Spitzer Telescope Discovers Planets Via Infrared

DirtyJ writes "Astronomers using the Spitzer Space Telescope have for the first time discovered two extrasoloar planets by directly detecting light from the planets themselves. Usually planets are discovered by indirectly inferring their presence from the wobble of star they orbit, but Spitzer has been able to directly detect these objects at Infrared wavelengths. Nifty conceptual images and videos are available."

Comments

Typo

[someguy456]

the proper term for a planet outside of the Sol solar system is "extrasolar"

not discovered, but observed

[heidi]

the planets are not newly discovered. they were previously known, but not directly imaged before.

Spitzer

[someguy456]

Is anyone else interested in the techical specifications of the Spitzer? I hadn't heard of it till today...

from About Spitzer

The Spitzer Space Telescope (formerly SIRTF, the Space Infrared Telescope Facility) was launched into space by a Delta rocket from Cape Canaveral, Florida on 25 August 2003. During its 2.5-year mission, Spitzer will obtain images and spectra by detecting the infrared energy, or heat, radiated by objects in space between wavelengths of 3 and 180 microns (1 micron is one-millionth of a meter). Most of this infrared radiation is blocked by the Earth's atmosphere and cannot be observed from the ground. Consisting of a 0.85-meter telescope and three cryogenically-cooled science instruments, Spitzer is the largest infrared telescope ever launched into space

Re:Spitzer

[astrobabe]

As someone who works who runs the Spitzer Helpdesk-

Thank you for reading the documentation!

And I'm a bit dissappointed people still haven't heard of us.

We launched in August 2003 and have been in science operations since December 2003. We have an approximately 5 year operational life time though the IRAC instrument may still be useable with only passive cooling once we run out of cryogen.

Re:Spitzer

[CanSpice]

Glad to see that the uninformed are still able to type. Kudos!

Infrared pictures are just not as pretty as those made in visible light.

Oh really?

And all pretty cosmic phenomena Spitzer can see are also observable by the Hubble telescope.

Not entirely true, as they operate over different wavelength bands. Spitzer operates in the mid- to far-infrared, whereas the longest wavelengths Hubble can view are in the near-infrared. Different wavelengths view different processes and different objects. Did you ever stop to think why there are different types of telescopes? It's because what's revealed in one waveband is invisible in others.

That, and perhaps the fact that the revelation that starts are, indeed, hot, was not a groundbreaking enough discovery to move the Spitzer into the visible spectrum.

This sentence makes absolutely no sense at all.

Re:Spitzer

[MattHaffner]

Infrared pictures are just not as pretty as those made in visible light.

I beg to differ. And I'm an optical astrnomer.

Nearly all PR images released by professional astronomers (and many by amateurs)--especially NASA--are not "true color". Nearly every multi-color image you see is from multiple actual observations that are combined in an image processing program. How "pretty" you want to make them is partly dependent on how much time, experience, and (frankly) money you have to spend on them. Keep in mind that "prettifying" pictures does not necessarily make them better for the science.

And all pretty cosmic phenomena Spitzer can see are also observable by the Hubble telescope.

Absolutely false.

Interstellar dust attenuates light, especially in the plane of the Milky Way. The survey project I linked to above penetrates much further than any visible light instrument can. And they only use 2 second integrations. Deeper, focused observations can detect distant gas and stars even better.

article is DUI on the actual technique

[OneOver137]

While they did discover them using IR, the technique was looking at eclipse intensity depth rather than direct observation. Good stuff though!

Re:Ob-Infrared-Ditty

[ajs]

Please, if you're going to snag the text, cite it:

Now the world has gone to bed,
Darkness won't engulf my head.
I can see by infra-red.
How I hate the night.

Now I lay me down to sleep,
Try to count electric sheep.
Sweet dream wishes you can keep,
How I hate the night.

Life, the Universe and Everything
by Douglas Adams, 1952-2001

Further info on Spitzer and the extrasolar planets

[astrobabe]

Yes Spitzer has been in science operations for over a year now. These detections were made with the two imagers- IRAC and MIPS. IRAC is the shorter wavelength camera (the observations were done at 8 microns) and MIPS the longer wavelength camera (observations done at 24 microns). Both planets are approximate 1000 degrees Kelvin and are Jupiter class with respect to mass.HD 209458b is 0.68 times the mass of Jupiter and has a radius about 1.35 times Jupiter's. The second planet- TrES1 has a mass equal to 0.76 Jupiter masses and is 1.04 times the radius of Jupiter. (and I do work for Spitzer and knew about these discoveries about 2 months ago when they first came into our Helpdesk which i run)

Re:IR temperature reading?

[Anonymous Coward]

Using infrared satellite imagery, cloud tops on Earth show up generally between -20 and -80 C, with higher cloud tops meaning colder temperatures.

Not 100% true...

[Pi_0's don't shower]

Although there is certainly no debate about these two objects being extrasolar planets, it is not the case that they were DISCOVERED using infrared. They were known extrasolar planets that were imaged in the IR using the spitzer telescope. Incidentally, they are not even the first pictures of extrasolar planets, as there is a nice one here from September of last year, that was reported on slashdot.

Re:Planet "X"

[CanSpice]

If and when the Hubble is updated, could this type of gear be added, or orbited in tandem, to allow both visual and infared examination of space?

The Hubble Space Telescope already has infrared capabilities, just not at the longer wavelengths that Spitzer can do. The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is an instrument on HST, and it can go as long as 2.5 microns, whereas Spitzer observes from roughly 3 to 180 microns.

Uh, that's not how they detect planets

[StateOfTheUnion]

I don't think that extrasolar planets are detected by occlusion of starlight. I think they are detected by the planet's gravity wobbling the star as the planet orbitx the star and exerts its gravitational pull. There are many sites online about this . . . here's one.

From the site: There are two basic methods of detecting a planet's gravitational influence on its star:

* Astrometric Detection

* Radial Velocity Detection

The first method - Astrometry - was hinted at in the previous paragraph. We observe a star and measure its position relative to distant background stars (hence the word "metric" in the name). As an orbiting body tugs at its companion star, we observe a change in position of the star. Measurements of a periodic change in position, back and forth, can indicate that something is possibly orbiting the star. Careful analysis of these measurements can tell us about the orbiting object.

The second method - Radial Velocity - is a completely different kind of measurement, but relies upon the same principle. That is, gravity. As an orbiting body tugs on its companion star, the light from the star will experience a Doppler shift. If the planet pulls the star slightly away from us on Earth, the starlight will be shifted towards longer wavelengths and appear more red; pulled slightly towards Earth, the starlight is shifted towards shorter wavelengths to appear more blue. To accurately measure this Doppler shift, we chose a known spectral line and observe its shift from red to blue and back.

Re:Uh, that's not how they detect planets

[DerekLyons]

I don't think that extrasolar planets are detected by occlusion of starlight.

In fact... They are. (IIRC it was one of the first methods proposed to search for extrasolar planets, because brightness can easily be measured, while precise angular position is a Hard Problem.)

Google on planet detection by occultation. Also, this links page has numerous links, and is part of the website for the NASA Kepler mission. (A probe designed to search for extrasolar planets via occultation.)

Re:Uh, that's not how they detect planets

[Lars T.]

This German article lists a number of ways to detect planets. In addition the two you mentioned, they have the Pulsar-Timing-Method which can of course only find planets around Pulsars, Gravitational Microlensing, and the Transit-Timing-Method . And occlusion of starlight IS an important way to find planets.

Of course, you can always check this site for all extra-solar planets found, and method they were found with.

Re:IR temperature reading?

[deglr6328]

already done