Category Archives: starbirth

Hubble Space Telecope, Orion Nebula, starbirth

Finding Cosmic Favorites in Hubble’s View

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I’m celebrating the 30th anniversary of Hubble’s launch to orbit by looking at some favorites that the telescope has studied. Of all the objects it has observed (literally billions of things in the sky), one of my favorites is the Orion Nebula. It’s in the constellation Orion (which is setting earlier in the April night skies). The nebula is really part of a larger collection of clouds of gas and dust called the “Orion Molecular Complex”. What we see is the most easily visible to the naked eye. And, of course, the nebula has been observed from the ground from many other facilities, too. For example, the National Radio Astronomy Observatory (NRAO) has looked at it in radio frequencies to study other structures.


Hubble’s Orion

So, most of us have seen the Orion Nebula through Hubble’s eye. It’s got four very bright stars at its center, called “the Trapezium”. There are many other newborn stars in the region. The nebula also has proplyds. That’s short for “protoplanetary disks”. Those are young stars with cocoons of dust around them, and in which planets are likely forming. All this splendor is only 1,500 light-years away from us. That’s very close by, in cosmic terms. Almost in the galactic back yard.

a Hubble Space Telescope view of the Orion Nebula.
The Orion Nebula as seen by Hubble Space Telescope. Courtesy NASA/ESA/STScI

Hubble’s Multi-wavelength View

Hubble has looked at the Orion Nebula in various wavelengths of light. The most revealing view one is infrared. It allows scientists’ gaze to penetrate the clouds of gas and dust that envelope some of the most interesting features.

If you could ride through the nebula in a ship equipped with infrared “eyes”, here’s what a flight through the nebula would resemble. There are what looks like ‘caves’ and ‘inlets’ carved out of the glowing clouds that make up the nebula. Those were carved out by ultraviolet radiation from hot young stars that appear blueish in this view. But, the beauty of infrared is that it shows lower-temperature objects. That includes faint stars that we wouldn’t normally see.

Hubble’s Look at Starbirth

The Orion Nebula gives us a pretty good and up-close view of starbirth. It ranges from the earliest young stellar objects to hot blue newborns. And, future solar systems that lie hidden inside the proplyds for our distant descendants to study. That makes it one of the best laboratories for astronomers to study the birth and evolution of stars and planets. It’s truly a cosmic treasure.

galactic history, galaxies, Herschel Space Telescope, starbirth

Cosmic Fireworks

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Big News in Distant Galaxies

You know that saying about how time is the universe’s way of keeping everything from happening at once? Well, there’s a lot happening in astronomy news today, almost all at once. So, the universe is flinging cool new stuff at us.

First, take a gander at this image. It’s an artist’s concept of what galaxies in the early universe were doing about 13 or so billion years ago.

 

Galaxies in the early universe grew fast by rapidly making new stars. Such prodigious star formation episodes, characterized by the intense radiation of the newborn stars, were often accompanied by fireworks in the form of energy bursts caused by the massive central black hole accretion in these galaxies. This discovery was made by a group of astronomers led by Peter Barthel of the Kapteyn Institute of the University of Groningen in the Netherlands. (Credit: ESA/NASA/RUG/MarcelZinger)

Yep, they were making stars at a prodigiously fast rate, more rapidly than many galaxies do today. By comparison, our Milky Way’s star birth factories create at an average rate of one new star a year. Ours is a pretty quiet galaxy in that regard. And, while we do have a black hole at the center of the galaxy, compared to other galaxies’ very busy black holes, ours is pretty tame. Only occasionally does it capture a star or gas cloud and gobble it up.

Now, if you look at more active galaxies, you see more  star formation. And these busy galaxies were much more common in the early universe.  So, it makes sense that astronomers would find galaxies at that time busily baking up stars. Quasars and radio galaxies are prime examples of these active galactic denizens.  And, observing them is easy due to their bright radiation, which can be detected over huge distances. Essentially, these active galaxies are easily detected through their luminous radio, ultraviolet or x-ray radiation, which results from steady accretion on to their massive central black holes.

These exotic galaxies are getting a lot of attention from the Herschel Telescope, which is sensitive to far-infrared wavelengths of light (which indicate heat radiation). A group of astronomers in the Netherlands has used it to study star birth in distant galaxies.  Basically, it looks for heat radiation generated by star and planet formation in our own galaxy, and also studies the same radiation from complete galaxies.  If a distant object is emitting strong levels of far-infrared radiation, then it’s a sure bet that the galaxy is undergoing massive amounts of star formation. And, by massive, I mean creating hundreds of stars each year.

These busy galaxies also have strong signals in radio frequencies, emanating from their central black holes. The black holes are busy growing (accreting mass and perhaps even merging), at the same time their host galaxies are creating whole batches of hot young newborn stars.  And all of it is happening billions of light-years away, showing us galaxies in some of the earliest epochs of the universe.

The take-home message here is that these kinds of active galaxies existed early in cosmic history.  They’re among the largest, most distant, most powerful and most spectacular objects in the universe. And, they give astronomers a look at what massive normal galaxies may have looked like in their infancy as they balanced the action of growing black holes at their hearts with the demands of star birth in other regions.  These are the kind of “baby pictures” of infant galaxies that give astronomers a deeper understanding of what happened “way back when” at a time when the universe was a baby.