From JPL-Caltech: “Stellar Dust Survey Paves Way for Exoplanet Missions”



April 25, 2018

Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.

Doug Carroll
University of Arizona, Tucson

This artist’s concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system.

NASA’s Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present.

The movie [?’ begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight.

In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the “false dawn,” this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.)

In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

U Arizona Large Binocular Telescope, Mount Graham, Arizona, USA, Altitude 3,221 m (10,568 ft) The Large Binocular Telescope Interferometer, or LBTI, is a ground-based instrument connecting two 8-meter class telescopes on Mount Graham in Arizona to form the largest single-mount telescope in the world. The interferometer is designed to detect and study stars and planets outside our solar system Image credit: NASA/JPL-Caltech.

Veils of dust wrapped around distant stars could make it difficult for scientists to find potentially habitable planets in those star systems. The Hunt for Observable Signatures of Terrestrial Systems, or HOSTS, survey was tasked with learning more about the effect of dust on the search for new worlds. The goal is to help guide the design of future planet-hunting missions. In a new paper published in the Astrophysical Journal, HOSTS scientists report on the survey’s initial findings.

Using the Large Binocular Telescope Interferometer, or LBTI, on Mount Graham in Arizona, the HOSTS survey determines the brightness of warm dust floating in the orbital planes of other stars (called exozodiacal dust). In particular, HOSTS has studied dust in nearby stars’ habitable zones, where liquid water could exist on the surface of a planet. The LBTI is five to 10 times more sensitive than the previous telescope capable of detecting exozodiacal dust, the Keck Interferometer Nuller.

Among the findings detailed in the new paper, the HOSTS scientists report that a majority of Sun-like stars in their survey do not possess high levels of dust — good news for future efforts to study potentially-habitable planets around those stars. A final report on the full HOSTS survey results is expected early next year.

More information about the new findings from HOSTS and the search for Earthlike planets beyond our solar system is available in this news release from the University of Arizona.

The LBTI is funded by NASA’s Exoplanet Exploration Program office and managed by the agency’s Jet Propulsion Laboratory in Pasadena, California. JPL is a division of Caltech, also in Pasadena. Six JPL scientists co-authored the new research paper. The LBTI is an international collaboration among institutions in the U.S., Italy and Germany, and it is managed and headquartered at the University of Arizona in Tucson.

NASA is taking a multifaceted approach to finding and studying planets outside our solar system. On April 18, NASA launched its newest planet-hunting observatory, the Transiting Exoplanet Survey Satellite (TESS), which is expected to find thousands of new exoplanets, mostly around stars smaller than our Sun.


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Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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