Molecular Jets and H2O Masers in AFGL 5142
by
T.R. Hunter (1), L. Testi (2,3), Q. Zhang (1), T.K. Sridharan (1,4)
(1) Harvard-Smithsonian Center for Astrophysics, MS-78,
60 Garden St., Cambridge, MA 02138, USA
(2) Division of Mathematics, Physics and Astronomy, MS105-24,
California Institute of Technology, Pasadena, CA 91125, USA
(3) Present address: Osservatorio Astrofisico di Arcetri,
Largo Enrico Fermi 5, I-50125 Firenze, Italy
(4) On leave from: Raman Research Institute, Bangalore, India
Abstract:
We present centimeter and millimeter interferometric continuum and
molecular line images of the massive star-forming region AFGL 5142. A
compact (2.5 arcsec)
millimeter continuum core with integrated flux density of 125 mJy has
been detected at 88 GHz. The emission peak coincides with a
1.5 mJy centimeter continuum source. A massive (~35 Msun)
highly-collimated north-south outflow emanating from the core is seen
in both the HCO+ (1--0) and SiO (v=0,J=2--1) transitions. The
millimeter continuum source coincides with a molecular core traced by
the ambient velocity HCO+ (1--0), SiO (v=0,J=2--1), and
H13CO+ (1--0) emission. CH3CN (14-13) and (12-11) spectra
indicate a gas temperature ~65 K in the innermost core.
While the millimeter continuum
emission is probably mostly due to optically thin thermal emission
from dust grains, the centimeter continuum source is consistent with
an ionized wind. From the Lyman continuum flux required to sustain the
ionized gas, we estimate that the exciting source should be a B2 or
earlier ZAMS star.
The 22 GHz H2O masers most closely associated with the central
object have undergone substantial variability in flux and position
during three epochs spread over eight years. In addition, two new
water maser features have been detected significantly offset
(3-4", 0.03 pc) from the centimeter continuum peak position. One of
these maser features exhibits a linear structure of spots with
spatial-kinematic evidence for a rotating circumstellar disk of radius
40 A.U., and dynamical mass of ~1 Msun. The other is
found to be associated with a near infrared source with large infrared
excess. In addition to the 28 embedded stars previously seen in
infrared images, we conclude that this cluster is concurrently forming
both low and high mass stars.
Mantained by:
Leonardo Testi