First Magnetic Field Detection on a Class I Protostar

Abstract

Strong stellar magnetic fields are believed to truncate the inner accretion disks around young stars, redirecting the accreting material to the high latitude regions of the stellar surface. In the past few years, observations of strong stellar fields on T Tauri stars with field strengths in general agreement with the predictions of magnetospheric accretion theory have bolstered this picture. Currently, nothing is known about the magnetic field properties of younger, more embedded Class I young stellar objects (YSOs). It is believed that protostars accrete much of their final mass during the Class I phase, but the physics governing this process remains poorly understood. Here, we use high resolution near infrared spectra obtained with NIRSPEC on Keck and with Phoenix on Gemini South to measure the magnetic field properties of the Class I protostar WL 17. We find clear signatures of a strong stellar magnetic field. Analysis of this data suggests a surface average field strength of $2.9\pm 0.43$ kG on WL 17. We present our field measurements and discuss how they fit with the general model of magnetospheric accretion in young stars.

25 pages, 1 figure, accepted to ApJ

References in corpus (28)

• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• The Magnetic Fields of Classical T Tauri Stars
• Accretion-powered Stellar Winds as a Solution to the Stellar Angular Momentum Problem
• On the Evolutionary Status of Class I Stars and Herbig-Haro Energy Sources in Taurus-Auriga
• Near-Infrared Photometric Variability of Stars Toward the Orion A Molecular Cloud
• ISOCAM observations of the rho Ophiuchi cloud: Luminosity and mass functions of the pre-main sequence embedded cluster
• Magnetic field generation in fully convective rotating spheres
• Large-scale alpha^2-dynamo in low-mass stars and brown dwarfs
• Magnetospheric accretion on the T Tauri star BP Tauri
• Magnetic fields and accretion flows on the classical T Tauri star V2129 Oph
• Direct magnetic field detection in the innermost regions of an accretion disc
• The Physical Natures of Class I and Flat-Spectrum Protostellar Photospheres: A Near-Infrared Spectroscopic Study
• On the Distance to the Ophiuchus Star-Forming Region
• T Tauri stellar magnetic fields: He I measurements
• Testing the Reality of Strong Magnetic Fields on T Tauri Stars: The Naked T Tauri Star Hubble 4
• Measuring the Magnetic Field on the Classical T Tauri Star TW Hydrae
• Spectroscopic Detection of a Stellar-like Photosphere in an Accreting Protostar
• A Mid-Infrared Imaging Survey of Embedded Young Stellar Objects in the Rho Ophiuchi Cloud Core
• Stellar Properties of Pre-Main Sequence Stars from High Resolution Near-IR Spectra
• Magnetic Properties of Young Stars in the TW Hydrae Association
• Spectropolarimetry of the Classical T Tauri Star TW Hydrae
• Convective Dynamos and the Minimum X-ray Flux in Main Sequence Stars
• Extended Near-Infrared Emission from Candidate Protostars in the Taurus-Auriga Molecular Cloud
• The Angular Momentum Content and Evolution of Class I and Flat-Spectrum Protostars
• High Resolution Near-Infrared Spectra of Protostars
• Stellar and Circumstellar Properties of Class I Protostars
• Strong Dynamo Action in Rapidly Rotating Suns
• Convective intensification of magnetic flux tubes in stellar photospheres

Cited by in corpus (24)

• Target Selection for the SDSS-IV APOGEE-2 Survey
• Spin Evolution of Accreting Young Stars. I. Effect of Magnetic Star-Disk Coupling
• Magnetic-field measurements of T Tauri stars in the Orion Nebula cluster
• Characterizing TW Hydra
• SPIRou: a nIR spectropolarimeter / high-precision velocimeter for the CFHT
• Measuring the magnetic field of young stars using iSHELL observations: BP Tau and V347 Aur
• Rotational evolution of solar-type protostars during the star-disk interaction phase
• X-raying the Beating Heart of a Newborn Star: Rotational Modulation of High-energy Radiation from V1647 Ori
• The Mean Magnetic Field Strength of CI Tau
• Are the outflows in FU Orionis systems driven by the stellar magnetic field?
• The birth and early evolution of a low mass protostar
• Inferring possible magnetic field strength of accreting inflows in EXor-type objects from scaled laboratory experiments
• Ohmic heating of asteroids around magnetic stars
• Laboratory modeling of jets from young stars using plasma focus facilities
• Radio continuum observations of Class I protostellar disks in Taurus: constraining the greybody tail at centimetre wavelengths
• The Near Stellar Environment of Class 0 Protostars: A First Look with Near-Infrared Spectroscopy
• Time-dependent, long-term hydrodynamic simulations of the inner protoplanetary disk II: The importance of stellar rotation
• ALMA and VLA Observations of EX Lupi in its Quiescent State
• Birth of magnetized low-mass protostars and circumstellar disks
• AMI-LA radio continuum observations of Spitzer c2d small clouds and cores: Serpens region
• What governs the spin distribution of very young < 1 Myr low mass stars
• Vsini-s for late-type stars from spectral synthesis in K-band region
• Magnetic fields of Herbig Ae/Be stars
• Magnetic field measurements in a sample of Class I and flat-spectrum protostars observed with SPIRou