README web version of /home/usg/OPS/MTS/readme_xml/readme_76043200

Principal Investigator Email Address

• boekel@mpia.de

Estimated Total Execution Time (hours, including overheads)

• 2.0

General Description

• This small program aims to obtain a high-quality Q2-band image of
  of the HD 100453 system, using TIMMI2 at the ESO 3.6m telescope. 
  HD 100453 is one of several known Herbig Ae stars with deep minima 
  in their SED around 10 micron indicating the absence of warm (several 
  hundred K) dust. However, large amounts of cooler (<150 K) dust are 
  present. Recently, a low mass close (~100 AU) companion was discovered 
  in AO assisted images of this star. Using 2D radiative transfer models,
  we find that the SED of HD 100453 can be reproduced remarkably well with 
  a *circumbinary* disk (CBD), which would not be seen at a wavelength of 
  10 micron (where high resolution images exist) but dominates the SED at 
  20 micron. If this hypothesis is correct, the CBD should be about 4-5
  arcseconds in diameter, easily resolvable with TIMMI2. If the circumbinary 
  disk is confirmed, the companion/CBD configuration may be a general 
  explanation for the HD 100453-type SED observed in several other stars.

Waiver Requests

• No Waiver Request was submitted

Critical Observing Condition Constraints

• Since we work in Q-band, atmospheric transmission is an issue.
  As always, the less air between source and telescope the better.
  The source is comfortably far south, and is at airmass <1.3 for
  5:45 hours every day. Since the whole programm can be executed in 
  2 hours, I deemed it reasonable to ask for airmass <1.3 for these
  observations.
  
  Since good calibration of both the PSF and the photometry is
  important here, I chose the observing sequence
  calibrator - HD 100453 - calibrator - HD 100453 - calibrator.
  
  I deem that with such a setup, "clear" conditions will suffice
  to ensure well calibrated photometry.

Time-Critical Aspects

• none other than the request to execute the OBs somewhere in the 5:45 hours
  per day that the source is at airmass <1.3
  
  
  
  In my Time accounting I use:
  
  Preset+instrument setup: 5.5 min = 330s (we are continuously on the same position
  in the sky, going back and forth between calibrator and science target, 
  only 3 degrees apart).
  
  elapsed time per nod cycle: 2x120s integration time
                          0.6x2x120s chop/readout overhead
                              2x6s   nodding overhead
                          ---------- +/+
                                396s
  
  For the calibration measurements (2 nod cycles):
  330+2x396=1122 seconds per calibration
  in total 3x1092=3366 seconds.
  
  For the science measurements (4 nod cycles):
  330+4x396=1914 seconds per science measurement
  in total 2x1884=3828 seconds
  
  Adds up to 7194 seconds= 1h59m54s

Special Execution Requirements

• Please keep the following sequence of OBs (also indicated by the 
  'priority' flag). Note though that all OBs are equally important,
  and the priorities are just used to indicate the sequence of
  execution:
  
  (0. focus test, at your courtesey)
   1. calibrator OB (3 nod cycles)
   2. Science OB (9 nod cycles)
   3. calibrator OB (3 nod cycles)
   4. Science OB (9 nod cycles)
   5. calibrator OB (3 nod cycles)

Special Calibration Information

• The calibration star HD 102461 was chosen from the MIDI calibrator
  list. It is close (3 degrees) to the science target.
  
  spectral type: K5III
  V-magnitude:    5.44
  flux @ 18.75mu: 4.23 Jy
  
  With 2 nod cycles of 2x120 seconds, we get 8 minutes of
  integration time on source. With a sensitivity of 200 mJy/10sigma/hour
  (as given on TIMMI2 web site), this yields a 77 sigma detection of
  our calibrator at Q2.
  
  In order to have the best possible image quality, I would like to
  request a focus test prior to the first calibration measurement.
  Since this is not standard (and I already fill up my appointed 120
  minutes), this is at your courtesy. It would be nice if the OBs
  could be planned right after a regular focus test.

ToO Information

• N.A.

ToO Activators List

• N.A.

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• N.A.

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