73P

Images of Comet 73P-C

Mosaic of Fragement C images from May 11, 12, 15, 17.

2006 May 06

We did CW on Fragment C.

2006 May 07

We did CW and 4-us / 0.2 us imaging on Fragment C.

2006 May 11

We did CW, 4-us ranging, and the 0.1 us imaging of fragment C. Here are two images, each a sum of 14 run. It's a slow rotator.

Image of Comet 73P-C

2006 May 12

Fragment B

Today, Fragment B was in the beam for about 10 minutes. We got a quick CW at Arecibo and quite a while at Goldstone

Fragment C

9 runs of CW, then 0.1 us imaging of fragment C.

Image of Comet 73P-C

finished with a 4 minute OH hexmap

OH hexmap of Comet 73P-C

And CW spectra at Goldstone

2006 May 13

Fragment B

CW to update the ephemeris, then 4-us ranging (1-k and 8-k codes). Tried to switch to imaging, but messed up, and got a lot more 4-us imaging.

Fragment C

7 run CW, then 9 more imaging. We had a transmitter failure, so we did one OH hexmap in the middle

OH hexmap of Comet 73P-C

2006 May 14

This day was the main overlap day with Goldstone. We just did CW to get nice spectra for the comparison.

Fragment B

The spectra. The nucleus is the spike in the center and the coma is the broad skirt at the bottom. These have been separately plotted below. The Goldstone spectrum is 96 minutes integration. The Arecibo spectrum is 32 minutes integration.

The Arecibo and Goldstone spectra, coma removed. The Goldstone spectra have been scaled to the Arecibo frequency. Both seem to have some coma echo (at ~5 Hz in the Arecibo data).

After removing the nucleus, the coma-only spectrum shows S-band cross sections: sigmaOC = 0.2601577938, sigmaSC = 0.0230137222 km^2. The OC errors are entirely dominated by systematic effects. The SC echo appears to actually end at about -40 and 160 Hz, rather than just fading into the noise. The pol ratio spectrum (below) has a clear shape.

Plot of the coma
      polarization ratio

Fragment C

The Goldstone spectra (screen grab of online monitor)

2006 May 15

CW and 0.1 us imaging of B and C. Tried CW on G, but nothing obvious.

Image of Comet 73P-B

Sum of 26 runs on fragment B. Range increases down.

Image of Comet 73P-C

Sum of 16 runs on fragment C.

2006 May 16

We did 25 long code runs on Fragment B.

Image of the coma of fragment B. Range resolution is 200 us, frequency resolution is 10 Hz. Range increases up in this image.

A problem with the transmitter resulted in a double OH hexmap - inner ring at 4.1 arcmin, outer ring at 8.2 arcmin spacing

Double Hexmap of Comet 73P-B

2006 May 17

We did 15 runs of CW on fragment B and 11 on C.

Image of Comet 73P-C

Sum of 13 runs on fragment C using 0.2 us baud but 0.05 us sampling.

Image of Comet 73P-B

We took images of fragment B as well, but used a poor ephemeris. The shifted and summed image is interesting. The Doppler processing has been zero-filled to make it appear as wide as possible. It is much narrower than it was on the 15th.

2006 May 18

Another double OH hexmap - inner ring at 8.2 arcmin, outer ring at 16.4 arcmin spacing

Bigger Double Hexmap of Comet 73P-B

A double OH hexmap also of C - outer ring at 8.2 arcmin, inner ring at 4.1 arcmin spacing

Double Hexmap of Comet 73P-C

2006 May 19

OH only today, both at Arecibo and GBT. Data reduction in progress.

2006 May 20

Radar plus OH both at Arecibo and GBT. 4.1 arcmin hexmap of fragment B shown below.

Hexmap of Comet 73P-B

CW on B, CW and 0.2 imaging on C.

2006 May 21

Fragment B

CW and 0.2 imaging on B, CW on C.

And CW spectra at Goldstone

Fragment C

And CW spectra at Goldstone


Mike Nolan
Last modified: Tue Mar 27 15:33:44 AST 2007