THE TIME-EVOLUTION OF HH 2 FROM FOUR EPOCHS OF HST IMAGES
Por:
Raga, A. C., Reipurth, B., Velazquez, P. F., Esquivel, A., Bally, J.
Publicada:
1 dic 2016
Resumen:
We have analyzed four epochs of H alpha and [S II] Hubble Space
Telescope images of the HH 1/2 outflow (covering a time interval from
1994 to 2014) to determine proper motions and emission line fluxes of
the knots of HH 2. We find that our new proper motions agree
surprisingly well with the motions measured by Herbig & Jones, although
there is partial evidence for a slight deceleration of the motion of the
HH 2 knots from 1945 to 2014. We also measure the time-variability of
the H alpha intensities and the [S II]/H alpha line ratios and find
that knots H and A have the largest intensity variabilities (in 1994 ->
2014). Knot H, which now dominates the HH 2 emission, has strengthened
substantially, while keeping an approximately constant [S II]/H alpha
ratio. Knot A has dramatically faded and at the same time has had a
substantial increase in its [S II]/H alpha ratio. Possible
interpretations of these results are discussed.
Filiaciones:
Raga, A. C.:
Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, AP 70-543, Mexico City 04510, DF, Mexico
Reipurth, B.:
Univ Hawaii Manoa, Inst Astron, Hilo, HI 96720 USA
Velazquez, P. F.:
Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, AP 70-543, Mexico City 04510, DF, Mexico
Esquivel, A.:
Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, AP 70-543, Mexico City 04510, DF, Mexico
Bally, J.:
Univ Colorado, Ctr Astrophys & Space Astron, UCB 389, Boulder, CO 80309 USA
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