Diapositiva 1

1
Proper motion of thermal sources in star-forming
regions
Laurent Loinard
Centro de Radioastronomía y Astrofísica, UNAM
Morelia, Michoacán
Collaborators Luis F. Rodriguez, Laura Gomez,
Susana Lizano Claire Chandler, Crystal
Brogan Paul Ho, David Wilner
2
IRAS 16293-2422
Low luminosity (L 20 Lsun). Class 0 source (age
a few 104 yrs) First recognized protobinary system
Mizuno et al. 1990
3
Proper motions
Loinard 2002
4
Proper motions
Chandler et al. 2005
5
So
A hierarchical proto-triple system or a strongly
precessing jet?
6
Loinard et al. 2007
??
7
Pech et al., in prep
8
Pech et al., in prep
9
Jet orientation
Hirano et al. 2001
10
(No Transcript)
11
Conclusions on IRAS16293
IRAS 16293-2422 is a triple system that just
ejected a pair of gas blobs. First time such an
ejection is observed live we have witnessed
the very birth of an HH pair. It is the youngest
known triple system. Proper motions will
eventually allow the determination of the masses
of all the components Forthcoming observations
will allow us to study with unprecedented detail
the evolution of the ejecta.
12
Orion
KL flow
(NICMOS 2.12 microns Schultz et al. 2000)
ODell NASA (WFPC)
13
Orion
Red 2.12 ?m Green 2.17 ?m Blue 2.27 ?m
14
BN/KL
(Shuping et al. 2004 Wilson et al. 2000)
Gezari et al. (2000)
15
At the VLA
16
Motions
Tan (2004)
(30 km/s)
BN ejected from ?1C 4000 years ago.
17
But
Rodriguez et al. 2005
18
BN moves to the NW at 27/-1 km s-1.
I moves to the SE at 12/-2 km s-1.
19
Going back in time
The two sources were (at least in projection)
very near each other 500 yrs ago
RS I
Gezari et al. (2000)
20
Actually, three sources
Gomez et al. 2005, 2007
21
Going back in time
All three sources were (at least in projection)
very near each other 500 yrs ago
But 500 yrs is just about the age of the KL
outflow (John Bally, private communication)
RS I
And the locus of the position where the sources
were very near the origin of the flow
Gezari et al. (2000)
22
(No Transcript)
23
So how is this related to the KL object?
24
Energetics

• Kinetic energy of BNIn approx 2 x 1047 ergs
• Total energy of the KL flow approx 4 x 1047
  ergs
• Energy liberated by a 1Msun 20 Msun merger
  approx 3 x 1048 ergs

No need for a merger really. Rapid accretion of a
modest disk as a result of the dynamical
encounter would be sufficient
25
Conclusions on Orion

• There is strong evidence that BN, I and n were
  once members of a now-defunct multiple system.
• The dynamical decay of that system is very
  likely related to the existence of the KL flow.

26
Thanks to a 10-fold increase in continuum
sensitivity, the EVLA will allow such studies to
be made in dozens of young stellar sources. The
time dimension is very important to understand
early stellar evolution. The continuous
spectral coverage will allow the detection of RRL
(3D dynamics) and the determination of spectral
index, and identification of emission mechanism.