Re: [Utah-astronomy] McNeil's Nebula
Here's what Jay McNeil said: "Secondly--Yes, on the far-red/nir plate scans one can see a very faint stellar counterpart to IRAS 05436-0007. As a matter of fact, this object is very bright on the older 2MASS images. Furthermore, HH 22 (which happens to lie in the exact same direction as part of the new nebula)also shows as a small nebulous "blob" on deep images taken of the area with infrared sensitive equipment. HH22 is actually _just_ visible on the downloadable red scans even. The fact that the young "stellar" object presently undergoing eruption has existed and been known about for some time is not a matter of argument--the fact that it (and the resulting nebula) went from being all but invisible in the optical range to one of the more conspicuous objects in the entire field over a period of less than 3 months is what's so striking and phenomenal about the discovery! And regarding the earlier (1960's) images that distincly show the object, it has been speculated for some time now by Reipurth, Herbig, and others that such pre-main sequence eruptions are indeed periodic in nature. The fact is, however, that so "few" of these eruptions have ever been captured this early on--I had read somewhere that the going rate is one such observation every 6 to 7 years thus far. Now, let's combine that with our complete lack of knowledge regarding these speculated "periods" between such eruptions for a given young stellar object. FU Ori went form mag 16 to 10 (where it still hovers nearly 70 yrs later) in just a few months. Meanwhile, V1515 Cyg took several decades to increase by only 4 mags. The rise and fall times of such eruptions thus far recorded vary dramatically, just as the periods between subsequent eruptions are specualted to vary as well. So, in essence, it would actually make sense if this star underwent a similar eruption some other time within the past century. If this is proven so, then I personally don't see that as being any sort of "negative" aspect to my finding--just a very staggering achievement in the calculation of such outbursts.<g> Jay"
participants (1)
-
UTAHDEB@aol.com