Sept. 22, 2012

From large clouds to solar systems ... How do we get there?

Keely Finkelstein

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Molecular Cloud seen in visible & IR wavelengths:

Horsehead Nebula - Molecular Cloud

✤ A star forming region will look different depending on what wavelength of like you are observing it with.

✤ Different wavelength regimes, probe different parts of the cloud.

Horsehead Nebula - in optical - dust obscures star-forming activity

Horsehead Nebula - Molecular Cloud

✤ A star forming region will look different depending on what wavelength of like you are observing it with.

✤ Different wavelength regimes, probe different parts of the cloud.

Horsehead Nebula - in infrared - a hot thin layer of dust on edge of cloud glows

Horsehead Nebula - Molecular Cloud

✤ A star forming region will look different depending on what wavelength of like you are observing it with.

✤ Different wavelength regimes, probe different parts of the cloud.

Horsehead Nebula - in sub mm - both cooler dust & molecules glow

Horsehead Nebula - Molecular Cloud

✤ A star forming region will look different depending on what wavelength of like you are observing it with.

✤ Different wavelength regimes, probe different parts of the cloud.

Horsehead Nebula - in radio - also see cold dust & molecules glowing

An example - the Orion Molecular Cloud Complex

belt stars M42, Orion NebulaHorsehead Nebula

Horsehead is just one small part of the larger molecular cloud complex and the Orion Nebula

Orion Molecular Cloud Complex✤ The previous image of the Orion molecular cloud complex spans a

region that is 75 light years across

✤ Molecular gas (as mapped by CO emission) extends over even more of the space mapped out in previous image.

✤ The Orion molecular cloud complex is the nearest site of massive star formation to the Sun (at a distance of 1500 light years) & is considered a giant molecular cloud complex

✤ Other molecular cloud sites are closer to us, such as the Taurus Molecular Cloud complex at 300 light years away - but it is smaller and only low-mass stars are produced in it. Orion is the nearest site that is large enough to produce massive stars.

✤ The whole Orion complex has a mass of ~ 200,000 solar masses

Orion GMC in CO emission (at millimeter wavelengths)

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are needed to see this picture.

belt starsCO emission inOrion Nebula

CO emission inHorsehead Nebula

Full Extended CO map overlaid on Orion Constellation

Structures of Molecular Clouds

✤ Clouds are complex structures Clumps of varying sizes, often connected by filaments and surrounded by more tenuous material

✤ The clumps can be very large and dense and often when we look at them in visible light they look uniformly dark

✤ But observing them at other wavelengths, such as millimeter wavelengths, reveals that the insides of these clumps can be very structured & can contain one or more very dense cores

✤ It is out of these cores that stars are born

So how do we go from these Giant Molecular clouds to this . . . ?

Star Formation Role Play - You are the experts:

✤ You are all at a conference and your are the world’s experts in star and planet formation

✤ 8 teams of experts - divide into teams and each group of you are the world experts in some branch of astrophysics.

✤ You are all gathered together at a conference to determine how these giant molecular clouds can turn into multiple solar systems.

✤ After you have debriefed and discussed with your team, and you are confident in your area of expertise - go out and exchange information with other groups.

✤ Anything goes - you are allowed to form consortia with other teams, you can withhold info from other teams, you can mislead them . . . its the real research world out there.

Star Formation Role Play - You are the experts:

✤ But just remember that unless you are willing to share information with other groups, they will not share with you!

✤ You can’t show other teams your briefing papers, but must explain and to them what is on it verbally.

✤ Your goal is to make a coherent theory of star and planet formation.

✤ You don’t know enough to figure this out for yourselves! Go out and talk to some other groups to see if that helps fill in the gaps in your story!

✤ Once you think you have a theory, complete with timescales, and numbers, write it down and then teams will present to the whole group.

✤ But keep in mind, there’s not just one correct ranking with only the 8 expert areas - ideas and concepts may be interwoven and used in multiple steps. Try to come up with the best coherent theory!