First Detection of Submillimeter Polarization from T Tauri Stars

We report a first detection of polarization of the 850 μm continuum emission from two T Tauri stars (TTSs), GM Aur and DG Tau. These are both single and classical TTSs. The emission mostly comes from the compact (r < 100 AU) accretion disks. The polarization (at ~3% level at 3 σ) is interpreted in terms of thermal emission by magnetically aligned dust grains in the disk. Thus these submillimeter polarizations probe the magnetic field structure in the disk, while the previously reported millimeter/submillimeter polarizations of protostars and the transitional objects from the protostars to TTSs trace the magnetic fields in the larger envelope region. In both TTSs, the direction of the magnetic field inferred from our submillimeter polarizations is parallel to the plane of the compact dust disk measured by interferometric observations, suggesting the dominance of a toroidal magnetic field component in the disk. The magnetic evolution of the circumstellar environments is discussed, as well as the constraints on the MHD models of the jets and outflows from young stellar objects.

[1]  M. Hayashi,et al.  Observations of 11 protostellar sources in Taurus with Nobeyama millimeter array - Growth of circumstellar disks , 1991 .

[2]  E. Feigelson,et al.  Observations of X-ray emission from T Tauri stars , 1980 .

[3]  Giles A Novak,et al.  Detection of submillimeter polarization in the Orion nebula , 1984 .

[4]  R. Kawabe,et al.  Aperture Synthesis 13CO (J = 1-0) Observations of the Molecular Gas around DG Tauri: Evidence for a Dispersing Gas Disk , 1996 .

[5]  M. Tamura,et al.  Infrared polarimetry of dark clouds – I. Magnetic field structure in Heiles Cloud 2 , 1987 .

[6]  B. Reipurth,et al.  Herbig-Haro flows and the birth of low mass stars : proceedings of the 182nd Symposium of the International Astronomical Union, held in Chamonix, France, 20-26 January 1997 , 1997 .

[7]  S. Cabrit,et al.  Forbidden-line emission and infrared excesses in T Tauri stars - Evidence for accretion-driven mass loss? , 1990 .

[8]  Vincent Mannings,et al.  Dust in discs around T Tauri stars : grain growth ? , 1994 .

[9]  L. Prato,et al.  Disk Dissipation in Single and Binary Young Star Systems in Taurus , 1995 .

[10]  R. Mundt,et al.  Jets from young stars , 1983 .

[11]  Kazunari Shibata,et al.  Magnetically Driven Jets from Accretion Disks. I. Steady Solutions and Application to Jets/Winds in Young Stellar Objects , 1997 .

[12]  Martin G. Cohen,et al.  Observational studies of pre-main-sequence evolution. , 1979 .

[13]  J. Najita,et al.  Mass loss from rapidly rotating magnetic protostars , 1988 .

[14]  M. Tamura,et al.  Circumprotostellar environments. 2: Envelopes, activity, and evolution , 1994 .

[15]  P. Andre',et al.  The Contribution of Disks and Envelopes to the Millimeter Continuum Emission from Very Young Low-Mass Stars , 1993 .

[16]  A. Dutrey,et al.  Disks and Outflows as Seen from the IRAM Interferometer , 1997 .

[17]  W. Cudlip,et al.  Far infrared polarimetry of W51A and M42 , 1982 .

[18]  Charles J. Lada,et al.  The disks of T Tauri stars with flat infrared spectra , 1987 .

[19]  Hilo,et al.  SCUBA: A Common - user submillimetre camera operating on the James Clerk Maxwell telescope , 1998, astro-ph/9809122.

[20]  D. W. Koerner,et al.  Imaging the Small-Scale Circumstellar Gas Around T~Tauri Stars , 1995 .

[21]  A. M. Flett,et al.  First results from a submillimetre polarimeter on the James Clerk Maxwell Telescope , 1991 .

[22]  John E. Carlstrom,et al.  Magnetic Field Structure in Protostellar Envelopes , 1997 .

[23]  C. Bertout.  T Tauri Stars: Wild as Dust , 1989 .

[24]  D. Clemens,et al.  Magnetic Fields in Massive Cloud Cores: Comparison of MILLIPOL and IRAS Results , 1993 .

[25]  R. Kawabe,et al.  Imaging of the Compact Dust Disk around DG Tauri with 1'' Resolution , 1996 .

[26]  K. Shibata,et al.  Magnetically Driven Jets from Accretion Disks. II. Nonsteady Solutions and Comparison with Steady Solutions , 1997 .

[27]  J. Elias.  A study of the Taurus dark cloud complex , 1978 .

[28]  Colin Norman,et al.  Bipolar hydromagnetic winds from disks around protostellar objects , 1986 .

[29]  W. Holland,et al.  Submillimeter Polarimetry of Class 0 Protostars: Constraints on Magnetized Outflow Models , 1997 .

[30]  S. Beckwith,et al.  A Survey for Circumstellar Disks around Young Stellar Objects , 1990 .

[31]  P. Andre',et al.  From T Tauri stars to protostars: Circumstellar material and young stellar objects in the rho Ophiuchi cloud , 1994 .

[32]  H. Berk,et al.  Magnetically driven jets and winds , 1991 .

[33]  J. Hough,et al.  1 Millimeter Polarimetry of Young Stellar Objects: Low-Mass Protostars and T Tauri Stars , 1995 .

[34]  G. Fuller,et al.  Submillimeter photometry and disk masses of T Tauri disk systems , 1990 .

[35]  Michael F. Skrutskie,et al.  Circumstellar Material Associated with Solar-Type Pre-Main-Sequence Stars: A Possible Constraint on the Timescale for Planet Building , 1989 .

[36]  S. Beckwith,et al.  A rotating gaseous disk around the T Tauri star GM Aurigae , 1992 .