New Discoveries *4* - ...Solar System, Deep Space, cont'd

Palomar · 2005-05-19 05:37:32

(see post above this one)

http://www.spacedaily.com/news/stellar-05m.html]Getting the most out of MOST

*Wow, you Canadians are rocking the house with that space telescope! :band: Congratulations Canada!!

*Eta Bootis has been discovered to be ringing out of tune. It is roughly 2.5 billion l/y distant, "in" the constellation of Bootis (if you know that constellation, you've seen this star with the unaided eye). It's 2.5 billion years old, half the age of Sol, yet possesses twice the size and mass of Sol. It is also entering the red giant phase.

MOST has detected oscillations in the brightness of eta Bootis caused by sound waves bouncing around inside the star.
Comparing the oscillation frequencies to computer models reveals information about the star's otherwise invisible interior, just as you can tell by the sound alone whether you are listening to a stringed instrument like a violin or a brass instrument like a trumpet.
But as Dr. Guenther reveals, "My choir of theoretical star models are slightly out of tune compared to eta Bootis. Eta Bootis is telling us that we need to tweak our computer models."

MOST is the first space telescope "designed explicity" to study stellar oscillations. It's doing a marvelous job!

--Cindy

Palomar · 2005-05-21 12:48:39

http://antwrp.gsfc.nasa.gov/apod/ap020618.html]Question: How can a round star make a square nebula?

*Exquisite.

Is IC 4406.

Evidence indicates that IC 4406 is likely a hollow cylinder, with its square appearance the result of our vantage point in viewing the cylinder from the side. Were IC 4406 viewed from the top, it would likely look similar to the Ring Nebula.

Hot gas flows out the ends of the cylinder, while filaments of dark dust and molecular gas lace the bounding walls.

--Cindy

Palomar · 2005-05-23 06:58:54

http://www.space.com/imageoftheday/imag … l]Recycled Stars -- NGC 6559

*"In" the constellation of Sagittarius. Young stars evolved from the remains of stellar ancestors.

Molecular clouds of material cast out during the deaths of earlier stars slowly coalesce into stellar newborns, which blow out unused gas into the open oyster shell-like shape seen above.

--Cindy

Palomar · 2005-05-24 06:32:52

http://antwrp.gsfc.nasa.gov/apod/ap050524.html]Swirls & Stars in IC 4678

*Nice, huh? This starfield spans 25 light years. It's aprox 5000 l/y distant. Towards Sagittarius. Lots of reddish highlights and the pale purple reflection nebula sets it all off.

The dark absorption nebula to the right reminds me of a bird in flight, seen in full silhouette.

--Cindy

Palomar · 2005-05-25 05:16:17

*An abstract being hosted at spaceref.com regarding Triton:

Constraints on the Orbital Evolution of Triton
Authors: Matija Cuk, Brett J. Gladman
Comments: 10 pages, 4 figures, accepted for ApJL
We present simulations of Triton's post-capture orbit that confirm the importance of Kozai-type oscillations in its orbital elements. In the context of the tidal orbital evolution model, these variations require average pericenter distances much higher than previously published, and the timescale for the tidal orbital evolution of Triton becomes longer than the age of the Solar System. Recently-discovered irregular satellites present a new constraint on Triton's orbital history. Our numerical integrations of test particles indicate a timescale for Triton's orbital evolution to be less than $10^5$ yrs for a reasonable number of distant satellites to survive Triton's passage. This timescale is inconsistent with the exclusively tidal evolution (time scale of $>10^8$ yrs), but consistent with the interestion with the debris from satellite-satellite collisions. Any major regular satellites will quickly collide among themselves after being perturbed by Triton, and the resulting debris disk would eventually be swept up by Triton; given that the total mass of the Uranian satellite system is 40% of that of Triton, large scale evolution is possible. This scenario could have followed either collisional or the recently-discussed three-body-interaction-based capture.

http://www.spaceref.com/news/viewsr.htm … 35]Article appears here. Other text formats available.

--Cindy

Palomar · 2005-05-25 08:14:28

http://antwrp.gsfc.nasa.gov/apod/ap020725.html]Little dynamo

*Dwarf galaxy NGC 1569. Is 7 million l/y distant, "in" the constellation of Camelopardalis. It's still odd to consider that dwarf galaxies are the most common type of galaxies. :-\

This is a false-color x-ray image from Chandra. Discusses heavy elements and that recent findings are contributing to the notion that dwarf galaxies "are largely responsible for heavy elements in intergalactic space."

NGC 1569 is undergoing bursts of star formation and experiencing many supernovae.

For astronomers, elements other than hydrogen and helium are sometimes considered to be simply "heavy elements". It's understandable really, because even lumped all together heavy elements make up an exceedingly small fraction of the Universe. Still, heavy elements can profoundly influence galaxy and star formation ... not to mention the formation of planets and people ... NGC 1569 is surrounded by x-ray emitting clouds of gas thousands of light-years across. The gas has recently been observed to contain significant concentrations of astronomers' heavy elements such as oxygen, silicon, and magnesium ... The furious cosmic activity has heated the expanding gas clouds to temperatures of millions of degrees while enriching them with newly synthesized heavy elements.

--Cindy

::EDIT:: Here's a http://antwrp.gsfc.nasa.gov/apod/ap040205.html]Regular light HST image of NGC 1569

The photo spans 1500 light years.

Two massive star clusters - youthful counterparts to globular star clusters in our own spiral Milky Way galaxy - are seen left of center

Palomar · 2005-05-25 09:55:53

http://antwrp.gsfc.nasa.gov/apod/ap001128.html]BZ Cam bow shock

*...and what a bow shock! Extraordinary image.

This binary system lies 2500 l/y distant, towards the constellation Camelopardalis.

BZ Cam's wind creates a large bow-shock as the system moves through surrounding interstellar gas.

--Cindy

Palomar · 2005-05-27 09:05:49

http://antwrp.gsfc.nasa.gov/apod/ap010203.html]Majestic: M100

*Majestic yes, and even that adjective falls short. Such blues and purples; lovely.

Is a galaxy in the Virgo Cluster of the Grand Design classification.

M100 is estimated to contain over 100 billion stars.

And likely many fabulous nebulae which we'll probably never see.

--Cindy

Palomar · 2005-05-27 09:32:53

*It's Galaxy Day :;): Refer to post above this one.

http://antwrp.gsfc.nasa.gov/apod/ap960810.html]Unusual Spiral Galaxy M66

Is largest of the Leo Triplet. Note its asymmetrical arms; they think the gravitational pull of another galaxy -- M65 -- caused the distortion.

In M66, intricate long dust lanes are seen intertwined with the bright stars that light up the spiral arms. Recent research indicates that M66 is unusual in that older stars are thought to heat up the dust in the galaxy's central bulge - a job attributed to young and hot stars in many other galaxies.

Is also famous for powerful Type Ia supernovae (aka hypernovae). [Refer to http://www.newmars.com/forums/viewtopic.php?t=3085]THIS thread -- "Singularity" -- , a post dated May 27, for an article discussing Type Ia supernovae in connection with GRB's.]

--Cindy

Palomar · 2005-05-27 10:33:40

*These discoveries from 1997, but is the first time I've seen them.

http://antwrp.gsfc.nasa.gov/apod/ap970414.html]Cometary ejecta "hoods"

Hale-Bopp's nucleus measured 25 miles in diameter. It was spinning at a rate of once every 12 hours. Parts of the surface were shooting away in jets. That ejecta made rings, or "hoods."

Cool.

-also-

http://antwrp.gsfc.nasa.gov/apod/ap961113.html]Seven Jets from Comet H-B

Of course this Ikonboard didn't exist at the time this comet passed us (and I wasn't yet online).

--Cindy

Palomar · 2005-05-28 06:01:49

http://antwrp.gsfc.nasa.gov/apod/ap0306 … ]Supernova Shockwave: NGC 2736

*Stunning. Aka the "Pencil Nebula," it is plowing through space at a speed of 500,000 kph. Originally its speed was millions of kph, but the weight of the gases has slowed it down. Is a portion of the Vela supernova remnant; the expanding shell of a star which supernovaed 11,000 years ago.

The photo shows only 1 light year's size of the entire VSNR which is 100+ light years in size.

The very bright star in the foreground certainly enhances the beauty. And it seems to have an "image echo" behind and to its right (the 2nd brightest star in the photo).

--Cindy

Palomar · 2005-05-28 06:50:15

http://antwrp.gsfc.nasa.gov/apod/ap030610.html]Zooming in on the First Stars

*Our Sol is thought to be a 3rd-generation star.

Pictured above at a scale of one light-month, a computer-generated model resolves the scale of the first stars, indicating clean cocoons that condensed into stars always over 30 times the mass of our Sun.

Article states no known stars around us appear to be composed of truly primordial gases because they have too many heavy elements.

1st-generation stars are believed to have come and gone only 200 million years after the Big Bang.

--Cindy

P.S.: Check out post above this one (Pencil Nebula/Supernova Shockwave).

Palomar · 2005-05-30 12:38:48

http://www.universetoday.com/am/publish … ]Andromeda Galaxy is 3 times larger...

*...than previously thought.

Former estimates were that M31 was 70,000 to 80,000 l/y across. Now they've discovered that figure is closer to 220,000+ l/y across.

M31 is 2 million l/y from our Milky Way Galaxy (and in the far future we're going to crash into each other).

The stars in question were previously believed to be part of M31's halo, and not part of its actual disc. However, those stars -are- members of M31's main disc.

The new dimensional measure is based on the motions of about 3,000 of the stars some distance from the disk that were once thought to be merely the "halo" of stars in the region and not part of the disk itself. By taking very careful measurements of the "radial velocities," the researchers were able to determine precisely how each star was moving in relation to the galaxy.
The results showed that the outlying stars are sitting in the plane of the Andromeda disk itself and, moreover, are moving at a velocity that shows them to be in orbit around the center of the galaxy. In essence, this means that the disk of stars is vastly larger than previously known.

-and-

Chapman says that further work will be needed to determine whether the extended disk is merely a quirk of the Andromeda galaxy, or is perhaps typical of other galaxies.

Study was undertaken by astronomers in France and the U.S.

--Cindy

Palomar · 2005-05-31 05:49:29

http://www.spaceref.com/news/viewpr.html?pid=16974]RX J0806.3+1527

*There are 3 threads this story could fit into. But as I'm mostly interested in the binary system itself, will put it here.

It's a binary system of white dwarf stars "orbiting each other in a death grip." The smallest known orbit of any binary system, the stars are a mere 50,000 miles apart (1/5 of the distance between Earth and Luna).

They're swirling closer together, traveling at a speed in excess of 1 million mph. But apparently they're closing in on each other rather slowly: Only 1.2 milliseconds per year. Hmmmmm.

The data indicate gravitational waves are carrying energy away from the star system at a prodigious rate, making it a prime candidate for future missions designed to directly detect these ripples in space-time.
Einstein's General Theory of Relativity predicted a binary star system should emit gravitational waves that rush away at the speed of light and cause the stars to move closer together. As the stars move closer together, the orbital period decreases, and it can be measured by Chandra.

The production of gravity waves will increase as the pair moves closer together, of course.

Each star is estimated to have half of Sol's mass, yet are the size of Earth.

I wonder what the minimum distance "tipping point" will be, i.e. at what distance will they dramatically increase their co-rotation and fall into each other.

--Cindy

::EDIT:: This pair orbits each other once every 321 seconds.

Palomar · 2005-05-31 06:17:16

http://www.spaceflightnow.com/news/n0505/30stars/]Eta Carinae

*Always interesting to get fresh dibs on this star. Is 10,000 l/y distant and was once the 2nd brightest star in the sky. It has 100 times the mass of Sol and is so large it's barely holding itself together. Astronomers are speculating that Eta Carinae may go supernova within our lifetime.

The Carina Nebula, in which it and nearly-as-massive stellar siblings reside, is a large nebula; nearly 200 l/y across.

Astronomers say that radiation and winds from Eta Carinae and its massive siblings ripped apart the surrounding cloud of gas and dust, shocking the new stars into being.

-also-

Previous visible-light images of this region, called the Carina Nebula, show cloudy finger-like pillars of dust, all pointing toward Eta Carinae at the center. Spitzer's infrared eyes cut through much of this dust to expose incubating stars embedded inside the pillars, as well as new star-studded pillars never before seen.

-a family thing-

When massive stars like these are born, they rapidly begin to shred to pieces the very cloud that nurtured them, forcing gas and dust to clump together and collapse into new stars. The process continues to spread outward, triggering successive generations of fewer and fewer stars. Our own Sun may have grown up in a similar environment.
The new Spitzer image offers astronomers a detailed "family tree" of the Carina Nebula. At the top of the hierarchy are the grandparents, Eta Carinae and its siblings, and below them are the generations of progeny of different sizes and ages.

--Cindy

Palomar · 2005-05-31 09:23:30

http://www.spaceref.com/news/viewpr.html?pid=16975]New evidence for the violent demise of Sol-like stars

*This study involved Chandra, regarding planetary nebula NGC 40. It's aprox 3,000 l/y distant, towards the circumpolar constellation Cepheus (The King).

Says material spewed out from a dying star (in its final stages) at speeds of 2 million mph (wow!) can heat previously-spewed gas to the point where it begins emiting x-rays.

The study also offers new insight into how long the ejected gas around dying stars can persist in such a superheated state.
"This hot bubble of gas vividly demonstrates how, as a planetary nebula forms, the gas ejection process of the central, dying star becomes increasingly energetic," Kastner notes. "Mass ejection during stellar death can result in violent collisions that can heat the ejected gas up to temperatures of more than a million degrees."

Includes x-ray image. Some very bright orange areas in it.

--Cindy

Palomar · 2005-05-31 12:41:18

*I'm on a roll: My 4th post in this thread today. The universe is not enough! (Who wants eternity in Heaven? Let me roam the universe for aeons after I die, thanks).

http://www.universetoday.com/am/uploads … ll.jpg]See this? Pretty, huh?

-now with a bit of explanation-

http://antwrp.gsfc.nasa.gov/apod/ap971022.html]Antennae Galaxies

They are galaxies NGC 4038/39. 63 million l/y distant, "in" the constellation Corvus (The Crow).

A ground-based telescopic view (left) of the collision between the galaxies NGC 4038 and NGC 4039 reveals long arcing insect-like "antennae" of luminous matter flung from the scene of the accident. Investigators...sift[ing] through the cosmic wreckage near the two galaxy cores have recently announced the discovery of over a thousand bright young clusters of stars - the result of a burst of star formation triggered by the collision...
Dust clouds around the two galactic nuclei give them a dimmed and reddened appearance while the massive, hot, young stars of the newly formed clusters are blue.

--Cindy

Palomar · 2005-05-31 14:17:11

http://www.space.com/scienceastronomy/0 … sh.html]UV sky not as "quiet" as anticipated

*Article involves GALEX, which is studying galaxies. It's also seeing other things, including satellites and asteroids zipping by.

What's especially interesting are flares from distant stars. On April 4, 2004 GALEX was nearly overloaded when a star -- named GJ 3685A -- suddenly brightened x10,000. It maintained that brightness for 20 minutes. That star is an old red dwarf, 45 l/y distant. They later discovered 2 flares were involved, one following shortly after the other.

GALEX sees similar flares aprox once every two months.

These huge eruptions on the surface of a star can last a couple of minutes and typically cause 100-fold increase in UV output from the star.

A nice side-benefit to "merely" studying galaxies. :;):

--Cindy

Cobra Commander · 2005-06-02 06:07:00

Wouldn't want to lose this one to the void, locking it. Continue in New Discoveries 5.

New Mars Forums

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Re: New Discoveries *4* - ...Solar System, Deep Space, cont'd

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