APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

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Expand view Topic review: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Beyond » Mon Sep 09, 2013 12:08 pm

what a clever observations.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by starobin » Mon Sep 09, 2013 10:22 am

Have we become so jaded that we lost interest in all of the links imbedded in our beloved editor's comments? For instance, 'curious observers' in today's APOD. It's the cat's meow.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by geckzilla » Fri Sep 06, 2013 2:39 pm

Chris Peterson wrote: I'd call that weak evidence for the location of other stars.

It is extremely difficult in most cases to determine where stars are actually located in a single optical image. Those stars may be inside the dust, or they may be in front of it or behind it. Spectroscopy might be able to answer that question, but I don't think this image alone can.
I was looking at it the other day after reading the posts in this thread. The red channel for the image uses the F814W filter which should see through some of the dust but it's still pretty hard to tell what is going on. To me it looks like the brightest clump in the lower left might be the protostar while the two lesser ones up and to the right of it just reflecting the light from the protostar. The do like three separate areas of coalescence, though.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Chris Peterson » Fri Sep 06, 2013 1:27 pm

FLPhotoCatcher wrote:
Chris Peterson wrote:
FLPhotoCatcher wrote:There is at least one (maybe three or four) stars inside the right side of the cloud.
How are you determining that?
Clicking on the link "above image" in the description, brings up a write-up that includes this: "Spectroscopic observations of the central star within IRAS 20324+4057..." And just looking at it, the dust in the 'head' of the cloud appears to be lit up in three places.
I'd call that weak evidence for the location of other stars.

It is extremely difficult in most cases to determine where stars are actually located in a single optical image. Those stars may be inside the dust, or they may be in front of it or behind it. Spectroscopy might be able to answer that question, but I don't think this image alone can.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by geckzilla » Fri Sep 06, 2013 10:48 am

FLPhotoCatcher wrote:
Chris Peterson wrote:
FLPhotoCatcher wrote:There is at least one (maybe three or four) stars inside the right side of the cloud.
How are you determining that?
Clicking on the link "above image" in the description, brings up a write-up that includes this: "Spectroscopic observations of the central star within IRAS 20324+4057..." And just looking at it, the dust in the 'head' of the cloud appears to be lit up in three places.
Which could be caused by a single source of illumination, no?

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by FLPhotoCatcher » Fri Sep 06, 2013 5:50 am

Chris Peterson wrote:
FLPhotoCatcher wrote:There is at least one (maybe three or four) stars inside the right side of the cloud.
How are you determining that?
Clicking on the link "above image" in the description, brings up a write-up that includes this: "Spectroscopic observations of the central star within IRAS 20324+4057..." And just looking at it, the dust in the 'head' of the cloud appears to be lit up in three places.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by geckzilla » Thu Sep 05, 2013 3:12 pm

nstahl wrote:It's now Sept 5 and today's APOD isn't up. I hope everyone's ok.
Everything is indeed fine.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by nstahl » Thu Sep 05, 2013 11:36 am

It's now Sept 5 and today's APOD isn't up. I hope everyone's ok.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Glennh » Thu Sep 05, 2013 1:48 am

I'm not a trekkie but is not this, the "Dooms Day Machine" from the original Star Trek Series? :D

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by orin stepanek » Wed Sep 04, 2013 6:14 pm

:D :D :wink:
Click to play embedded YouTube video.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by geckzilla » Wed Sep 04, 2013 5:27 pm

Chris Peterson wrote:
geckzilla wrote:I run into unavailable data almost every time I search that's more than a year old.
Probably just missed. Anything that is NASA funded is in the public domain after the embargo. There may be slightly different rules where ESA is involved.
Looking at it closer, I realize that what I thought was proprietary isn't proprietary. But I'm still blocked from downloading it in the same way as the proprietary data. I don't understand why. This has frustrated me for a long time and I haven't found out who to ask about it. Equally frustrating is the lack of preview image. I'm not sure I would even want the data but I can't tell for sure because there's no preview.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Chris Peterson » Wed Sep 04, 2013 5:19 pm

geckzilla wrote:I run into unavailable data almost every time I search that's more than a year old.
Probably just missed. Anything that is NASA funded is in the public domain after the embargo. There may be slightly different rules where ESA is involved.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by geckzilla » Wed Sep 04, 2013 4:44 pm

Chris Peterson wrote:There shouldn't be anything older than a year. The initiator of an HST image can normally request a publishing embargo for up to a year to allow time to prepare a paper, but after that period the data becomes public.

It is unlikely that today's image wasn't previously available, it was simply lost in all the other data.
I run into unavailable data almost every time I search that's more than a year old. I just found a tantalizing set for NGC 7008 a few moments ago from 2009. It's UVIS so it is probably blobby and not suitable for aesthetic purposes but the available WFPC2 data cuts off the usual half of the object with its familiar stealth bomber shape and makes me wonder how the whole thing looks. Anyway, the details aren't important, but it is very common for me to run into them. Maybe it is possible to access the data through DADS but I've never tried it because it doesn't look like something I should be touching.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Chris Peterson » Wed Sep 04, 2013 4:34 pm

geckzilla wrote:Oh yeah, the "proprietary data" that litters the HLA which I'm not allowed to use but can't seem to exclude it from the results. There's a radio selection button for excluding it but it is flaky.
There shouldn't be anything older than a year. The initiator of an HST image can normally request a publishing embargo for up to a year to allow time to prepare a paper, but after that period the data becomes public.

It is unlikely that today's image wasn't previously available, it was simply lost in all the other data.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Psnarf » Wed Sep 04, 2013 4:21 pm

The Hubble site encourages folks to dig through the huge number of images to find interesting images. There aren't enough astronomers to even scratch the surface of the gazzillion images. The famous astronomer from the University of Arizona whose images frequenty grace the APOD site does just that. Except when he finds an interesting image in the Hubble database, he can add visual data from the telescopes to which he has access on Mount Lemmon (north of Tucson). He hosts public access to one of the telescopes on a regular basis so folks can explore and take images between oh-dark-thirty to midnight. (After midnight, that telescope is tasked with hunting for them pesky asteroids that ruin things for everyone.)
Sky Nights - http://skycenter.arizona.edu/

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by LocalColor » Wed Sep 04, 2013 4:20 pm

Stunning image - looks like a tadpole to us.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by geckzilla » Wed Sep 04, 2013 3:41 pm

starsurfer wrote:
FLPhotoCatcher wrote:Also, why was this image released seven years after it was taken, and not sooner?
Sometimes there can only be a public image release after the scientific study/paper has been published. The results of the study of this "tadpole" were published earlier last year: http://arxiv.org/abs/1201.2404

Sometimes an image can be published well before the results of the study have been published. An example is this Gemini image of the planetary nebula Sh2-71: http://www.gemini.edu/node/11815
Oh yeah, the "proprietary data" that litters the HLA which I'm not allowed to use but can't seem to exclude it from the results. There's a radio selection button for excluding it but it is flaky.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by starsurfer » Wed Sep 04, 2013 3:38 pm

FLPhotoCatcher wrote:Also, why was this image released seven years after it was taken, and not sooner?
Sometimes there can only be a public image release after the scientific study/paper has been published. The results of the study of this "tadpole" were published earlier last year: http://arxiv.org/abs/1201.2404

Sometimes an image can be published well before the results of the study have been published. An example is this Gemini image of the planetary nebula Sh2-71: http://www.gemini.edu/node/11815

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Chris Peterson » Wed Sep 04, 2013 3:17 pm

Ron-Astro Pharmacist wrote:Yesterdays APOD had a variety of beautifully colored stars very prominent in the photo. I'm curious why their diffraction spikes were eight as opposed to today's stars four?
Today's image was made with the HST, which has a circular aperture obstructed by a secondary mirror supported by four vanes, which create the four diffraction spikes we see. Yesterdays image was made by an unobstructed aperture that wasn't circular, but had eight sides (determined by the type of iris in the camera lens). Thus the eight diffraction spikes.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by geckzilla » Wed Sep 04, 2013 3:16 pm

Ron-Astro Pharmacist wrote:As interesting as today's APOD is, and if there are seven more years of pictures yet to be released, we've got many treats ahead. Yesterdays APOD had a variety of beautifully colored stars very prominent in the photo. I'm curious why their diffraction spikes were eight as opposed to today's stars four? :?:
Today's image is from Hubble which always has four. Scott used a telephoto Canon lens which produces eight spikes. Different instruments, different diffraction spikes. (I like that alliteration.) Those things can be very annoying if you are photographing a bright star. They get huge and ugly rather than small and pleasing.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Ron-Astro Pharmacist » Wed Sep 04, 2013 2:42 pm

As interesting as today's APOD is, and if there are seven more years of pictures yet to be released, we've got many treats ahead. Yesterdays APOD had a variety of beautifully colored stars very prominent in the photo. I'm curious why their diffraction spikes were eight as opposed to today's stars four? :?:

It made the picture yesterday quite striking.

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by BMAONE23 » Wed Sep 04, 2013 1:58 pm

Looks to me like a Cosmic Mud Puppy

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Chris Peterson » Wed Sep 04, 2013 1:50 pm

FLPhotoCatcher wrote:There is at least one (maybe three or four) stars inside the right side of the cloud.
How are you determining that?

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by Beyond » Wed Sep 04, 2013 1:47 pm

BDanielMayfield wrote: So it’s the gang of 65 O and 500 B stars in the neighbourhood off camera to the right that are emitting the radiation that’s blowing the gas and dust away from this nebula. I found the fact that there are 65 O stars in its vicinity to be amazing, since main sequence O stars are so rare. Wikipedia says that O stars make up only 0.00003 % of all stars, which is good because they are all destined to go supernova at some point. I’m also glad that this object and more importantly the rowdy gang of 65 are 4,500 light years away!
65 destined Super Novas in the same area :?: Geeze :!: When they're ready, one will probably set all the others off and create one Big Supreme Nova, that will light up our night sky :!:

Re: APOD: IRAS 20324: Evaporating Protostar (2013 Sep 04)

by BDanielMayfield » Wed Sep 04, 2013 1:08 pm

That link bystander provided is fascinating too. From it I copy this:
This light-year-long knot of interstellar gas and dust resembles a caterpillar on its way to a feast. But the meat of the story is not only what this cosmic caterpillar eats for lunch, but also what's eating it. Harsh winds from extremely bright stars are blasting ultraviolet radiation at this "wanna-be" star and sculpting the gas and dust into its long shape.

The culprits are 65 of the hottest, brightest known stars, classified as O-type stars, located 15 light-years away from the knot, towards the right edge of the image. These stars, along with 500 less bright, but still highly luminous B-type stars make up what is called the Cygnus OB2 association. Collectively, the association is thought to have a mass more than 30,000 times that of our Sun.
So it’s the gang of 65 O and 500 B stars in the neighbourhood off camera to the right that are emitting the radiation that’s blowing the gas and dust away from this nebula. I found the fact that there are 65 O stars in its vicinity to be amazing, since main sequence O stars are so rare. Wikipedia says that O stars make up only 0.00003 % of all stars, which is good because they are all destined to go supernova at some point. I’m also glad that this object and more importantly the rowdy gang of 65 are 4,500 light years away!

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