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Saturday, February 14, 2004

Nebulous Knowledge

Well, this is annoying---er, I mean---cool. This is really cool:

Julian W. McNeil II, an amateur astronomer from Paducah, Kentucky, reports the appearance of a new cometary reflection nebula 1.1 arcminutes in diameter in the Lynds 1630 cloud in Orion. The nebula was found on several images taken on 2004 Jan 23 UT with a 7.6-cm Takahashi refractor + CCD, and it is not present on seven sky survey images from [several sky surveys] taken between 1951 and 1991. Coordinates for the new optical nebula are: R.A. = 5h 46m 14s, Dec = -00d 05.8' (J2000). McNeil's Nebula is apparently associated with IRAS 05436-0007, which consequently may have erupted.

(Sorry, the source is classified.)

Get that---McNeil's Nebula. An amateur astronomer gets a nebula named after him, in a very well-studied part of the sky. Ordinarily you have to be a guy like, well, Lynds, who did a big survey of dark clouds way back in the Paleozoic. (1962, actually, and Beverly Lynds was a woman, and so not technically a guy.)

McNeil has a labelled picture of his nebula here. It only looks tiny---that's a big field. Note the two stars apparently close together to the left of the new nebula.

Here's a pretty color picture of a much larger field which contains the nebula. It's hard to find, not least because the picture is rotated 90 degrees (er, I guess) clockwise from the other. You see the big blue-white blob of M78. Just above it is a chain of blobs, which sort of terminates in a yellow star. The very faint blob just to the left of the yellow star is the HH object labelled in the B&W phot, and the next blob as you go to the left (and down a little) is McNeil's Nebula, with the two stars beneath it (looking like one star here).

One of the sky surveys mentioned in the secret source is here (assuming that works). (This is POSS I R, for those of you playing along at home.) M78 is off the top of the field. The yellow star mentioned above is at the bottom, and the thing that looks like a crossbow is the Herbig-Haro object. If you follow the axis of the HH object, you run into those two little stars again, but you don't see McNeil's Nebula. This picture was taken in the 1950's---a long time ago, but astronomical objects don't usually change greatly in a timescale like that.

The secret source goes on to say that professional astronomers have confirmed this discovery, including the fact that it's visible in the infrared. Well, let's see if an infrared survey caught it. I checked the 2MASS database, but couldn't get a static URL for my results. I couldn't see McNeil's Nebula in any of the wavelengths (1.2, 1.6, and 2.2 microns), though it could have been there a little at the longest wavelength. You can also see the field in their color composite of the M78 field here (WARNING! 4.5M image!). M78 is in the middle of the field; McNeil's Nebula should be in the lower right. The fuzzy blue blob is the star beneath the Herbig-Haro object, which is the yellowish patch above the blue blob. Above and a little to the left of the HH object you can see the two stars I mentioned above, and to the right of them (and down) a yellow star. That's the star that accompanies McNeil's Nebula. You can maybe sort of see the beginnings of a whispy patch which may be the nebula itself.

So apparently the nebula (or rather, its exciting star) has brightened since this image was taken (probably in 1998, that's when the individual wavelength images---that I couldn't link to---were taken).

Note that the patch of red and yellow blobs below the fuzzy blue blob does not appear in McNeil's image. That's because his is an optical image (that is, usingvisible light), and that object is so obscured by dust that visible light can't get out. The very bright star to the right of the red and yellow blobs appears in McNeil's image, but it's (comparatively) much fainter in visible light.

Anyhow, congrats to McNeil for a really cool discovery. And to think, some people go to the trouble of getting PhDs and never get an object named after them.