README web version of /home/usg/OPS/MTS/readme_xml/readme_81502306

Principal Investigator Email Address

• juhasz@mpia.de

Estimated Total Execution Time (hours, including overheads)

• 2.0

General Description

• This programme is aimed at obtaining a high quality N-band spectrum of
   the
  outbursting YSO EX Lupi. We wish to analyze the dust composition in the
  upper layers of the EX Lupi disk. In january this object increased by
  a factor of 100 in optical brightness, and since then has been fading as
  a general trend, though the light curve is very irregular, and shows 
  \\\"peaks and valleys\\\" with an amplitude of up to 2 mag. We are monitoring
  the star in the optical every day, weather allowing.
  
  Spectra taken before the outburst show only amorphous dust. In-outburst
  Spitzer spectroscopy shows large amounts of crystlline dust, that must have
  been produced by the outburst heat.
  
  The dust in the upper disk layers should go back to amorphous on a time-scale
  of <50 years (50 years ago, the object showed an outburst of similar magnitude
  to the current one). The observations of this DDT programme are aimed at
  monitoring the 10 micron spectrum, and measuring the transformation back to
  an amorphous appearance.
  
  The time scale on which this happens is unknown (apart from that it is <50 years),
  yet is highly interesting: it provides a direct measure of the amount of turbulence
  in the inner region of an accretion disk (this is one of the most uncertain
  quantities in modern disk models, and has never been measured).
  
  We will take spectra at 2 epochs, one ASAP as the source is now in a low state
  (OB name SCI_EXLUP_low_state), and another in case the source brightens again
  (we are monitoring the object in the optical, the Garching support astronomer 
  will \"release\" the appropriate SCI_EXLUP_high_state OB in due time).
  
  In practice, the programme comprises taking two VISIR spectra of a ~1-3 Jy source
  (the IR flux is strongly variable), and should be pretty straightforward.

Waiver Requests

• No Waiver Request was submitted

Critical Observing Condition Constraints

• Clear conditions should suffice.

Time-Critical Aspects

• The first measurements should be performed as soon as possible.
  As we write (august 20), the source is in a low state and we
  need a 10 micron spectrum in this state to zoom in on the inner
  disk (by means of tomography).
  
  For the timing of the second measurement, we will monitor the
  optical light curve, and hope that it will rise again sometime
  during the coming month (it has shown brightness variations
  of ~2 magnitudes up and down on >~1 week time scales several
  times during the fading phase of the current outburst). This
  measurement in the high state will give the most direct
  comparison to existing measurements, and serve best to constrain
  the turbulence in the disk.

Special Execution Requirements

• ---(Empty)---

Special Calibration Information

• Unfortunately, our allocated observing time leaves no time for the
  \"optimal\" calibration (long story - we originally requested and were
  granted MIDI time, but these turned out both difficult for ESO to schedule,
  as well as less suited for our purposes, new insights based on MIDI and
  VISIR measurments taken during the past months).
  
  Anyway, we have taken the liberty to send along a *suggested* calibrator,
  which perfectly matches the EX lupi airmass when observed after the
  science OB (relatively independent of the exact timing, the calibrator
  traces approximately the same airmass-time curve as EX lupi, with a ~30 min
  delay). If this calibrator would fit in with the rest of the service mode
  programme, it would be fantastic if you would manage to observe it.
  Of course we fully understand that we are in no position to make any
  claims, and that it is fully up to your courtesy whether or not it is
  feasible to tune your general calibration to our needs.
  As fate has it, the Enstatite feature we are characterizing sits on the
  flank of the Ozone featere, and thus telluric calibration is quite crucial.
  
  The calibrator is taken from the Cohen network, and we have already
  used it to calibrate previous VISIR and MIDI measurements, which worked
  out fine. Thus, there is no doubt concerning its general applicability,
  it can savely be used to calibrate observations performed under other
  programmes taken at similar airmass. Note that EX lupi's RA puts our
  observations at the very beginning of the night.

ToO Information

• ---(Empty)---

ToO Activators List

• ---(Empty)---

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• ---(Empty)---

Source(s) of Pre-imaging

• ---(Empty)---

Pre-imaging sources not listed above

• ---(Empty)---

Do all your OBs comply with the instrument-specific requirements listed
 on the instrument-specific Phase 2 web page ?

• YES

If this is a pre-imaging run, did you select PRE-IMAGING for the Observing
 Category for each Observing Template ?

• N/A

Do all your finding charts comply with both the general and instrument-specific
 Phase 2 Web Pages ?

• YES

If you submitted OBs for standard stars, did you specify the magnitude
 and spectral type of all standard stars in the OBs ?

• YES

Have you included OBs for any calibrations that you need but which are
 not part of the Calibration Plan ?

• YES

If you are observing Moving Targets, have you attached suitable ephemeris
 files to your OBs?

• N/A

If you have preferences which OBs should be executed first, did you make
 use of the User Priority field in the OBs ?

• YES

If this is a run that requires coordinated observations with other facilities,
 did you give proper instructions in the Time-Critical Aspects Section ?

• N/A

If the provided finding chart is at a different wavelength than the observations,
 did you clearly describe in the README file how to identify the target?

• N/A

Did you specify a guide star brighter than V=12mag within a field of
 r=5arcmin around the science target?

• N/A