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Title: ALMA observations of a misaligned binary protoplanetary disk system in Orion

Abstract

We present Atacama Large Millimeter/Submillimeter Array (ALMA) observations of a wide binary system in Orion, with projected separation 440 AU, in which we detect submillimeter emission from the protoplanetary disks around each star. Both disks appear moderately massive and have strong line emission in CO 3-2, HCO{sup +} 4-3, and HCN 3-2. In addition, CS 7-6 is detected in one disk. The line-to-continuum ratios are similar for the two disks in each of the lines. From the resolved velocity gradients across each disk, we constrain the masses of the central stars, and show consistency with optical-infrared spectroscopy, both indicative of a high mass ratio ∼9. The small difference between the systemic velocities indicates that the binary orbital plane is close to face-on. The angle between the projected disk rotation axes is very high, ∼72°, showing that the system did not form from a single massive disk or a rigidly rotating cloud core. This finding, which adds to related evidence from disk geometries in other systems, protostellar outflows, stellar rotation, and similar recent ALMA results, demonstrates that turbulence or dynamical interactions act on small scales well below that of molecular cores during the early stages of star formation.

Authors:
 [1]; ; ; ;  [2]; ;  [3];  [4];  [5]
  1. Institute for Astronomy, University of Hawaii, Honolulu, HI 96816 (United States)
  2. NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada)
  3. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  4. Van Vleck Observatory, Astronomy Department, Wesleyan University, 96 Foss Hill Drive, Middletown, CT 06459 (United States)
  5. CASA, University of Colorado, CB 389, Boulder, CO 80309 (United States)
Publication Date:
OSTI Identifier:
22370135
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 796; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTROSCOPY; CARBON MONOXIDE; EMISSION; HYDROCYANIC ACID; INFRARED SPECTRA; MASS; PROTOPLANETS; ROTATION; STARS; TURBULENCE; VELOCITY

Citation Formats

Williams, Jonathan P., Mann, Rita K., Francesco, James Di, Johnstone, Doug, Matthews, Brenda, Andrews, Sean M., Ricci, Luca, Hughes, A. Meredith, and Bally, John, E-mail: jpw@ifa.hawaii.edu. ALMA observations of a misaligned binary protoplanetary disk system in Orion. United States: N. p., 2014. Web. doi:10.1088/0004-637X/796/2/120.
Williams, Jonathan P., Mann, Rita K., Francesco, James Di, Johnstone, Doug, Matthews, Brenda, Andrews, Sean M., Ricci, Luca, Hughes, A. Meredith, & Bally, John, E-mail: jpw@ifa.hawaii.edu. ALMA observations of a misaligned binary protoplanetary disk system in Orion. United States. doi:10.1088/0004-637X/796/2/120.
Williams, Jonathan P., Mann, Rita K., Francesco, James Di, Johnstone, Doug, Matthews, Brenda, Andrews, Sean M., Ricci, Luca, Hughes, A. Meredith, and Bally, John, E-mail: jpw@ifa.hawaii.edu. Mon . "ALMA observations of a misaligned binary protoplanetary disk system in Orion". United States. doi:10.1088/0004-637X/796/2/120.
@article{osti_22370135,
title = {ALMA observations of a misaligned binary protoplanetary disk system in Orion},
author = {Williams, Jonathan P. and Mann, Rita K. and Francesco, James Di and Johnstone, Doug and Matthews, Brenda and Andrews, Sean M. and Ricci, Luca and Hughes, A. Meredith and Bally, John, E-mail: jpw@ifa.hawaii.edu},
abstractNote = {We present Atacama Large Millimeter/Submillimeter Array (ALMA) observations of a wide binary system in Orion, with projected separation 440 AU, in which we detect submillimeter emission from the protoplanetary disks around each star. Both disks appear moderately massive and have strong line emission in CO 3-2, HCO{sup +} 4-3, and HCN 3-2. In addition, CS 7-6 is detected in one disk. The line-to-continuum ratios are similar for the two disks in each of the lines. From the resolved velocity gradients across each disk, we constrain the masses of the central stars, and show consistency with optical-infrared spectroscopy, both indicative of a high mass ratio ∼9. The small difference between the systemic velocities indicates that the binary orbital plane is close to face-on. The angle between the projected disk rotation axes is very high, ∼72°, showing that the system did not form from a single massive disk or a rigidly rotating cloud core. This finding, which adds to related evidence from disk geometries in other systems, protostellar outflows, stellar rotation, and similar recent ALMA results, demonstrates that turbulence or dynamical interactions act on small scales well below that of molecular cores during the early stages of star formation.},
doi = {10.1088/0004-637X/796/2/120},
journal = {Astrophysical Journal},
number = 2,
volume = 796,
place = {United States},
year = {Mon Dec 01 00:00:00 EST 2014},
month = {Mon Dec 01 00:00:00 EST 2014}
}
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