, Nuria; Hernández, Jesús; Lizano, Susana; Hernández, Ramiro Franco; Miller, Christopher J.; Maucó, Karina; Briceño, César et al. (2020). "The Evolution of the Inner Regions of Protoplanetary Disks". The Astrophysical Journal 893 (1): 56. doi:10.3847/1538-4357/ab7ead. Bibcode: 2020ApJ...893...56M. 
  6. ↑ 6.0 6.1 López-Valdivia, Ricardo; Sokal, Kimberly R.; Mace, Gregory N.; Kidder, Benjamin T.; Hussaini, Maryam; Nofi, Larissa; Prato, L.; Johns-Krull, Christopher M. et al. (2021). "The IGRINS YSO Survey. I. Stellar Parameters of Pre-main-sequence Stars in Taurus-Auriga". The Astrophysical Journal 921 (1): 53. doi:10.3847/1538-4357/ac1a7b. Bibcode: 2021ApJ...921...53L. 
  7. ↑ 7.0 7.1 Percy, John R.; Grynko, Sergiy; Seneviratne, Rajiv; Herbst, William (July 2010). "Self-Correlation Analysis of the Photometric Variability of T Tauri Stars. II. A Survey". Publications of the Astronomical Society of the Pacific 122 (893): 753–765. doi:10.1086/654826. Bibcode: 2010PASP..122..753P. https://iopscience.iop.org/article/10.1086/654826/pdf. Retrieved 28 March 2025. 
  8. ↑ Ward-Duong, K.; Patience, J.; Bulger, J.; Van Der Plas, G.; Ménard, F.; Pinte, C.; Jackson, A. P.; Bryden, G. et al. (2018). "The Taurus Boundary of Stellar/Substellar (TBOSS) Survey. II. Disk Masses from ALMA Continuum Observations". The Astronomical Journal 155 (2): 54. doi:10.3847/1538-3881/aaa128. Bibcode: 2018AJ....155...54W. 
  9. ↑ 9.0 9.1 9.2 Pyo, Tae-Soo; Hayashi, Masahiko; Takami, Michihiro; Beck, Tracy L. (March 2024). "Ejection Patterns in the DG Tau Jet over the Last 40 yr: Insights into Mass Accretion Variability". The Astrophysical Journal 963 (2): 159. doi:10.3847/1538-4357/ad1f59. Bibcode: 2024ApJ...963..159P. 
  10. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  11. ↑ "DG Tau". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=35147. 
  12. ↑ 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. doi:10.1086/310152. Bibcode: 1996ApJ...465L.137K. 
  13. ↑ Mundt, R.; Fried, J. W. (November 1983). "Jets from young stars". Astrophysical Journal 274: L83–L86. doi:10.1086/184155. Bibcode: 1983ApJ...274L..83M. 
  14. ↑ Oh, Heeyoung; Pyo, Tae-Soo; Yuk, In-Soo; Park, Byeong-Gon (2015). "Long-slit Spectroscopy of Parsec-scale Jets From DG Tauri". Journal of the Korean Astronomical Society 48 (2): 113–123. doi:10.5303/JKAS.2015.48.2.113. Bibcode: 2015JKAS...48..113O. 
  15. ↑ Sargent, Anneila I.; Beckwith, Steven V. W. (1989). "Molecular disks around young stars". Structure and Dynamics of the Interstellar medium. Lecture Notes in Physics. 350. pp. 215–220. doi:10.1007/BFb0114869. ISBN 978-3-540-51956-0. Bibcode: 1999alma.confE..15D. 
  16. ↑ 16.0 16.1 Garufi, A.; Podio, L.; Codella, C.; Segura-Cox, D.; Vander Donckt, M.; Mercimek, S.; Bacciotti, F.; Fedele, D. et al. (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. doi:10.1051/0004-6361/202141264. Bibcode: 2022A&A...658A.104G. 
  17. ↑ Liu, Chun-Fan; Shang, Hsien; Herczeg, Gregory J.; Walter, Frederick M. (December 2016). "The [Ne III] Jet of DG Tau and its Ionization Scenarios". The Astrophysical Journal 832 (2): 153. doi:10.3847/0004-637X/832/2/153. Bibcode: 2016ApJ...832..153L. 
  18. ↑ 18.0 18.1 Güdel, M.; Skinner, S. L.; Audard, M.; Briggs, K. R.; Cabrit, S. (February 2008). "Discovery of a bipolar X-ray jet from the T Tauri star DG Tauri". Astronomy and Astrophysics 478 (3): 797–807. doi:10.1051/0004-6361:20078141. Bibcode: 2008A&A...478..797G. https://www.aanda.org/articles/aa/pdf/2008/06/aa8141-07.pdf. Retrieved 26 March 2025. 
  19. ↑ Feeney-Johansson, Anton; Purser, Simon J. D.; Ray, Tom P.; Eislöffel, Jochen; Hoeft, Matthias; Drabent, Alexander; Ainsworth, Rachael E. (November 2019). "The First Detection of a Low-frequency Turnover in Nonthermal Emission from the Jet of a Young Star". The Astrophysical Journal Letters 885 (1): L7. doi:10.3847/2041-8213/ab4b56. Bibcode: 2019ApJ...885L...7F. 
  20. ↑ Takami, Michihiro; Günther, Hans Moritz; Schneider, P. Christian; Beck, Tracy L.; Karr, Jennifer L.; Ohyama, Youichi; Galván-Madrid, Roberto; Uyama, Taichi et al. (January 2023). "Time-variable Jet Ejections from RW Aur A, RY Tau, and DG Tau". The Astrophysical Journal Supplement Series 264 (1): 1. doi:10.3847/1538-4365/ac9afc. Bibcode: 2023ApJS..264....1T. 
  21. ↑ 21.0 21.1 Maurri, L.; Bacciotti, F.; Podio, L.; Eislöffel, J.; Ray, T. P.; Mundt, R.; Locatelli, U.; Coffey, D. (May 2014). "Physical properties of the jet from DG Tauri on sub-arcsecond scales with HST/STIS". Astronomy & Astrophysics 565: A110. doi:10.1051/0004-6361/201117510. Bibcode: 2014A&A...565A.110M. https://www.aanda.org/articles/aa/pdf/2014/05/aa17510-11.pdf. Retrieved 26 March 2025. 
  22. ↑ Garufi, A.; Ginski, C.; van Holstein, R. G.; Benisty, M.; Manara, C. F.; Pérez, S.; Pinilla, P.; Ribas, Á. et al. (May 2024). "The SPHERE view of the Taurus star-forming region. The full census of planet-forming disks with GTO and DESTINYS programs". Astronomy & Astrophysics 685: A53. doi:10.1051/0004-6361/202347586. Bibcode: 2024A&A...685A..53G. https://www.aanda.org/articles/aa/pdf/2024/05/aa47586-23.pdf. Retrieved 26 March 2025. 
  23. ↑ 23.0 23.1 Ohashi, Satoshi; Momose, Munetake; Kataoka, Akimasa; Higuchi, Aya E; Tsukagoshi, Takashi; Ueda, Takahiro; Codella, Claudio; Podio, Linda et al. (September 2023). "Dust Enrichment and Grain Growth in a Smooth Disk around the DG Tau Protostar Revealed by ALMA Triple Bands Frequency Observations". The Astrophysical Journal 954 (2): 110. doi:10.3847/1538-4357/ace9b9. Bibcode: 2023ApJ...954..110O. 
  24. ↑ Stolker, T.; Dominik, C.; Avenhaus, H.; Min, M.; de Boer, J.; Ginski, C.; Schmid, H. M.; Juhasz, A. et al. (November 2016). "Shadows cast on the transition disk of HD 135344B. Multiwavelength VLT/SPHERE polarimetric differential imaging". Astronomy & Astrophysics 595: A113. doi:10.1051/0004-6361/201528039. Bibcode: 2016A&A...595A.113S. https://www.aanda.org/articles/aa/pdf/2016/11/aa28039-15.pdf. Retrieved 27 March 2025. 
  25. ↑ Birnstiel, Tilman; Dullemond, Cornelis P.; Zhu, Zhaohuan; Andrews, Sean M.; Bai, Xue-Ning; Wilner, David J.; Carpenter, John M.; Huang, Jane et al. (December 2018). "The Disk Substructures at High Angular Resolution Project (DSHARP). V. Interpreting ALMA Maps of Protoplanetary Disks in Terms of a Dust Model". The Astrophysical Journal Letters 869 (2): L45. doi:10.3847/2041-8213/aaf743. Bibcode: 2018ApJ...869L..45B. 
  26. ↑ Agra-Amboage, V.; Dougados, C.; Cabrit, S.; Reunanen, J. (August 2011). "Sub-arcsecond [Fe ii spectro-imaging of the DG Tauri jet. Periodic bubbles and a dusty disk wind?"]. Astronomy & Astrophysics 532: A59. doi:10.1051/0004-6361/201015886. Bibcode: 2011A&A...532A..59A. https://www.aanda.org/articles/aa/pdf/2011/08/aa15886-10.pdf. Retrieved 28 March 2025. 
  27. ↑ Hartigan, Patrick; Kenyon, Scott J.; Hartmann, Lee; Strom, Stephen E.; Edwards, Suzan; Welty, Alan D.; Stauffer, John (December 1991). "Optical Excess Emission in T Tauri Stars". Astrophysical Journal 382: 617–635. doi:10.1086/170749. Bibcode: 1991ApJ...382..617H. https://articles.adsabs.harvard.edu/pdf/1991ApJ...382..617H. Retrieved 28 March 2025. 
  28. ↑ Hanawa, Tomoyuki; Garufi, Antonio; Podio, Linda; Codella, Claudio; Segura-Cox, Dominique (March 2024). "Cloudlet capture model for the accretion streamer onto the disc of DG Tau". Monthly Notices of the Royal Astronomical Society 528 (4): 6581–6592. doi:10.1093/mnras/stae338. Bibcode: 2024MNRAS.528.6581H. https://ui.adsabs.harvard.edu/link_gateway/2024MNRAS.528.6581H/PUB_PDF. Retrieved 29 March 2025. 
  29. ↑ 29.0 29.1 29.2 Joncour, Isabelle (2017). "Multiplicity and clustering in Taurus star-forming region. I. Unexpected ultra-wide pairs of high-order multiplicity in Taurus". NASA ADS. https://ui.adsabs.harvard.edu/abs/2017A%26A...599A..14J/abstract. Retrieved 2026-01-27. 
  30. ↑ 30.0 30.1 Kraus, Adam (2006). "Multiplicity and Optical Excess across the Substellar Boundary in Taurus". NASA ADS. https://ui.adsabs.harvard.edu/abs/2006ApJ...649..306K/abstract. Retrieved 2026-01-27. 



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