A warped disk around an infant protostar

ABSTRACT Recent exoplanet studies have revealed that the orbital planes of planets are not always aligned with one another or with the equatorial plane of the central star. The misalignment

has been ascribed to gravitational scattering by giant planets and/or companion stars1,2,3 or to fly-bys in stellar cluster environments4. Alternatively, the misalignment could be natal:

that is, such planets were born in a warped protostellar disk5,6. Warped disk structures have been reported in some transition disks and protoplanetary disks7,8, but not in the earlier

stages of protostar evolution, although such a possibility is suggested by outflow morphology9,10. Here we report millimetre-wavelength dust continuum observations of the young embedded

protostar IRAS 04368+2557 in the protostellar core L1527 at a distance11 of 137 parsecs; the protostar’s disk is almost edge-on12,13,14,15,16. The inner and outer parts of the disk have

slightly different orbital planes, connected at 40 to 60 astronomical units from the star, but the disk has point symmetry with respect to the position of the protostar. We interpret it as a

warped disk that is rotationally supported. Because there is no evidence for a companion source17,18, the warped structure must be due to either anisotropic accretion of gas with different

rotational axes, or misalignment of the rotation axis of the disk with the magnetic field direction. Access through your institution Buy or subscribe This is a preview of subscription

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about institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS GRAVITATIONAL INSTABILITY IN A PLANET-FORMING DISK Article 04 September

2024 FOUR ANNULAR STRUCTURES IN A PROTOSTELLAR DISK LESS THAN 500,000 YEARS OLD Article 07 October 2020 A PROTOSTELLAR SYSTEM FED BY A STREAMER OF 10,500 AU LENGTH Article 27 July 2020 DATA

AVAILABILITY This work used the following ALMA data whose codes are ADS/JAO.ALMA #2013.0.00858.S and ADS/JAO.ALMA #2013.1.01086.S for the 0.9-mm and 1.3-mm observations, respectively. The

data are available at https://almascience.nao.ac.jp/aq by setting the observation codes. The data sets generated or analysed during this study are available from the corresponding author on

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geometries using shadows in transitional disks. _Astron. Astrophys_. 604, L10 (2017). Article  ADS  Google Scholar  Download references ACKNOWLEDGEMENTS We thank Y. Suto, C. Chandler, Y.

Aikawa, C. Ceccarelli and B. Lefloch for valuable discussions. This Letter makes use of ALMA data. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan),

together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.

This work was supported by JSPS KAKENHI grants 25108005, 16H03964 and 18H05222. REVIEWER INFORMATION _Nature_ thanks C. Codella and the other anonymous reviewer(s) for their contribution to

the peer review of this work. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * RIKEN Cluster for Pioneering Research, Saitama, Japan Nami Sakai, Yichen Zhang, Aya E. Higuchi & Satoshi

Ohashi * Center for Frontier Science, Chiba University, Chiba, Japan Tomoyuki Hanawa * Department of Physics, The University of Tokyo, Tokyo, Japan Yoko Oya & Satoshi Yamamoto Authors *

Nami Sakai View author publications You can also search for this author inPubMed Google Scholar * Tomoyuki Hanawa View author publications You can also search for this author inPubMed Google

Scholar * Yichen Zhang View author publications You can also search for this author inPubMed Google Scholar * Aya E. Higuchi View author publications You can also search for this author

inPubMed Google Scholar * Satoshi Ohashi View author publications You can also search for this author inPubMed Google Scholar * Yoko Oya View author publications You can also search for this

author inPubMed Google Scholar * Satoshi Yamamoto View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS N.S. led the project and conducted data

reduction. T.H. contributed data analysis and interpretation from the theoretical point of view. Y.Z., A.H. and S.O. contributed to data analysis and simulations. All the authors discussed

the results and commented on the manuscript. CORRESPONDING AUTHOR Correspondence to Nami Sakai. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. ADDITIONAL

INFORMATION PUBLISHER’S NOTE: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. EXTENDED DATA FIGURES AND TABLES

EXTENDED DATA FIG. 1 ASYMMETRY OF THE DISK. A, B, Degree of asymmetry with respect to 180° rotation around the disk centre (‘Point symmetry’; A) and that with respect to reflection in the

plane perpendicular to the disk mid-plane (‘Reflection symmetry’; B). The colour (see scale at right) denotes [_I_(_x_,_y_) − _I_(−_x_,−_y_)]/_I_(_x_,_y_) and [_I_(_x_,_y_) − 

_I_(_x_,−_y_)]/_I_(_x_,_y_) in A and B, respectively, where _I_(_x_,_y_) denotes the intensity at position (_x_,_y_). Here the Cartesian coordinates _x_ and _y_ are set along the disk minor

and major axes, respectively. EXTENDED DATA FIG. 2 TESTING POSSIBLE CONTRIBUTIONS OF ARTEFACTS TO THE OBSERVED PEAK OFFSET. A, B, The disk model with warp (A) and without warp (B). The

intensity scale is arbitrary. The _n_th contour represents 50 × 2_n_% (_n_ = −5, −4, −3, −2, −1, 0). C, D, Results of pseudo-observations of the disk models with warp (C) and without warp

(D) using the same _u_,_v_-pattern as in the actual observation; the images are obtained by tapering the _u_,_v_ data to give a round-shaped beam. The _n_th contour represents 20 × 2_n__σ_

(_n_ = 0, 1, …), where 1_σ_ means 0.12 mJy per beam. E, F, Pseudo-observations of the disk models with warp (E) and without warp (F) by using the same _u_,_v_-pattern in the actual

observation. The _n_th contour represents 20 × 2_n__σ_ (_n_ = 0, 1, …), where 1_σ_ means 0.09 mJy per beam. In C–F, the total flux within the 20_σ_ contour is scaled to the flux within the

same region of the observed 0.9-mm dust continuum emission. See Methods section ‘Effect of the limited distribution of the _u_,_v_ data’ for further details. EXTENDED DATA FIG. 3 TESTING

POSSIBLE CONTRIBUTIONS OF ARTEFACTS TO THE OBSERVED PEAK OFFSET AND TO THE ORBITAL PLANE ANGLE. A, Intensity peak offset (top graph) and orbital plane angle (bottom graph) at each radial

distance derived from the observed 0.9-mm image (filled circles) and that derived from the model (solid lines) using the original synthesized beam. B, As A but with the original beam and the

tapered round-beam to show the effect of beam elongation. C, Intensity peak offset and orbital plane angle at each radial distance derived from the pseudo-observations of the disk model

with warp (open circles) and without warp (crosses) for the tapered round-beam case. D, As C but for the original synthesized-beam (elongated beam) case. In A–D, the grey error bars

represent 3_σ_ Gaussian fitting errors. EXTENDED DATA FIG. 4 DISK WIDTH CALCULATED FROM A GAUSSIAN FIT OF THE INTENSITY PROFILE AT EACH RADIUS. Values are shown for the 0.9-mm and 1.3-mm

observations (filled and open symbols, respectively). Grey error bars represent 3_σ_ Gaussian fitting errors. Solid and dashed crosses at lower left represent the synthesized beam sizes for

the 0.9-mm and 1.3-mm observations, respectively. EXTENDED DATA FIG. 5 CROSS-SECTIONAL VIEWS OF THE DUST CONTINUUM EMISSION. A, B, Calculated results (‘CALC’ maps) for the 0.9-mm and 1.3-mm

dust continuum emission, respectively (see Methods). The _n_th contour represents 10 × 100.25_n__σ_ (_n_ = 0, 1, ...), where 1_σ_ is 0.001 mJy per beam. EXTENDED DATA FIG. 6 DISK WIDTH

CALCULATED FROM THE CALC MAPS. Values are shown for the 0.9-mm and 1.3-mm observations (filled and open symbols, respectively). Grey error bars represent 3_σ_ Gaussian fitting errors (see 

Methods for details). EXTENDED DATA FIG. 7 PEAK INTENSITIES ALONG THE MID-PLANE. A, B, Results for the 0.9-mm and 1.3-mm dust continuum emission, respectively. These are obtained by the

Gaussian fit of the intensity profile along the line perpendicular to the averaged disk plane. The solid and dashed grey lines represent exponential approximations of the outer and inner

parts of the disk, respectively. The outer and inner parts are divided at the knee point, which is indicated by grey dashed arrows. EXTENDED DATA FIG. 8 SPIRAL ARM MODEL. A, Top view of the

spiral arm model. B, Integrated density distribution along the _y_ axis of the model. Here the inclination angle is set to be 5° (ref. 16). The intensity scale is arbitrary. The contour

level _x_ represents 10−_x_ times the peak surface density. See Methods for details. EXTENDED DATA FIG. 9 THE PEAK POSITIONS OF THE INTEGRATED DENSITY DISTRIBUTION ALONG THE _Y_ AXIS OF THE

SPIRAL MODEL AS A FUNCTION OF THE RADIAL DISTANCE. Black lines represent the result for the spiral arm model, which are compared with the observed offsets (blue and red points show results

for the north and south parts, respectively, of the disk seen in 0.9-mm dust continuum emission). RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Sakai,

N., Hanawa, T., Zhang, Y. _et al._ A warped disk around an infant protostar. _Nature_ 565, 206–208 (2019). https://doi.org/10.1038/s41586-018-0819-2 Download citation * Received: 21 November

2017 * Accepted: 18 October 2018 * Published: 31 December 2018 * Issue Date: 10 January 2019 * DOI: https://doi.org/10.1038/s41586-018-0819-2 SHARE THIS ARTICLE Anyone you share the

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