Origins of Stars and Planets
When studying the origins of stars and planets, researchers at the Jet Propulsion Laboratory (JPL) use telescopes and advanced models to study the formation and death of stars, the physical and chemical processes in the spinning clouds of gas and dust where these stars are born, and the direct detection of planets around other stars. JPL collaborates with many groups that use telescopes to look for these conditions in the universe.
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| Simulated image of a nearby planetary system, as would be taken using an advanced coronagraph demonstrated at JPL. From Trauger and Traub, Nature 446 771 (2007). |
Planetary systems form from clouds of gas and dust orbiting the youngest stars. Studying this process requires making measurements with high spatial resolution and high contrast. Researchers in the origins of stars and planets research area use the Hubble, Spitzer, Herschel and Keck telescopes to study circumstellar matter and extrasolar planets. They are also leading the development of future telescope technologies that will open up the field for further study. Scientists in the space and astrophysical plasmas research area use computer modeling to translate the observational data into information about the processes that lead to forming stars and planets. Their models model the gas flows around young stars, the molecular reactions in the flows, the evolution of the solid material within and the emission of the radiation reaching our detectors.
This work comprises:
- Development of high contrast imaging technologies and future space telescope mission concepts, toward the goal of directly imaging planets around other stars. Laboratory coronagraphs have achieved contrasts exceeding billion-to-one in JPL space-simulating testbeds.
- High contrast imaging and interferometry experiments carried out at the Palomar and Keck observatories and at the Center for High Angular Resolution Astronomy (CHARA) array.
- Studies of planet formation in the circumstellar disks of young stars using ground and space observatories and computer modeling. Imaging with Hubble, in combination with Spitzer and Herschel measurements and detailed modeling, is leading to new insights into the disks' structure, composition and evolution.
- Numerical modeling to predict the planet formation signatures that will be detectable with future telescopes such as SOFIA and JWST.
- Characterization of the composition and structure of exoplanet atmospheres using infrared spectroscopy of transiting hot Jupiters.
- Studies of outflows from young stars and dying stars.
Selected Research Projects
Scientists in the origins of stars and planets research area work on a broad range of cutting-edge research projects, which include:
The Herschel Space Observatory
The European Space Agency (ESA)'s Herschel Space Observatory was launched on May 14, 2009, and with a primary mirror 3.5 m across, is the largest, most powerful infrared telescope ever flown in space. NASA and JPL's contributions to this groundbreaking observatory were comprised of two instruments: The Spectral and Photometric Imaging Receiver (SPIRE) and the Heterodyne Instrument for the Far Infrared (HIFI). SPIRE used "spider web bolometers," which are 40 times more sensitive than previous composite bolometers. SPIRE was developed at JPL by Dr. James Bock, SPIRE's Co-Investigator. Also onboard Herschel is the Heterodyne Instrument for the Far Infrared (HIFI) instrument. HIFI sensed radiation along six wavelength bands. NASA provided the mixers and local oscillator chains for the two highest bands, five and six; other local oscillator components for bands one through four; and power amplifiers. All instruments were cooled to -271ºC inside a cryostat filled with liquid superfluid helium. The mission finally exhausted its coolant on April 29, 2013.
The European Space Agency (ESA)'s Herschel Space Observatory was launched on May 14, 2009, and with a primary mirror 3.5 m across, is the largest, most powerful infrared telescope ever flown in space. NASA and JPL's contributions to this groundbreaking observatory were comprised of two instruments: The Spectral and Photometric Imaging Receiver (SPIRE) and the Heterodyne Instrument for the Far Infrared (HIFI). SPIRE used "spider web bolometers," which are 40 times more sensitive than previous composite bolometers. SPIRE was developed at JPL by Dr. James Bock, SPIRE's Co-Investigator. Also onboard Herschel is the Heterodyne Instrument for the Far Infrared (HIFI) instrument. HIFI sensed radiation along six wavelength bands. NASA provided the mixers and local oscillator chains for the two highest bands, five and six; other local oscillator components for bands one through four; and power amplifiers. All instruments were cooled to -271ºC inside a cryostat filled with liquid superfluid helium. The mission finally exhausted its coolant on April 29, 2013.
Herschel will continue communicating with its ground stations for some time now that the helium is exhausted, during which a range of technical tests will be performed. In May, 2013 it was propelled into its long-term stable parking orbit around the Sun.
Herschel was crucial in helping researchers study and understand:
- Birth of stars
- How galaxies formed and evolved in the early universe, and the nature of enormously powerful galactic energy sources
- The formation, evolution, and interrelationship of stars and the interstellar medium in the Milky Way and other galaxies
- Chemistry in our galaxy
- Molecular chemistry in the atmospheres of Mars and our solar system's comets and giant planets, and the nature of comet-like objects in the Kuiper belt beyond Neptune.
With its unique ability to detect light in the full 60-670 micron range, Herschel was successful in gathering information that has previously been unavailable.
The Exoplanet Exploration Program
Exoplanetary science is among the fastest evolving fields of today's astronomical research. Ground-based planet-hunting surveys alongside dedicated space missions (such as Kepler and CoRoT) are delivering an ever-increasing number of exoplanets.
Exoplanetary science is among the fastest evolving fields of today's astronomical research. Ground-based planet-hunting surveys alongside dedicated space missions (such as Kepler and CoRoT) are delivering an ever-increasing number of exoplanets.
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| Spectrum of transiting extrasolar planet, made with the Spitzer Space Telescope. From Swain et al., Astrophysical Journal 674 482 (2008). |
In January 2013, the NASA Astrophysics Division initiated the formation of two Science and Technology Definition Teams (STDTs) to study probe-scale (cost less than $1B) mission concepts for the direct detection of extrasolar planets orbiting nearby stars. One will study a concept based on a telescope with an internal coronagraph to generate the ultra-high contrast images needed for planet detection. A second study will use a pair of spacecraft flying in formation - a telescope and an external occulter (starshade). The STDTs are supported by a Design Team staffed by the Exoplanet Exploration Program. Final Reports from the studies will be due by January 2015.
The Hubble Space Telescope
Among its many discoveries, the Hubble Space Telescope has revealed the age of the universe to be about 13 to 14 billion years, much more accurate than the old range of anywhere from 10 to 20 billion years. Hubble played a key role in the discovery of dark energy, a mysterious force that causes the expansion of the universe to accelerate.
Among its many discoveries, the Hubble Space Telescope has revealed the age of the universe to be about 13 to 14 billion years, much more accurate than the old range of anywhere from 10 to 20 billion years. Hubble played a key role in the discovery of dark energy, a mysterious force that causes the expansion of the universe to accelerate.
Hubble has revealed galaxies in all stages of evolution, as well as protoplanetary disks, clumps of gas and dust around young stars that likely function as birthing grounds for new planets. It discovered that gamma-ray bursts — strange, incredibly powerful explosions of energy — occur in far-distant galaxies when massive stars collapse. And these are only a handful of its many contributions to astronomy.
The Hubble Space Telescope's science instruments -- its cameras, spectrographs, and fine guidance sensors -- work either together or individually to bring us stunning images from the farthest reaches of space.
One of these instruments, the Wide Field/Planetary Camera, was installed on the Hubble telescope when it was first launched into Earth orbit on a space shuttle on April 24, 1990. Scientists soon discovered, however, that a tiny error in the curvature of the space telescope's main mirror made it impossible to focus images sharply. Fortunately, JPL engineers determined that by changing the optics of the camera instrument, the telescope's problem could be overcome. The Wide Field and Planetary Camera 2 was installed on the Hubble telescope by astronauts on December 2, 1993. This brought Hubble's vision to perfect focus, and over the next few years the space telescope has relayed phenomenal pictures and made possible a variety of discoveries. The James Webb Space Telescope (JWST) could add to Hubble's discoveries, when it launches in 2018. JWST is a large, infrared-optimized space telescope that will find the first galaxies that formed in the early Universe, connecting the Big Bang to our own Milky Way Galaxy. JWST could peer through dusty clouds to see stars forming planetary systems, connecting the Milky Way to our own Solar System. Webb's instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range.
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| Star-forming region in Carina. Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI). |
Spitzer Telescope
The Spitzer Space Telescope (formerly SIRTF, the Space Infrared Telescope Facility) was launched into space by a Delta rocket from Cape Canaveral, Florida on August 25, 2003. During its 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.
The Spitzer Space Telescope (formerly SIRTF, the Space Infrared Telescope Facility) was launched into space by a Delta rocket from Cape Canaveral, Florida on August 25, 2003. During its 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. Infrared reveals information about the cooler objects in space, such as smaller stars which are too dim to be detected by their visible light, extrasolar planets, and giant molecular clouds. Also, many molecules in space, including organic molecules, have their unique signatures in the infrared.
Because infrared is primarily heat radiation, the telescope must be cooled to near absolute zero (-459 degrees Fahrenheit or -273 degrees Celsius) so that it can observe infrared signals from space without interference from the telescope's own heat. Also, the telescope must be protected from the heat of the Sun and the infrared radiation put out by the Earth. To do this, Spitzer carries a solar shield and will be launched into an Earth-trailing solar orbit. This unique orbit places Spitzer far enough away from the Earth to allow the telescope to cool rapidly without having to carry large amounts of cryogen (coolant).
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