TY - JOUR
T1 - VLA and CARMA observations of protostars in the Cepheus clouds
T2 - Sub-arcsecond proto-binaries formed via disk fragmentation
AU - Tobin, John J.
AU - Chandler, Claire J.
AU - Wilner, David J.
AU - Looney, Leslie W.
AU - Loinard, Laurent
AU - Chiang, Hsin Fang
AU - Hartmann, Lee
AU - Calvet, Nuria
AU - D'Alessio, Paola
AU - Bourke, Tyler L.
AU - Kwon, Woojin
PY - 2013/12/20
Y1 - 2013/12/20
N2 - We present observations of three Class 0/I protostars (L1157-mm, CB230 IRS1, and L1165-SMM1) using the Karl G. Jansky Very Large Array (VLA) and observations of two (L1165-SMM1 and CB230 IRS1) with the Combined Array for Research in Millimeter-wave Astronomy (CARMA). The VLA observations were taken at wavelengths of λ = 7.3 mm, 1.4 cm, 3.3 cm, 4.0 cm, and 6.5 cm with a best resolution of 0.″06 (18 AU) at 7.3 mm. The L1165-SMM1 CARMA observations were taken at λ = 1.3 mm with a best resolution of 0.″3 (100 AU) and the CB230 IRS1 observations were taken at λ = 3.4 mm with a best resolution of 3″ (900 AU). We find that L1165-SMM1 and CB230 IRS1 have probable binary companions at separations of 0.″3 (100 AU) from detections of secondary peaks at multiple wavelengths. The position angles of these companions are nearly orthogonal to the direction of the observed bipolar outflows, consistent with the expected protostellar disk orientations. We suggest that these companions may have formed from disk fragmentation; turbulent fragmentation would not preferentially arrange the binary companions to be orthogonal to the outflow direction. For L1165-SMM1, both the 7.3 mm and 1.3 mm emission show evidence of a large (R > 100 AU) disk. For the L1165-SMM1 primary protostar and the CB230 IRS1 secondary protostar, the 7.3 mm emission is resolved into structures consistent with 20 AU radius disks. For the other protostars, including L1157-mm, the emission is unresolved, suggesting disks with radii <20 AU.
AB - We present observations of three Class 0/I protostars (L1157-mm, CB230 IRS1, and L1165-SMM1) using the Karl G. Jansky Very Large Array (VLA) and observations of two (L1165-SMM1 and CB230 IRS1) with the Combined Array for Research in Millimeter-wave Astronomy (CARMA). The VLA observations were taken at wavelengths of λ = 7.3 mm, 1.4 cm, 3.3 cm, 4.0 cm, and 6.5 cm with a best resolution of 0.″06 (18 AU) at 7.3 mm. The L1165-SMM1 CARMA observations were taken at λ = 1.3 mm with a best resolution of 0.″3 (100 AU) and the CB230 IRS1 observations were taken at λ = 3.4 mm with a best resolution of 3″ (900 AU). We find that L1165-SMM1 and CB230 IRS1 have probable binary companions at separations of 0.″3 (100 AU) from detections of secondary peaks at multiple wavelengths. The position angles of these companions are nearly orthogonal to the direction of the observed bipolar outflows, consistent with the expected protostellar disk orientations. We suggest that these companions may have formed from disk fragmentation; turbulent fragmentation would not preferentially arrange the binary companions to be orthogonal to the outflow direction. For L1165-SMM1, both the 7.3 mm and 1.3 mm emission show evidence of a large (R > 100 AU) disk. For the L1165-SMM1 primary protostar and the CB230 IRS1 secondary protostar, the 7.3 mm emission is resolved into structures consistent with 20 AU radius disks. For the other protostars, including L1157-mm, the emission is unresolved, suggesting disks with radii <20 AU.
KW - ISM: individual objects (CB230, L1165, L1157)
KW - protoplanetary disks
KW - stars: formation
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U2 - 10.1088/0004-637X/779/2/93
DO - 10.1088/0004-637X/779/2/93
M3 - Article
AN - SCOPUS:84890085261
VL - 779
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 93
ER -