Optical forbidden emission from Herbig AeBe stars

1
Optical forbidden emission from Herbig Ae/Be stars

• Carla Gil
• PhD Student at Université Joseph Fourier (France)
  and Universidade do Porto (Portugal)
• Catherine Dougados (LAOG), Paulo Garcia (CAUP),
  Tom Ray (DIAS), Eric Thiebaut (CRAL)

Villard-de-Lans, January 10th 2006
2
Outline

• 1 Herbig Ae/Be stars.
• 2 Optical forbidden emission from Herbig Ae/Be
  stars. Integral Field Spectroscopy with OASIS.
• 3 Indirect detection of circumstellar disks and
  extended emission.
• 4 Conclusions and perspectives.

3
Herbig Ae/Be stars

• Herbig (1960).
• Intermediate mass (2-10 Msun), pre-main-sequence
  objects.
• Spectral type A or B, with emission lines.
• Infrared excess due to thermal emission of
  circumstellar dust.
• Luminosity class from III to V.

4
Optical forbidden emission from Herbig Ae/Be stars

• Observation of six Herbig Ae/Be stars with OASIS,
  multi-mode spectro-imager, at CFHT. Spectral
  resolution of 3200.
• Object Sp. Type
  OASIS configuration Integration time (min)
  Distance (pc)
• AB Aur B9e OI, SII 41
  160
• HK Ori A4ep OI 160
  460
• LkHa 198 Aep OI 60
  ...
• LkHa 233 A7e OI 240
  880
• RR Tau A3-A5e OI 90
  800
• R Mon B... OI, SII 187
  800
• Study of forbidden emission lines OI l6300,
  l6360 and SII l6716, l6731.

5
Method

• High angular resolution observations with AO, and
  integral field spectroscopy with intermediate
  spectral resolution (FWHM 2 Ang.).
• TIGER mode of the OASIS instrument an array of
  micro-lenses samples the FOV and produces an
  image that is then dispersed and imaged in the
  detector.
• Data reduction extraction of the object spectra,
  atmospheric dispersion correction, continuum
  subtraction Imaging emission lines and
  spectro-astrometry study.

6
Indirect detection of circumstellar disks and
extended emission
7
Spectro-astrometry measuring the l dependence of
the position of an object.
After the atmospheric dispersion correction and
the continuum subtraction there was no extended
emission detected in AB Aur and RR Tau in O I.
8
HK Ori
Herbig-Haro Object
O I6300 image

• HK Ori is a binary system. Leinert et al. (1997)
  determined its parameters through
  speckle-interferometry PA 41.7 /- 0.5º,
  d0.34/-0.02() et I/-0.15/-0.15.
• We recovered the spectrum of each component of
  the binary system for the first time and detected
  an Herbig-Haro object located at d3.8(),
  PA-8º from HK Ori.

9
LkHa 198
The center of the OI image is displaced 0.1
to the NE.
HST image
O I image

• A bipolar molecular outflow was observed for the
  first time by Bally and Lada (1983).
• A companion was detected in the mid-infrared by
  Lagage (1993) and later by Corcoran Ray (1995)
  which also detected a jet at a PA of 135 º.
• On the left one can see an HST image and on the
  right an OASIS image, where the image intensity
  is given by the OI 6300 line gaussian fit
  amplitude. The small box on the right upper
  corner of the HST image shows the OASIS field of
  view.

10
LkHa 233
HST image
O I line width image

• This Herbig Ae star is located at 880 pc and is
  associated with a bipolar nebula (Herbig 1960).
• Near-IR speckle interferometric measurements
  revealed a 1000 AU halo around the central
  source.
• We have detected extended emission through
  spectro-astrometry, and were able to image the
  jet (O I 6300 line gaussian fits) in agreement
  with Corcoran Ray (1998) original detection.

11
R Monocerotis
O I image
S II image

• R Mon is the prototype Herbig Ae/Be jet driving
  star. Is is a binary system with a separation of
  0.69 located at a distance of 760 pc. R Mon
  drives a powerful jet (Brugel et al. 1984) which
  is twisted/wiggled (Movsessian et al. 2002).
• Our data traces the twisted outflow to smaller
  scales and shows the presence of a second
  redshifted outflow (Gil et al. in preparation).

12
R Monocerotis
S IIl6731 Line velocity map
Each velocity channel is 43 km/s wide.
Two microjets are observed a blueshifted N-S and
a redshifted SE-NW
(Gil et al. in preparation)
13
Conclusions

• No extended emission detected in AB Aur and RR
  Tau in OI.
• For LkHa 198 and LkHa 233, the center of the O
  I image is displaced of about 0.1 to the NE.
• HK Ori detection of an Herbig-Haro object
  slightly redshifted and propagating in the plane
  of the sky. Extraction of the spectrum of each of
  the binary components.
• R Mon detection of a second redshifted outflow.
• Nature of unresolved O I the fact that the
  center of the OI images is displaced can be due
  to the presence of a disk absorbing the light.
  Our results agree with Acke et al. (2005), which
  interpret the low velocity O I 6300 line
  profiles as arising in the surface layers of the
  disks surrounding Herbig Ae/Be stars.

14
Perspectives

• 1. R Mon observations origin of jets in Herbig
  stars
• NACO
• Obtained in service mode.
• Look for companions - S13 camera. Filtre
  Ks, narrow band filtres NB 1.64 (FeII1.6
  microns) and NB filtre, 1.75 microns.
• MIDI
• Data recently obtained.
• Determination of the 2 dimension morphology
  of the R Mon central 250 mas region.
• 3 uv-points with UT2-UT4 baseline and 2
  uv-points in each of the 2 baselines UT2-UT3 and
  UT1-UT3.
• 2. 51 Oph observations is this a new b-Pic like
  disk?
• AMBER proposal P77 approved.
• 3. Probing the 2D complex structure SINFONI?

15

• Thank you for your attention!