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Proper motion of thermal sources in star-forming regions

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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 2

3 Proper motions… Loinard 2002 3

4 Proper motions… Chandler et al. 2005 4

5 A hierarchical proto-triple system or a strongly precessing jet?
So… A hierarchical proto-triple system or a strongly precessing jet? 5

6 Loinard et al. 2007 ?? 6

7 Pech et al., in prep

8 Pech et al., in prep

9 Jet orientation… Hirano et al. 2001 9

10

11 Conclusions on IRAS16293: IRAS 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)
O’Dell & 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…
Poner la referencia 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

23 So… how is this related to the KL object?

24 Kinetic energy of BN+I+’n’: approx 2 x 1047 ergs
Energetics… Kinetic energy of BN+I+’n’: 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.


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