APOD: Spitzer's Orion (2011 Sep 17)

[APOD Robot]

Spitzer's Orion

Explanation: Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This stunning false-color view spans about 40 light-years across the region, constructed using infrared data from the Spitzer Space Telescope. Compared to its visual wavelength appearance, the brightest portion of the nebula is likewise centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But the infrared image also detects the nebula's many protostars, still in the process of formation, seen here in red hues. In fact, red spots along the dark dusty filament to the left of the bright cluster include the protostar cataloged as HOPS 68, recently found to have crystals of the silicate mineral olivine within its protostellar envelope.

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[Boomer12k]

ooooooohhhh, pretty!!!! I want an infrared telescope!!!!


:~ ~ ~ ~ ~>>>>>><<<<< % -------Me with my new infrared telescope!!!!

[owlice]

I like this image a lot and am very happy to see it as an APOD!

[cketter]

I love the string of young stars dotting the dark crease on the left. I've never seen M42 quite like this. I can't wait to see what kind of IR images the James Webb Space Telescope will bring!
Also, check out this new Vesta video I found from spaceweather.com today. http://www.jpl.nasa.gov/video/index.cfm?id=1020
Very cool! They say that even higher resolution images are in store for October!

[orin stepanek]

In fact, red spots along the dark dusty filament to the left of the bright cluster include the protostar cataloged as HOPS 68, recently found to have crystals of the silicate mineral olivine within its protostellar envelope.

Click to view full size image

From Wikipedia, the free encyclopedia
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For the river in New Zealand, see Olivine River.
Olivine
General
Category Mineral Group
Chemical formula (Mg, Fe)2SiO4
Identification
Color Yellow to yellow-green
Crystal habit Massive to granular
Crystal system Orthorhombic
Cleavage Poor
Fracture Conchoidal – brittle
Mohs scale hardness 6.5–7
Luster Vitreous
Streak White
Diaphaneity Transparent to translucent
Specific gravity 3.27–3.37
Optical properties Biaxial (+)
Refractive index nα = 1.630–1.650
nβ = 1.650–1.670
nγ = 1.670–1.690
Birefringence δ = 0.040
References [1][2][3]

The mineral olivine (when gem-quality also called peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface.

The ratio of magnesium and iron varies between the two endmembers of the solid solution series: forsterite (Mg-endmember) and fayalite (Fe-endmember). Compositions of olivine are commonly expressed as molar percentages of forsterite (Fo) and fayalite (Fa) (e.g., Fo70Fa30). Forsterite has an unusually high melting temperature at atmospheric pressure, almost 1900 °C, but the melting temperature of fayalite is much lower (about 1200 °C). The melting temperature varies smoothly between the two endmembers, as do other properties. Olivine incorporates only minor amounts of elements other than oxygen, silicon, magnesium and iron. Manganese and nickel commonly are the additional elements present in highest concentrations.

Olivine gives its name to the group of minerals with a related structure (the olivine group) which includes tephroite (Mn2SiO4), monticellite (CaMgSiO4) and kirschsteinite (CaFeSiO4).

[bystander]

Also, check out this new Vesta video I found from spaceweather.com today. http://www.jpl.nasa.gov/video/index.cfm?id=1020
Very cool! They say that even higher resolution images are in store for October!

http://asterisk.apod.com/viewtopic.php?t=23647#p157738

[bystander]

http://asterisk.apod.com/viewtopic.php?f=31&t=23765
http://asterisk.apod.com/viewtopic.php?f=31&t=18931

[neufer]

Magnificent Frigatebird

<<The Magnificent Frigatebird (Fregata magnificens) was sometimes previously known as Man O'War, reflecting its rakish lines, speed, and aerial piracy of other birds. It spends days and nights on the wing, with an average ground speed of 10 km/hour, covering 223±208 km before landing. They alternately climb in thermals (as high as 2500 m) and descend to near the sea surface. The only other bird known to spend days and nights on the wing is the Common Swift.

The Magnificent Frigatebird is silent in flight, but makes various rattling sounds at its nest. The sharp outline of the wings may cause some observers to misidentify a Frigatebird as a modern featherless pterosaur. It is widespread in the tropical Atlantic, breeding colonially in trees in Florida, the Caribbean and Cape Verde Islands. It also breeds along the Pacific coast of the Americas from Mexico to Ecuador including the Galapagos Islands.

The Magnificent Frigatebird is 100 cm long with a 215 cm wingspan. Males are all black with a scarlet throat pouch (gular sac) which is inflated like a balloon in the breeding season. Although the feathers are black, the scapular feathers produce a purple iridescence when they reflect sunlight. Females are black, but have a white breast and lower neck sides, a brown band on the wings and a blue eye ring.

This species feeds mainly on fish, and also attacks other seabirds to force them to disgorge their meals. Frigatebirds produce very little oil and therefore do not land in the ocean. These birds do not swim and cannot walk well, and cannot take off from a flat surface. Having the largest wingspan to body weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week, landing only to roost or breed on trees or cliffs.>>

[NoelC]

Yeah, I wish I could afford an infrared space telescope too.

I especially like the way we can see through the dust clouds that make up the shape of the Running Man silhouette (not seen in the APOD) to the star behind that's illuminating it all...

This animation shows the APOD and a visible light image alternating, so you can easily see how different things look at the two different wavelengths. Click the image to see a larger animated one.



-Noel

[biddie67]

Noel - your animation really helps in visualizing the 2 different images - thanks.

A question about implications of the presence of olivines in HOPS 68 - other than confirming that the telescope, et.al. are helping to isolate such details, what does it's presence in a star mean compared to stars where it doesn't seem to be found?

Orin Stepanek's info above seems to say that a different mixture of elements might be present or different temperature patterns and outflow/inflow patterns might exist in this kind of star ???

[Chris Peterson]

A question about implications of the presence of olivines in HOPS 68 - other than confirming that the telescope, et.al. are helping to isolate such details, what does it's presence in a star mean compared to stars where it doesn't seem to be found?

Olivines are composed of common interstellar dust elements, so you'd normally expect to produce them given an environment with some mixing and moderate temperatures of ~2000°C. That describes many, if not most protostar outer regions. The suggestion with this observation is that the olivines are forming in the protostellar atmosphere, and then being carried by jets or winds outwards where they cool and crystalize, and then rain back down (and are destroyed).

I'm not sure anybody has looked closely enough at this mechanism to say if there are protostars where it doesn't occur. At this point, there is probably a huge observational bias. Olivine crystals may be present in the envelopes of all protostars... or not.

[Tszabeau]

This is one of the best of the best APODs and discussions ever. I hope my question doesn't sound altogether flippant but: could someone hear me scream in a nebula? In other words when a tree falls in a Nebula does it make a sound (provided someone's there to hear it)?

[David Theil]

Very nice, Noel. I don't know if you have a background in astro, but my former thesis adviser (and me too) used blinking between different wavelength images (even VERY different, like between visible bands and microwave) as tool for understanding relationships between structures. At a quick glance, your blink shows how some very faintly externally illuminated dust structures at the edge of the Trapezium bubble really light up in the IR. No doubt there is a lot more of information like that if you spend a lot of time looking.

Now a question for the group; has anyone seen a caption for the Spitzer image that explains what bands the RGB color channels are assigned to?

[thumlyly]

The image contains so many stars being formed within such a cloud of material, that something about the universe is shown to me in stark contrast. While all the stars are spinning on an axis, and everything around them is orbitting, and all that is orbitting within a galaxy if they are part of one, the nebula giving rise to the spinning stars is not spinning. So, what is spin, and when and how does spinning start?

Tiny entities like electrons spin and orbit, but molecules do not, nor what is made by molecules, until the size e.g. of the asteroid Vesta. Some moons, such as Earth's, do not spin but do orbit. And there is no indication that the universe of billions of spinning galaxies is itself spinning (though how that might be detected is a puzzle). Within the chaotic complexity of these nebulae, there are suggestions of inflationary expansion maybe, but not spinning. So does it take a density factor to initiate spinning, shared by atomic particles and planets but not rain clouds until they become hurricanes and not nebulae until they become a galaxy of their stars?

[neufer]

This is one of the best of the best APODs and discussions ever. I hope my question doesn't sound altogether flippant but: could someone hear me scream in a nebula? In other words when a tree falls in a Nebula does it make a sound (provided someone's there to hear it)?

At pressures below a millionth of an atmosphere the mean free path of gas molecules becomes longer than the size of your head and also longer than the wavelength of any sounds you might try to produce. Very large events like supernova are capable of producing very long wavelength sounds (and shock waves) but no one would hear a "tiny" tree fall over.

And Horton couldn't hear a "tiny" Who for similar reasons.

[bystander]

Now a question for the group; has anyone seen a caption for the Spitzer image that explains what bands the RGB color channels are assigned to?

Spitzer: Stars Adorn Orion's Sword
http://asterisk.apod.com/viewtopic.php?f=31&t=23765

Code: Select all

Color Mapping

Band      Wavelength 	Telescope		 Color
Infrared 	 3.6 µm 	 Spitzer IRAC 	Blue
Infrared 	 4.5 µm 	 Spitzer IRAC 	Teal
Infrared 	 8.0 µm 	 Spitzer IRAC 	Green
Infrared 	24.0 µm 	 Spitzer MIPS 	Red 

[Chris Peterson]

Tiny entities like electrons spin and orbit, but molecules do not, nor what is made by molecules, until the size e.g. of the asteroid Vesta.

Actually, quantum scale bodies like electrons don't spin in the same sense macroscopic bodies do. They have a property called "spin", but it would be a mistake to read too much into that word. Molecules certainly spin, however, unless they are held in place by external forces. Put a free molecule in space, and it will be spinning. As will any body made up of atoms or molecules, from just a few to any number.

Some moons, such as Earth's, do not spin but do orbit.

The Moon spins, with the same period as its orbit. All satellites spin.

And there is no indication that the universe of billions of spinning galaxies is itself spinning (though how that might be detected is a puzzle).

Nor is there any indication that it doesn't. The problem in part is one of definition. All the other object you refer to, from particles up to galaxies, are three-dimensional. The Universe is a four-dimensional structure, so comparisons become tricky.

Within the chaotic complexity of these nebulae, there are suggestions of inflationary expansion maybe, but not spinning. So does it take a density factor to initiate spinning, shared by atomic particles and planets but not rain clouds until they become hurricanes and not nebulae until they become a galaxy of their stars?

Everything is spinning. In some cases you have groups of things that are held together by other forces, and that prevents them from spinning independently of each other, that's all. Nebulas are spinning as well, although generally too slowly to notice many effects caused by it. Inside a nebula, you have all sorts of turbulent motion and spinning- it is precisely the spinning of local regions that results in the formation of stars.

[Tszabau]

... could someone hear me scream in a nebula? In other words when a tree falls in a Nebula does it make a sound (provided someone's there to hear it)?

At pressures below a millionth of an atmosphere the mean free path of gas molecules becomes longer than the size of your head and also longer than the wavelength of any sounds you might try to produce. Very large events like supernova are capable of producing very long wavelength sounds (and shock waves) but no one would hear a "tiny" tree fall over.

And Horton couldn't hear a "tiny" Who for similar reasons.

Excellent answer.

Therefore then, presumably, vice versa? Making us, simultanously, the Who AND the Horton? Quantum!

[viktorz]

The Magnificent Frigatebird is silent in flight, but makes various rattling sounds at its nest. The sharp outline of the wings may cause some observers to misidentify a Frigatebird as a modern featherless pterosaur. It is widespread in the tropical Atlantic, breeding colonially in trees in Florida, the Caribbean and Cape Verde Islands. It also breeds along the Pacific coast of the Americas from Mexico to Ecuador including the Galapagos Islands.

That bierd is amazing ))