APOD: Long Lovejoy and Little Dumbbell (2015 Feb 27)

[APOD Robot]

Long Lovejoy and Little Dumbbell

Explanation: Buffeted by the solar wind, Comet Lovejoy's crooked ion tail stretches over 3 degrees across this telescopic field of view, recorded on February 20. The starry background includes awesome bluish star Phi Persei below, and pretty planetary nebula M76 just above Lovejoy's long tail. Also known as the Little Dumbbell Nebula, after its brighter cousin M27 the Dumbbell Nebula, M76 is only a Full Moon's width away from the comet's greenish coma. Still shining in northern hemisphere skies, this Comet Lovejoy (C/2014 Q2) is outbound from the inner solar system some 10 light-minutes or 190 million kilometers from Earth. But the Little Dumbbell actually lies 3 to 5 thousand light-years away. Now sweeping steadily north toward the constellation Cassiopeia Comet Lovejoy is fading more slowly than predicted and is still a good target for small telescopes.

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[ta152h0]

Is this comet a good target for, let's say Hubble ?

[geckzilla]

Is this comet a good target for, let's say Hubble ?

Sure. Hubble's looked at a lot of comets. But even Hubble can't quite see the nucleus of a comet. This article can give you a good idea of what Hubble might see if it were to look at the comet. http://www.nasa.gov/mission_pages/hubbl ... olmes.html

[starsurfer]

That is a really pretty and unusual pairing! The planetary nebula is a delightful bonus! Another image of the two together is this one by Pepe Chambó.

[kellogg]

I've never seen such a ragged tail on a comet before.

Is that common?

Scott Kellogg

[Tucker M]

What is the thin dark line extending nearly half way across the image, starting on the left edge and splitting one of the brighter stars as it heads diagonally upwards? A satellite trail I assume, but wondering if anyone knows for sure.

[rstevenson]

There is an odd area of blue stars around that bright blue one below the comet's nucleus. Is that just a processing artifact?

Rob

[MarkBour]

What is the thin dark line extending nearly half way across the image, starting on the left edge and splitting one of the brighter stars as it heads diagonally upwards? A satellite trail I assume, but wondering if anyone knows for sure.

Thanks for pointing that out, I would have missed it ! But now that I look more closely, it goes farther. It goes all the way to the upper right corner of the image. And there is another line that crosses it a little more than halfway up from the cometary tail to the upper right corner. (I'm not certain the upper portion is the same line/track/artifact, but I think it is). The one that crosses is almost vertical (it has a large negative slope) on the image.

[starsurfer]

There is an odd area of blue stars around that bright blue one below the comet's nucleus. Is that just a processing artifact?

Rob

I don't have access to my starchiest now but this might be the open cluster Melotte 20.

[Ann]

This is a very fine picture. I love the background sky, absolutely peppered with colorful stars. Of course we are looking at constellation Perseus, so we are in the band of the Milky Way, although not in the thickest and most luminous part of it. Regardless, this is the kind of cosmic neighborhood where we expect to see stars, not distant galaxies.

Of course we may see planetary nebulas here, too, so M76 is not a surprising but a welcome sight. I think it is so interesting to compare the colors of the Little Dumbbell and Comet Lovejoy. M76 appears to be a little more aqua-colored than Lovejoy, which is more clearly green. But the difference is small. I found a picture by David Lane where the color difference between the comet and the planetary is quite striking.

But back to today's APOD. Another feature that is striking is the bright blue star at about 5 o'clock. This is in itself a truly fascinating star, Phi Persei. It is a madly rotating hot star of spectral class B2, surrounded by a thick equatorial ring. And the B2 primary has a blisteringly hot companion, an O-type dwarf. This scorching star is probably on its way to becoming a white dwarf, and the thick equatorial ring surrounding the primary (and a matching ring surrounding the secondary) may be remnants of the outer, now cast-off atmosphere of the O-type dwarf. This super-hot midget may be in the process of creating its own planetary nebula. Who knows, our future descendants may see two planetary nebulas in the direction of the Little Dumbbell.

Although Comet Lovejoy will be lost among millions of other pieces of rock orbiting the Sun by the time we get a planetary nebula in Phi Persei.

Ann

[rstevenson]

There is an odd area of blue stars around that bright blue one below the comet's nucleus. Is that just a processing artifact?

Rob

I don't have access to my starchiest now but this might be the open cluster Melotte 20.

No, I wasn't asking about the stars, though that wasn't at all clear from my question, I belatedly see. I meant that the area around that bright star is all blueish. If I put the crosshairs of my color meter in a dark area elsewhere in the picture, it reads about 7 to 10% in each of the RGB channels. But in that area I'm asking about, even the background darkness reads about 25% blue, while the red and green remain below 10%.

So I was wondering if there was a processing decision made to enhance the blueness of that bright star, and this affected the area around it too, or if perhaps there is something between that star and us -- gas, dust -- which is glowing blue.

Rob

[Ann]

There is an odd area of blue stars around that bright blue one below the comet's nucleus. Is that just a processing artifact?

Rob

It sure looks like a processing artifact to me. To the best of my knowledge, there isn't a background (or even foreground) cluster along the line of sight to Phi Persei.

There is a blue "halo" surrounding Phi Persei, which I definitely take to be an artifact. The stars inside this halo look blue, but that is almost certainly an illusion.

Ann

[rstevenson]

Thanks Ann, for confirming I'm not imagining it. (You answered while I was re-asking.)

Rob

[Ann]

Rob wrote:
So I was wondering if there was a processing decision made to enhance the blueness of that bright star, and this affected the area around it too, or if perhaps there is something between that star and us -- gas, dust -- which is glowing blue.

My software doesn't say that there is a reflection nebula around Phi Persei.

I think we are dealing with the fact that Phi Persei is the brightest star in this picture, and that it is the most strongly colored one of the bright stars. For whatever reason, I think the color has been "bleeding" into the surroundings in this picture.

Ann

[Ron-Astro Pharmacist]

I'm sorry if I've been over posting but I'd hate to see someone miss this if they have good seeing, clear skies and a good set of binoculars. We saw it the other night quite well as it approached Cassiopeia.

http://www.skyandtelescope.com/wp-conte ... ovejoy.pdf

Unfortunately it's overcast here.

[Ron-Astro Pharmacist]

From : Submissions -
Thanks for sharing Tamas

http://www.vadakcsillaga.hu/naprend/201 ... 50317.html

The clouds departed and it was visible through binoculars still. This is a much better view though.

[ta152h0]

So Mr Peterson took his telescope elsewhere and baited clouds out of town ? Very nice image

[Roberto Capacci]

Pretty image!