Spitzer Liquid He Options

[ljk4-1]

Astrophysics, abstract
astro-ph/0602146

From: Donald F. Figer [view email]

Date: Tue, 7 Feb 2006 02:14:43 GMT (381kb)

Discovery of an Extraordinarily Massive Cluster of Red Supergiants

Authors: Donald F. Figer (RIT), John MacKenty, Massimo Robberto, Kester Smith (STScI), Francisco Najarro (CSIC), Rolf P. Kudritzki (UH), Artemio Herrero (IAC)

Comments: ApJ, accepted

We report the discovery of an extraordinarily massive young cluster of stars in the Galaxy, having an inferred total initial cluster mass comparable to the most massive young clusters in the Galaxy. Using {\it IRMOS}, {\it 2MASS}, and {\it Spitzer} observations, we conclude that there are 14 red supergiants in the cluster, compared with five, in what was previously thought to be the richest Galactic cluster of such stars. We infer spectral types from near-infrared spectra that reveal deep CO bandhead absorption that can only be fit by red supergiants. We identify a gap of $\Delta${\it K}$_s$$\sim$4 magnitudes between the stars and the bulk of the other stars in the region that can only be fit by models if the brightest stars in the cluster are red supergiants. We estimate a distance of 5.8~\kpc to the cluster by associating an OH maser with the envelope of one of the stars. We also identify a ``yellow'' supergiant of G6~I type in the cluster. Assuming a Salpeter IMF, we infer an initial cluster mass of 20,000 to 40,000~\Msun for cluster ages of 7-12~\Myr. Continuing with these assumptions, we find 80% of the intial mass and 99% of the number of stars remain at the present time. We associate the cluster with an x-ray source (detected by {\it ASCA} and {\it Einstein}), a recently discovered very high energy $\gamma$-ray source (detected by {\it INTEGRAL} and {\it HESS}), and several non-thermal radio sources, finding that these objects are likely related to recent supernovae in the cluster. In particular, we claim that the cluster has produced at least one recent supernova remnant with properties similar to the Crab nebula. It is not unlikely to find such a source in this cluster, given our estimated supernova rate of one per 40,000 to 80,000~{\it yr}.

http://arxiv.org/abs/astro-ph/0602146

[Jeff7]

If it is determined that Spitzer is of no use once the liquid helium is gone, what's going to be done with it? Send it on a decaying orbit into the sun or just sort of leave it dormant where it's at?

[tty]

If Spitzer is determined to be of no use once the liquid helium is gone, what's going to be done with it? Send it on a decaying orbit into the sun or just sort of leave it dormant where it's at?

Definitely not into the Sun. It requires an enormous Delta Vee to get there. The Sun is actually the most difficult place to reach in the Solar System, energy-wise.

tty

[Jeff7]

Definitely not into the Sun. It requires an enormous Delta Vee to get there. The Sun is actually the most difficult place to reach in the Solar System, energy-wise.

tty

Really? Crazy....is that just because of outward inertia from the revolution around the sun?

Alright, how about smacking it into the Moon Deep-Impact style? Or else into Earth's atmosphere.

I guess I just don't like the idea of it hanging out there as little more than space junk.

[ljk4-1]

Really? Crazy....is that just because of outward inertia from the revolution around the sun?

Alright, how about smacking it into the Moon Deep-Impact style? Or else into Earth's atmosphere.

I guess I just don't like the idea of it hanging out there as little more than space junk.

Could Spitzer be used as a "regular" telescope in some way? Does it have any other instruments that might perform, say solar and interplanetary observations?

Gravity Probe B can no longer perform its main function, but they are finding other uses for it as it is still active. I even recall the famous COBE satellite being used for some kind of satellite testing after it could no longer do major science work.

But let's not blast it from the skies like the USAF did to that poor satellite observing comets hitting the Sun, shall we?

http://heasarc.nasa.gov/docs/heasarc/missions/p78-1.html

http://cometography.com/lcomets/1979q1.html

http://www.svengrahn.pp.se/histind/ASAT/F15ASAT.html

http://www.edwards.af.mil/moments/docs_html/85-09-13.html

http://lasco-www.nrl.navy.mil/solwind.html

Regarding your "space junk" comment, some day those satellites still floating out in the void will be considered highly prized relics of the early Space Age by future exoarchaeologists.

[ljk4-1]

News Release: 2006-022 February 15, 2006

NASA's Spitzer Finds Violent Galaxies Smothered in 'Crushed Glass'

NASA's Spitzer Space Telescope has observed a rare population of colliding galaxies whose entangled hearts are wrapped in tiny crystals resembling crushed glass.

The crystals are essentially sand, or silicate, grains that were formed like glass, probably in the stellar equivalent of furnaces. This is the first time silicate crystals have been detected in a galaxy outside of our own.

"We were surprised to find such delicate, little crystals in the centers of some of the most violent places in the universe," said Dr. Henrik Spoon of Cornell University, Ithaca, N.Y. He is first author of a paper on the research appearing in the Feb. 20 issue of the Astrophysical Journal. "Crystals like these are easily destroyed, but in this case, they are probably being churned out by massive, dying stars faster than they are disappearing."

The discovery will ultimately help astronomers better understand the evolution of galaxies, including our Milky Way, which will merge with the nearby Andromeda galaxy billions of years from now.

"It's as though there's a huge dust storm taking place at the center of merging galaxies," said Dr. Lee Armus, a co-author of the paper from NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "The silicates get kicked up and wrap the galaxies' nuclei in giant, dusty glass blankets."

Silicates, like glass, require heat to transform into crystals. The gem-like particles can be found in the Milky Way in limited quantities around certain types of stars, such as our sun. On Earth, they sparkle in sandy beaches, and at night, they can be seen smashing into our atmosphere with other dust particles as shooting stars. Recently, the crystals were also observed by Spitzer inside comet Tempel 1, which was hit by NASA's Deep Impact probe

( http://www.spitzer.caltech.edu/Media/relea.../release.shtml).

The crystal-coated galaxies observed by Spitzer are quite different from our Milky Way. These bright and dusty galaxies, called ultraluminous infrared galaxies, or "Ulirgs," are swimming in silicate crystals. While a small fraction of the Ulirgs cannot be seen clearly enough to characterize, most consist of two spiral-shaped galaxies in the process of merging into one. Their jumbled cores are hectic places, often bursting with massive, newborn stars. Some Ulirgs are dominated by central supermassive black holes.

So, where are all the crystals coming from? Astronomers believe the massive stars at the galaxies' centers are the main manufacturers. According to Spoon and his team, these stars probably shed the crystals both before and as they blow apart in fiery explosions called supernovae. But the delicate crystals won't be around for long. The scientists say that particles from supernova blasts will bombard and convert the crystals back to a shapeless form. This whole process is thought to be relatively short-lived.

"Imagine two flour trucks crashing into each other and kicking up a temporary white cloud," said Spoon. "With Spitzer, we're seeing a temporary cloud of crystallized silicates created when two galaxies smashed together."

Spitzer's infrared spectrograph spotted the silicate crystals in 21 of 77 Ulirgs studied. The 21 galaxies range from 240 million to 5.9 billion light-years away and are scattered across the sky. Spoon said the galaxies were most likely caught at just the right time to see the crystals. The other 56 galaxies might be about to kick up the substance, or the substance could have already settled.

Others authors of this work include Drs. A.G.G.M. Tielens and J. Cami of NASA's Ames Research Center, Moffett Field, Calif.; Drs. G.C. Sloan and Jim R. Houck of Cornell; B. Sargent of the University of Rochester, N.Y.; Dr. V. Charmandaris of the University of Crete, Greece; and Dr. B.T. Soifer of the Spitzer Science Center.

The Jet Propulsion Laboratory manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center. JPL is a division of Caltech. Spitzer's infrared spectrograph was built by Cornell University, Ithaca, N.Y. Its development was led by Dr. Jim Houck.

http://www.spitzer.caltech.edu/Media/relea...6/release.shtml

[ljk4-1]

Distant inferno: Cornell astronomer finds galaxies that contain massive young stars in compact, cosmic globs

http://www.news.cornell.edu/stories/Feb06/...s.Spoon.lg.html

Feb. 15, 2006

By Lauren Gold
lg34@cornell.edu

The discovery makes the fiery environment within a typical spiral or starburst galaxy look almost pastoral. Cornell researchers using the Spitzer Space Telescope say distant galaxies contain an inferno of very young, massive and violently evolving stars, packed together in tiny but extremely powerful cosmic globs.

The key to the discovery, paradoxically, is in the presence of delicate, glittery crystalline silicates called Forsterite. These are glassy particles that exist in the debris disks of young stars and in the stellar wind of very old stars, but which have never before been observed in the mass of gas and dust known as the interstellar medium, or ISM, in the Milky Way or in any other galaxy.

The research, led by Cornell astronomer and Spitzer Fellow Henrik Spoon, will appear in the Feb. 20 issue of the Astrophysical Journal.

[ljk4-1]

NASA's Spitzer Makes Hot Alien World the Closest Directly Detected

http://www.spaceref.com/news/viewpr.html?pid=19084

"A NASA-led team of astronomers have used NASA's Spitzer Space Telescope to
detect a strong flow of heat radiation from a toasty planet orbiting a nearby star.
The findings allowed the team to "take the temperature" of the planet."

[ljk4-1]

TIME AND SPACE

- Spitzer Sees Back 9 Billion Years

http://www.spacedaily.com/reports/Spitzer_...lion_Years.html

Pasadena CA (SPX) Mar 21, 2006 - Astronomers have captured an image of the most
distant cluster of galaxies ever seen, located about 9 billion light-years away
from Earth – and photographed at a stage when the universe was only about
one-third of its present age.

[ljk4-1]

Review: The Last of the Great Observatories
---

The scientific work involved with a major NASA mission can pale in
comparison to the effort needed to actually build the spacecraft.

Jeff Foust reviews a new book that provides an insider's account of
the development of the Spitzer Space Telescope.

http://www.thespacereview.com/article/620/1

[Guest_Analyst_*]

This presentation says the LHe will last approx. 5 1/2 years, much longer than needed (2 1/2 years) for mission success and a little longer than the 5 years hoped for. There is also a possible extended "warm" mission mentioned.

Analyst

[mps]

NASA's Spitzer Telescope Warms Up To New Career

[MahFL]

Can anyone tell us how long Spitzer might operate for in its "warm" mission ?

[stevesliva]

Can anyone tell us how long Spitzer might operate for in its "warm" mission ?

I'm not sure how long the current funding lasts, but that's probably the primary determinant: funding. The cost of operating Spitzer for just these two channels was not viewed by everyone as worthy of the cost. They did reduce operating expenses a bunch, but I think they were pressed to get operating costs down even farther. I'd guess they might get pressed harder the next go-around. And so it goes. Up to the hopefully well-advised beancounters.

This site has some great info on what they plan to do:
http://ssc.spitzer.caltech.edu/mtgs/warm/

[NGC3314]

They do get advice from (in this case) a panel of astrophysicists (I've done it but not this round). This one was brutal - continuation of Chandra operations, the Spitzer warm mission, continuation of GALEX, WMAP, Swift, RXTE... were all on the table for competitive review. (Hubble seems to have been a separate budget line). The usual pattern is to try to keep missions going past their nominal lifetimes if healthy and productive, with the budget squeeze getting tighter and tighter the longer they go on. When one of the ongoing (extended) missions has a glitch, you can practically hear the knives come out at NASA headquarters, not to mention the operations centers of all the others.

Current funding is supposed to be for two years of warm operation, which keeps the two shortest wavelengths with the Infrared Array Camera going with almost no degradation (including some impressive survey programs). Since the helium ran out on May 15 (two weeks after a recent estimate), the funded warm mission starts now.