This paper about 'comet-like clouds' did not happen by accident. Astronomers don't just get out of bed in the morning and say " Gee, I think I'll write a paper about comet-like clouds". In my case, however, the topic of this research just about dropped on my head out of the blue.
About a year after the Infrared Astronomical Satellite had flown, the actual data from this satellite was being distributed to the rest of the astronomical community. At the time, my collegue Lee J Rickard was working with the IRAS Team at Goddard and investigating what this satellite had to say about the inffared properties of the Zodiacal dust in our solar system. He was able to obtain a copy of the IRAS sky survey data tapes and brought them over to our office at the Naval Research Laboratory. I was instantly curious about what the entire sky looked like in the far-infrared because of my past research in the far-infrared while I was a graduate student at Harvard.
Well, there were about 250 fields to eyeball on the computer screen, each a 16 x 16 degree window onto the sky at 4 different wavelengths. I started with the 100 micron views and loaded them in one at a time. Suddenly, on field number 26, I saw a weird, isolated cloud that looked like a candelabra or the rack of a giant buck. After some thumbing through the literature we identified this as the Draco Cloud. Its shape, to me, suggested that gas and dust were being ablated by it as it traveled through the interstellar medium, and we wrote the first paper on the Draco Cloud speculating about a link between its shape and its possible rapid motion through space.
I didn't stop with Draco, but continued on with a new question. How common were Draco-like clouds in the far-infrared? Were there any other clouds seen by IRAS that showed evidence for ablation or some kind of dynamical interaction with their surroundings? I returned to the first field in the IRAS survey, but with the new question in mind to guide me, I then scrutinized all of the fields looking for more 'cometary' or 'filamentary' clouds. Eventually, I discovered 15 of them including Draco.
I then looked into the relevant physics of such encounters and tried to classify the clouds I had found into the possible dynamical categories and their morphological consequences. As a side light, I speculated that rapidly moving clouds may have star formation triggered by ram-pressure, and that this could explain star formation in the halo of the Milky Way.
So, my purely accidental discovery in the far-infrared of the Draco Cloud got me thinking about a subject in astronomy I had never explored before. Sometimes new research opportunities can come this way when you have run out of new ideas in some old line of research.