APOD: M44: The Beehive Cluster (2022 Apr 30)

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APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by APOD Robot » Sat Apr 30, 2022 4:05 am

Image M44: The Beehive Cluster

Explanation: A mere 600 light-years away, M44 is one of the closest star clusters to our solar system. Also known as the Praesepe or the Beehive cluster its stars are young though, about 600 million years old compared to our Sun's 4.5 billion years. Based on similar ages and motion through space, M44 and the even closer Hyades star cluster in Taurus are thought to have been born together in the same large molecular cloud. An open cluster spanning some 15 light-years, M44 holds 1,000 stars or so and covers about 3 full moons (1.5 degrees) on the sky in the constellation Cancer. Visible to the unaided eye, M44 has been recognized since antiquity. Described as a faint cloud or celestial mist long before being included as the 44th entry in Charles Messier's 18th century catalog, the cluster was not resolved into its individual stars until telescopes were available. A popular target for modern, binocular-equipped sky gazers, the cluster's few yellowish tinted, cool, red giants are scattered through the field of its brighter hot blue main sequence stars in this telescopic group snapshot. Dramatic diffraction spikes highlighting the brighter cluster members were created with string crossed in front of the telescope's objective lens.

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by Ann » Sat Apr 30, 2022 5:14 am

M44-resized1024[1].jpg
The Beehive Cluster. Image: Drew Evans.

The very prominent star spikes make today's APOD quite beautiful, but they also make it somewhat harder to discern the defining properties of M44.

So what are the defining properties of M44?

Beehive Cluster Zeppetello somewhat annotated.png

I'd say that the Beehive Cluster lacks a strongly defining shape. There is no "dipper" of the Pleiades, no "V" of the Hyades and no "owl" of NGC 457.

But what the Beehive lacks in defining shape, it makes up for in stellar groupings and contrasting colors. Many of the brightest stars of the Beehive are found in visible pairs or triplets. And in all three prominent triplets, one of the members is an orange giant, whereas the others are bluish A-type stars (or in some cases, perhaps whitish F-type stars - I still don't have my software).

So that's the Beehive cluster for me! :D

Ann
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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by DrewJEvans » Sat Apr 30, 2022 5:40 am

Thanks so much for selecting my image as APOD.

Quite honored. Clear skies everyone. ✨

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by AVAO » Sat Apr 30, 2022 8:03 am

APOD Robot wrote: Sat Apr 30, 2022 4:05 am ...., the cluster was not resolved into its individual stars until telescopes were available.
JWST thinks that stars are burning :-)

Image
https://blogs.nasa.gov/webb/2022/04/28/ ... issioning/
Credit: NASA/STScI

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by orin stepanek » Sat Apr 30, 2022 1:34 pm

M44-resized1024.jpg
Oh so pretty is the Beehive Cluster!🤩
Hyades_Mtanous_1998.jpg
The Hyades pretty neat also thought to come from same molecular
cloud as the Beehive! 8-)
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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by XgeoX » Sat Apr 30, 2022 3:08 pm

DrewJEvans wrote: Sat Apr 30, 2022 5:40 am Thanks so much for selecting my image as APOD.

Quite honored. Clear skies everyone. ✨
A very worthy image indeed Drew! It’s so beautiful and sharp my first thought was “Hubble”. :D
Thanks for sharing!


Eric
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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by Leon1949Green » Sat Apr 30, 2022 4:01 pm

What diameter string did you use?

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by Chris Peterson » Sat Apr 30, 2022 4:03 pm

APOD Robot wrote: Sat Apr 30, 2022 4:05 am Dramatic diffraction spikes highlighting the brighter cluster members were created with string crossed in front of the telescope's objective lens.
I wish there was a magic string I could put in front of my telescope to remove diffraction spikes!
Chris

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by FrankTKO » Sat Apr 30, 2022 4:15 pm

Hmmm, so you can have red giants that are young? I though these stars were much older...

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by Chris Peterson » Sat Apr 30, 2022 5:01 pm

FrankTKO wrote: Sat Apr 30, 2022 4:15 pm Hmmm, so you can have red giants that are young? I though these stars were much older...
Stars up to about 8 solar masses pass through a red giant phase, and at 8 solar masses that occurs at less than 50 million years of age.
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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by FrankTKO » Sat Apr 30, 2022 9:13 pm

Thank you !

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by johnnydeep » Sat Apr 30, 2022 9:14 pm

So the strings were used to ADD diffraction spikes purely for the visual effect (the intended effect being to "highlight" the brighter members)? (And there would have been no spikes otherwise since the telescope used was a refractor, not a reflector.)
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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by johnnydeep » Sat Apr 30, 2022 9:15 pm

AVAO wrote: Sat Apr 30, 2022 8:03 am
APOD Robot wrote: Sat Apr 30, 2022 4:05 am ...., the cluster was not resolved into its individual stars until telescopes were available.
JWST thinks that stars are burning :-)

Image
https://blogs.nasa.gov/webb/2022/04/28/ ... issioning/
Credit: NASA/STScI
"Burning"?
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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by AVAO » Sun May 01, 2022 5:13 am

johnnydeep wrote: Sat Apr 30, 2022 9:15 pm
AVAO wrote: Sat Apr 30, 2022 8:03 am
APOD Robot wrote: Sat Apr 30, 2022 4:05 am ...., the cluster was not resolved into its individual stars until telescopes were available.
JWST thinks that stars are burning :-)

Image
https://blogs.nasa.gov/webb/2022/04/28/ ... issioning/
Credit: NASA/STScI
"Burning"?
I think the JWST will reveal that much more stars have tails of dust than we think.
And in many cases these will only be visible in the IR and with a high IR sensitivity of the instrument.
The question for me is what is the reason for this?
When stars start to develop strong "plumes of smoke", could this be due to "incomplete burning processes" at the end of their life?

I dont't know, if AE Aurigae is a good example for that...
Image
Runaway star AE Aurigae
Creator: Adam Block
Copyright by Creator(s), Mount Lemmon SkyCenter, and University of Arizona
https://skycenter.arizona.edu/astrophotography/ic0405

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by Chris Peterson » Sun May 01, 2022 5:21 am

AVAO wrote: Sun May 01, 2022 5:13 am I think the JWST will reveal that much more stars have tails of dust than we think.
And in many cases these will only be visible in the IR and with a high IR sensitivity of the instrument.
The question for me is what is the reason for this?
When stars start to develop strong "plumes of smoke", could this be due to "incomplete burning processes" at the end of their life?
What is "incomplete burning" when stars don't burn?
Chris

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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by Ann » Sun May 01, 2022 6:36 am

AVAO wrote: Sun May 01, 2022 5:13 am
johnnydeep wrote: Sat Apr 30, 2022 9:15 pm
AVAO wrote: Sat Apr 30, 2022 8:03 am

JWST thinks that stars are burning :-)

Image
https://blogs.nasa.gov/webb/2022/04/28/ ... issioning/
Credit: NASA/STScI
"Burning"?
I think the JWST will reveal that much more stars have tails of dust than we think.
And in many cases these will only be visible in the IR and with a high IR sensitivity of the instrument.
The question for me is what is the reason for this?
When stars start to develop strong "plumes of smoke", could this be due to "incomplete burning processes" at the end of their life?

I dont't know, if AE Aurigae is a good example for that...
Image
Runaway star AE Aurigae
Creator: Adam Block
Copyright by Creator(s), Mount Lemmon SkyCenter, and University of Arizona
https://skycenter.arizona.edu/astrophotography/ic0405
Stars sustain themselves by fusing lighter elements into heavier elements and extracting energy while doing so, thus holding themselves up against the forces of gravity (and preventing themselves from collapsing, as the energy they have extracted is flowing outward, thus counteracting gravity that tries to make the stars collapse).

When stars have reached advanced stages of fusion - i.e., when they have used up the hydrogen in their cores and started fusing heavier elements in shells around their cores - then a relatively few of them can turn into carbon stars that are indeed strikingly red from "soot".
Wikipedia wrote:

A carbon star (C-type star) is typically an asymptotic giant branch star, a luminous red giant, whose atmosphere contains more carbon than oxygen. The two elements combine in the upper layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere, leaving carbon atoms free to form other carbon compounds, giving the star a "sooty" atmosphere and a strikingly ruby red appearance.

AE Aurigae, on the other hand, is not a carbon star, and it is not "smoking". AE Aurigae is a hot main sequence star, fusing hydrogen to helium in its core.

AE Aurigae is a runaway star:

Runaway stars AE Aur Mu Col and 53 Ari Stellarium.png
Sky & Telescope wrote:

Not only do Mu Col and AE Aur share the same 230,000 mph (100 km/sec) space velocity, they're racing away from one another in almost exactly opposite directions. Just as we trace meteor trails backwards to their radiant, we can trace the paths of Mu Col and AE Aur 2.5 million years back in time. They "meet" in the rich, star-forming regions highlighted by today's Orion Nebula. Today, they're 1,600 light-years apart. Back then, the nebula had only begun to emerge from darkness, awoken by the flickering light of its earliest suns...

It's thought that Mu Col and AE Aur once shared company as a binary system that collided or strayed too close to another binary pair. Complicated gravitational interactions ensued, breaking the binary's bond and flinging the stars into space as "runaways" while leaving the other binary intact, still lurking near the scene of the crime.
So AE Aur is racing through space at 100 km/sec. It has very recently blundered into cloud of gas and dust that just happened to lie in its path. And because AE Aur is so hot, 33,000 K, it ionizes the hydrogen in the cloud, making it glow red.

What are the bluish tendrils of the Flaming Star Nebula (which is the name of the nebula that AE Aur is lighting up)? Those tendrils are made of ordinary space dust.


The image above shows a cosmic dust particle. Cosmic dust particles are typically the right size to collectively reflect blue light at some 400 nm, making cosmic dust either look blue (as in the Pleiades nebulas), when the blue light is reflected our way, or either reddish or dark (as in the dust lane of the Milky Way) because the blue light is reflected away. Look at this image by Michael Skrutskie to see how dust reddening works in space.

Anyway. Look at the dust particle again. As you can see, it is rather fluffy. In the vicinity of a torrent of ultraviolet photons and a strong stellar wind from stars as hot as AE Aur, such dust particles are typically "cooked" to a considerably smaller size, so that they can't reflect the blue light from hot stars. Why do we see these light-reflecting tendrils of fluffy dust particles around AE Aur?

Answer: The dust tendrils have survived because AE Aur is passing through this cloud so quickly. AE Aur has undoubtedly destroyed huge numbers of dust motes on its way through the cloud, but a sufficient number of dust particles survive to reflect AE Aur's blue light.

But why does the dust seem to concentrate right in front of AE Aur itself? It's probably because AE Aur is acting like a snowplow, sweeping up dust in front of it in its mad race through the cloud of gas and dust that AE Aur has turned into a nebula of its own making.

Ann
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Last edited by Ann on Sun May 01, 2022 9:34 am, edited 2 times in total.
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Re: APOD: M44: The Beehive Cluster (2022 Apr 30)

Post by AVAO » Sun May 01, 2022 7:33 am

Ann wrote: Sun May 01, 2022 6:36 am
AVAO wrote: Sun May 01, 2022 5:13 am
johnnydeep wrote: Sat Apr 30, 2022 9:15 pm

"Burning"?
I think the JWST will reveal that much more stars have tails of dust than we think.
And in many cases these will only be visible in the IR and with a high IR sensitivity of the instrument.
The question for me is what is the reason for this?
When stars start to develop strong "plumes of smoke", could this be due to "incomplete burning processes" at the end of their life?

I dont't know, if AE Aurigae is a good example for that...
Image
Runaway star AE Aurigae
Creator: Adam Block
Copyright by Creator(s), Mount Lemmon SkyCenter, and University of Arizona
https://skycenter.arizona.edu/astrophotography/ic0405
Stars sustain themselves by fusing lighter elements into heavier elements and extracting energy while doing so, thus holding themselves up against the forces of gravity (and preventing themselves from collapsing, as the energy the have extracted is flowing outward, thus counteracting gravity what tries to make the stars collapse).

When stars have reached advanced stages of fusion - i.e., when they have used up the hydrogen in their cores and started fusing heavier elements in shells around their cores - then a relatively few of them can turn into carbon stars that are indeed strikingly red from "soot".
Wikipedia wrote:

A carbon star (C-type star) is typically an asymptotic giant branch star, a luminous red giant, whose atmosphere contains more carbon than oxygen. The two elements combine in the upper layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere, leaving carbon atoms free to form other carbon compounds, giving the star a "sooty" atmosphere and a strikingly ruby red appearance.

AE Aurigae, on the other hand, is not a carbon star, and it is not "smoking". AE Aurigae is a hot main sequence star, fusing hydrogen to helium in its core.

AE Aurigae is a runaway star:

Runaway stars AE Aur Mu Col and 53 Ari Stellarium.png
Sky & Telescope wrote:

Not only do Mu Col and AE Aur share the same 230,000 mph (100 km/sec) space velocity, they're racing away from one another in almost exactly opposite directions. Just as we trace meteor trails backwards to their radiant, we can trace the paths of Mu Col and AE Aur 2.5 million years back in time. They "meet" in the rich, star-forming regions highlighted by today's Orion Nebula. Today, they're 1,600 light-years apart. Back then, the nebula had only begun to emerge from darkness, awoken by the flickering light of its earliest suns...

It's thought that Mu Col and AE Aur once shared company as a binary system that collided or strayed too close to another binary pair. Complicated gravitational interactions ensued, breaking the binary's bond and flinging the stars into space as "runaways" while leaving the other binary intact, still lurking near the scene of the crime.
So AE Aur is racing through space at 100 km/sec. It has very recently blundered into cloud of gas and dust that just happened to lie in its path. And because AE Aur is so hot, 33,000 K, it ionizes the hydrogen in the cloud, making it glow red.

What are the bluish tendrils of the Flaming Star Nebula (which is the name of the nebula that AE Aur is lighting up)? Those tendrils are made of ordinary space dust.


The image above shows a cosmic dust particle. Cosmic dust particles are typically the right size to collectively reflect blue light at some 400 nm, making cosmic dust either look blue (as in the Pleiades nebulas), when the blue light is reflected out way, or either reddish or dark (as in the dust lane of the Milky Way) because the blue light is reflected away. Look at this image by Michael Skrutskie to see how dust reddening works in space.

Anyway. Look at the dust particle again. As you can see, it is rather fluffy. In the vicinity of a torrent of ultraviolet photons and a strong stellar wind from stars as hot as AE Aur, such dust particles are typically "cooked" to a considerably smaller size, so that they can't reflect the blue light from hot stars. Why do we see these light-reflecting tendrils of fluffy dust particles around AE Aur?

Answer: The dust tendrils have survived because AE Aur is passing through this cloud so quickly. AE Aur has undoubtedly destroyed huge numbers of dust motes on its way through the cloud, but a sufficient number of dust particles survive to reflect AE Aur's blue light.

But why does the dust seem to concentrate right in front of AE Aur itself? It's probably because AE Aur is acting like a snowplow, sweeping up dust in front of it in its mad race through the cloud of gas and dust that AE Aur has turned into a nebula of its own making.

Ann
Thank's Ann

Okk. I understand what you mean.
Your explanations are great and helpful...
... as always!

Jac