APOD: Meteor before Galaxy (2018 Aug 12)

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APOD: Meteor before Galaxy (2018 Aug 12)

Post by APOD Robot » Sun Aug 12, 2018 4:08 am

Image Meteor before Galaxy

Explanation: What's that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy in 2016, near the peak of the Perseid Meteor Shower, a sand-sized rock from deep space crossed right in front of our Milky Way Galaxy's far-distant companion. The small meteor took only a fraction of a second to pass through this 10-degree field. The meteor flared several times while braking violently upon entering Earth's atmosphere. The green color was created, at least in part, by the meteor's gas glowing as it vaporized. Although the exposure was timed to catch a Perseids meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier. Not coincidentally, the Perseid Meteor Shower peaks again tonight.

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by alter-ego » Sun Aug 12, 2018 4:37 am

APOD Robot wrote:
Sun Aug 12, 2018 4:08 am
...
Although the exposure was timed to catch a Perseids meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier.
We've been here before. The path aligns extremely well with the Kappa Cygnids (Aug 3 through Aug 25), and the travel direction would be from upper left to lower right. However I'm uncertain which way the meteor is going.
A pessimist is nothing more than an experienced optimist

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by Ann » Sun Aug 12, 2018 6:51 am

My personal sense of aesthetics makes the picture rather painful for me to look at. That shade of green! Set against the wan colors of the Andromeda galaxy! Also the green color of the meteor is quite unchanging, even though it is my understanding that meteors tend to change color from reddish, to green, to reddish again.

But I certainly don't know enough about meteors to say that the color seen in today's APOD is unlikely, let alone impossible. Lucky shot, too, when the meteor passed right in front of the galaxy - or rather, when the galaxy, the streak of the meteor and the photographer were lined up in a straight line.

Nice picture. Now I'll go and look at something that is gentler on my eyes.

Ann
Last edited by Ann on Sun Aug 12, 2018 4:23 pm, edited 1 time in total.
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heehaw

Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by heehaw » Sun Aug 12, 2018 9:21 am

Pretty!

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by heehaw » Sun Aug 12, 2018 9:25 am

My goodness! I had not yet read Ann's comment when I made my own one-word posting. Beauty is in the eye of the beholder, it has been said!

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by De58te » Sun Aug 12, 2018 9:59 am

About its direction if this was a moving video. In my opinion I would guess that the meteor is moving from the bottom to the top. The outer layer of the atmosphere is very thin of gas so the meteor entering from the lower right would hardly flare at all. Now it is entering at a certain angle and is getting lower as it moves to the top. More friction ensures more heating and the meteor does look to be getting brighter as it winds its way past the galaxy.

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by Boomer12k » Sun Aug 12, 2018 10:09 am

Really nice interesting shot. M31 is gorgeous...
Sometimes, when looking through my scopes I will see a satellite or a quick airplane...pesky humans! :lol2:


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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by neufer » Sun Aug 12, 2018 11:59 am

"I think it is time we demonstrated the full power of this station."
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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by BDanielMayfield » Sun Aug 12, 2018 2:03 pm

neufer wrote:
Sun Aug 12, 2018 11:59 am
"I think it is time we demonstrated the full power of this station."
:lol2: Deathgalaxy class, no doubt. The gap in Andromeda's ring is now explained.

Bruce
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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by BDanielMayfield » Sun Aug 12, 2018 2:59 pm

Ann wrote:
Sun Aug 12, 2018 6:51 am
My personal sense of aesthetics makes the picture rather painful to look at. That shade of green! Set against the wan colors of the Andromeda galaxy! Also the green color of the meteor is quite unchanging, even though it is my understanding that meteors tend to change color from reddish, to green, to reddish again.

But I certainly don't know enough about meteors to say that the color seen in today's APOD is unlikely, let alone impossible. Lucky shot, too, when the meteor passed right in front of the galaxy - or rather, when the galaxy, the streak of the meteor and the photographer were lined up in a straight line.

Nice picture. Now I'll go and look at something that is gentler on my eyes.

Ann
Ann loves blue, I like red, but we concur about green. Anyway, upon reading her point about the unchanging color I looked very closely at the meteor streak. Is there a slight reddening at the tail (or head)? Also I read that emission from the element nickle is green, but isn't the main reason meteors are mostly green the same reason that most auroras appear green; excited oxygen atoms?

Bruce
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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by Cousin Ricky » Sun Aug 12, 2018 3:41 pm

APOD Robot wrote:
Sun Aug 12, 2018 4:08 am
Although the exposure was timed to catch a Perseids meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier.
The first thing I noticed about the image is that the meteor does not point to the Perseus radiant.

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by Ann » Sun Aug 12, 2018 4:24 pm

BDanielMayfield wrote:
Sun Aug 12, 2018 2:03 pm
neufer wrote:
Sun Aug 12, 2018 11:59 am
"I think it is time we demonstrated the full power of this station."
:lol2: Deathgalaxy class, no doubt. The gap in Andromeda's ring is now explained.

Bruce
:lol2:

Ann
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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by zendae1 » Sun Aug 12, 2018 5:29 pm

The science behind it may be settled, and old hat, but I still marvel that something the size of a grain of sand can produce that much light.

heehaw

Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by heehaw » Sun Aug 12, 2018 7:38 pm

zendae1 wrote:
Sun Aug 12, 2018 5:29 pm
The science behind it may be settled, and old hat, but I still marvel that something the size of a grain of sand can produce that much light.
And that is not even using E = m c^2 !!!

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by Chris Peterson » Sun Aug 12, 2018 7:39 pm

zendae1 wrote:
Sun Aug 12, 2018 5:29 pm
The science behind it may be settled, and old hat, but I still marvel that something the size of a grain of sand can produce that much light.
That one was probably on the order of a centimeter. Still...
Chris

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by ta152h0 » Mon Aug 13, 2018 1:24 am

CARAMBA 1111
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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by vinkev » Mon Aug 13, 2018 9:58 pm

I note from Stellarium that the Satellite ICECUBE passed in front of the Andromeda Galaxy on the date and around the same time shown when viewed from where the astrophotographer stated on his Flickr account his image was captured. Stellarium also shows that this satellite passed by every 8 minutes 11 secs around the time of exposure, taking just a fraction of second to pass in front of Andromeda Galaxy. The trajectory is almost exactly in keeping with the ‘meteor’ on his image. My question is: could this actually be variable flare from the ICECUBE satellite rather than a passing meteor? Fantastic image though whether it was a passing satellite or a meteor.

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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by Chris Peterson » Tue Aug 14, 2018 3:47 am

vinkev wrote:
Mon Aug 13, 2018 9:58 pm
My question is: could this actually be variable flare from the ICECUBE satellite rather than a passing meteor? Fantastic image though whether it was a passing satellite or a meteor.
No. Satellite flares are generally white (the color of the Sun), or sometimes shifted a bit towards red by the way light scatters. This green is absolutely typical of a meteor, some combination of ionized atmospheric oxygen and ionized iron from the body itself.
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Re: APOD: Meteor before Galaxy (2018 Aug 12)

Post by neufer » Tue Aug 14, 2018 11:46 am

Chris Peterson wrote:
Tue Aug 14, 2018 3:47 am
vinkev wrote:
Mon Aug 13, 2018 9:58 pm

My question is: could this actually be variable flare from the ICECUBE satellite rather than a passing meteor? Fantastic image though whether it was a passing satellite or a meteor.
No. Satellite flares are generally white (the color of the Sun), or sometimes shifted a bit towards red by the way light scatters. This green is absolutely typical of a meteor, some combination of ionized atmospheric oxygen and ionized iron from the body itself.
https://www.amsmeteors.org/fireballs/faqf/#5 wrote:
American Meteor Society
Fireball FAQs

<<The dominant composition of a meteoroid can play an important part in the observed colors of a fireball, with certain elements displaying signature colors when vaporized. For example, sodium produces a bright yellow color, nickel shows as green, and magnesium as blue-white. The majority of light from a fireball radiates from a compact cloud of material immediately surrounding the meteoroid or closely trailing it. 95% of this cloud consists of atoms from the surrounding atmosphere; the balance consists of atoms of vaporized elements from the meteoroid itself. These excited particles will emit light at wavelengths characteristic for each element. The most common emission lines observed in the visual portion of the spectrum from ablated material in the fireball head originate from iron (Fe), magnesium (Mg), and sodium (Na). Silicon (Si) may be under-represented due to incomplete dissociation of SiO2 molecules. Manganese (Mn), Chromium (Cr), Copper (Cu) have been observed in fireball spectra, along with rarer elements. The refractory elements Aluminum (Al), Calcium (Ca), and Titanium (Ti) tend to be incompletely vaporized and thus also under-represented in fireball spectra.>>
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