X-ray activity and the YSO circumstellar environment: results from DROXO

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X-ray activity and the YSO circumstellar
environment results from DROXO

• Ettore Flaccomio
• B.Stelzer, S. Sciortino, I.Pillitteri, G. Micela

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Outline

• The Deep Rho Ophiuchi XMM-Newton Observation
  (DROXO)
• X-rays and the circumstellar environment
  observational proxies
• The Ne II 12.81mm fine structure line
• The Fe 6.4 keV fluorescent line
• Modeling of X-ray flares loop lengths
• Conclusions

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• DROXO
• PI. S. Sciortino
• see poster
• Pillitteri et al.
• ?Oph (core F)
• EPIC 450 Ksec
• High background
• 111 X-ray sources
• ?Oph
• age 1 Myr.
• d 120 pc

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Ne II 12.81µm fine structure line

• Stellar X-rays heat and ionize circumstellar disk
  (e.g. Igea Glassgold 1999, Glassgold et al.
  2004)
• Ne 1st and 2nd ionization potentials 21.56
  and 41.0 eV

Glassgold et al. (2007) Mejierink et al. (2008)
Gorti Hollenback (2008)
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First Ne II detections

• Lahuis et al. (2007)
• Pascucci et al. (2007)

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First Ne II detections

• Espaillat et al. (2007)

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DROXO/IRSSample

• 28 objects in the DROXO field with high
  resolution SPITZER IRS spectra
• 25 X-ray sources
• 3 upper limits

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IRS spectra
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Ne II vs. LX
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Ne II vs. accretion
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Fe 6.4keV fluorescent Ka line
Bai (1979), Drake et al. (2007)
Drake et al. (2007)
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YLW 16A (Class I)
Chandra ACIS - Imanishi et al. (2001)
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COUP
Tsujimoto et al. (2005)
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COUP (331, V1486 Ori)
Czesla Schmitt (2007)
EW680(450-920) kT gt 13 keV
EW1400
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Elias 29 (DROXO)
Giardino et al. (2007) see also Favata et al.
(2005)
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YLW 16A (Class I)
EW60 ( 6-120) kT 3.8 keV
Quiescent FX 1.2 10-12 erg s-1cm-2 Maximum
FX 30-40 10-12 erg s-1cm-2
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YLW 16A (Class I)
EW170( 70-270) kT 9.3 keV
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IRS 43 (Class I)
EW100(50-150) kT 2.4 keV
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IRS 43
EW380 (180-570) kT 2.4 keV
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Fe 6.4keV fluorescent Ka lineSummary of results

• Line associated with flares high kT and EW as
  predicted
• YWL 16A 2x, 79 in Giardino et al. (2007,
  Serpens) , (6 COUP sources?)
• Line associated with flares high kT and EW gtgt
  than predicted
• V1486 Ori
• Line not associated with flares low kT and EW
  gtgt than predicted
• Elias 29 2x, IRS 43
• Special geometries?
• Collisional ionization by high energy
  electrons within accretion tubes?
• Giardino et al. (2007, Elias 29)

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Flare Modelling
L (0.96 ?0.17) ? 1012 cm 14 R?
Reale et al. (1997, 2004)
Favata et al. (2005) 10 flares imply L gt 5 R
Favata et al. (2005)
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YLW 16A (class I)
L 3.3-3.7 R?
L 18.2 R? 0.085AU
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IRS 55 (class III)
IRS 55/GY 380 (III)
L (10.9 11.5)R? 0.05AU
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GY 262 (class II)
L (26 28)R? 0.12 AU
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GY 463 (class III)
L (3.2 4.4)R?
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Conclusions

• X-rays have a significant impact on circumstellar
  disks (and therefore on star and planet
  formation)
• X-ray data are helping us understand disks
• Disk models should include an accurate spatial,
  spectral and temporal description of the X-ray
  emission.
• We do not fully understand the Fe 6.4keV line
  emission mechanism
• Better X-ray data is needed (e.g. better
  sensitivity for Fe 6.4keV and modeling of fainter
  flares)