Irradiated Protostellar Jets

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Irradiated Protostellar Jets

• Kai Cai
• Feb. 27, 2004

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Comparisons

• Normal HH
• Sources highly obscured
• Most of the mass invisible
• Irradiated HH
• YSO optically visible
• Intensities of emission lines determined by
  external irradiation H? ? emission measure,
• SII ? electron density

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Irradiated HH jets

• ? Orion
• Orion Nebula
• NGC 1333
• Rosette Nebula
• Morphology C-shaped symmetry about the source

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Irradiated Jet in Rosette Nebula Li Rector
(2004)

• Rosette Nebula HII region excavated by nearby O
  stars from NGC2244

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Observations (Rosette HH1)

• KPNO 0.9m MOSAIC - March, 1999
• Spectroscopy 2.16m, NAOC (Beijing)
• Jan, 2003

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H? Image of Rosette HH1
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Observational Results

• Bow shock structure on the opposite side
• possibly a degenerated counterjet
• OIII diffuse, omni-present
• vs. SII decrease rapidly from the base of the
  jet
• Energy source (YSO) a F8 Ve star
• SED fitting 2MASS data ? Mdisk 0.006M?

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Observational Results (Contd)

• Inverse P Cygni profile in H?
• ? low-density in circumstellar material

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Effects (discussed by Bally Reipurth 2001)

• Mass loss once sound speed Vescape
• The heated layer can reach T 100-1000K
• Stop further stellar growth?

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Li Rector (2004)

• Reipurth et al. (1998) External ionization
• help in feeding the jet
• Speculate relic disk mass loaded into the jet ?
  stop the accretion ? lead to a failed star (BD)/
  planemo

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Conclusions?

• UV radiation from massive stars halts the
  formation of low-mass stars and create brown
  dwarfs?

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BDs in Young Clusters

• IC 348 youngest
• Cha I
• Taurus Upper Sco 3-5Myr
• ? Orion 5Myr
• TW Hydrae Association 10Myr
• ? Oph
• IC 2391 35Myr
• Planemos ? Orion, Trapezium, Upper Sco