Members Can Post Anonymously On This Site
-
Similar Topics
-
By NASA
5 min read
Ultra-low-noise Infrared Detectors for Exoplanet Imaging
A linear-mode avalanche photodiode array in the test dewar. The detector is the dark square in the center. Michael Bottom, University of Hawai’i One of the ultimate goals in astrophysics is the discovery of Earth-like planets that are capable of hosting life. While thousands of planets have been discovered around other stars, the vast majority of these detections have been made via indirect methods, that is, by detecting the effect of the planet on the star’s light, rather than detecting the planet’s light directly. For example, when a planet passes in front of its host star, the brightness of the star decreases slightly.
However, indirect methods do not allow for characterization of the planet itself, including its temperature, pressure, gravity, and atmospheric composition. Planetary atmospheres may include “biosignature” gases like oxygen, water vapor, carbon dioxide, etc., which are known to be key ingredients needed to support life as we know it. As such, direct imaging of a planet and characterization of its atmosphere are key to understanding its potential habitability.
But the technical challenges involved in imaging Earth-like extrasolar planets are extreme. First such planets are detected only by observing light they reflect from their parent star, and so they typically appear fainter than the stars they orbit by factors of about 10 billion. Furthermore, at the cosmic distances involved, the planets appear right next to the stars. A popular expression is that exoplanet imaging is like trying to detect a firefly three feet from a searchlight from a distance of 300 miles.
Tremendous effort has gone into developing starlight suppression technologies to block the bright glare of the star, but detecting the light of the planet is challenging in its own right, as planets are incredibly faint. One way to quantify the faintness of planetary light is to understand the photon flux rate. A photon is an indivisible particle of light, that is, the minimum detectable amount of light. On a sunny day, approximately 10 thousand trillion photons enter your eye every second. The rate of photons entering your eye from an Earth-like exoplanet around a nearby star would be around 10 to 100 per year. Telescopes with large mirrors can help collect as much of this light as possible, but ultra-sensitive detectors are also needed, particularly for infrared light, where the biosignature gases have their strongest effects. Unfortunately, state-of-the-art infrared detectors are far too noisy to detect the low level of light emitted from exoplanets.
With support from NASA’s Astrophysics Division and industrial partners, researchers at the University of Hawai’i are developing a promising detector technology to meet these stringent sensitivity requirements. These detectors, known as avalanche photodiode arrays, are constructed out of the same semiconductor material as conventional infrared sensors. However, these new sensors employ an extra “avalanche” layer that takes the signal from a single photon and multiplies it, much like an avalanche can start with a single snowball and quickly grow it to the size of a boulder. This signal amplification occurs before any noise from the detector is introduced, so the effective noise is proportionally reduced. However, at high avalanche levels, photodiodes start to behave badly, with noise exponentially increasing, which negates any benefits of the signal amplification. Late University of Hawai’i faculty member Donald Hall, who was a key figure in driving technology for infrared astronomy, realized the potential use of avalanche photodiodes for ultra-low-noise infrared astronomy with some modifications to the material properties.
University of Hawai’i team members with cryogenic dewar used to test the sensors. From left to right, Angelu Ramos, Michael Bottom, Shane Jacobson, Charles-Antoine Claveau. Michael Bottom, University of Hawai’i The most recent sensors benefit from a new design including a graded semiconductor bandgap that allows for excellent noise performance at moderate amplification, a mesa pixel geometry to reduce electronic crosstalk, and a read-out integrated circuit to allow for short readout times. “It was actually challenging figuring out just how sensitive these detectors are,” said Michael Bottom, associate professor at the University of Hawai’i and lead of development effort. “Our ‘light-tight’ test chamber, which was designed to evaluate the infrared sensors on the James Webb Space Telescope, was supposed to be completely dark. But when we put these avalanche photodiodes in the chamber, we started seeing light leaks at the level of a photon an hour, which you would never be able to detect using the previous generation of sensors.”
The new designs have a format of one megapixel, more than ten times larger than the previous iteration of sensors, and circuitry that allows for tracking and subtracting any electronic drifts. Additionally, the pixel size and control electronics are such that these new sensors could be drop-in replacements for the most common infrared sensors used on the ground, which would give new capabilities to existing instruments.
Image of the Palomar-2 globular cluster located in the constellation of Auriga, taken with the linear-mode avalanche photodiode arrays, taken from the first on-sky testing of the sensors using the University of Hawai’i’s 2.2 meter telescope. Michael Bottom, University of Hawai’i Last year, the team took the first on-sky images from the detectors, using the University of Hawai’i’s 2.2-meter telescope. “It was impressive to see the avalanche process on sky. When we turned up the gain, we could see more stars appear,” said Guillaume Huber, a graduate student working on the project. “The on-sky demonstration was important to prove the detectors could perform well in an operational environment,” added Michael Bottom.
According to the research team, while the current sensors are a major step forward, the megapixel format is still too small for many science applications, particularly those involving spectroscopy. Further tasks include improving detector uniformity and decreasing persistence. The next generation of sensors will be four times larger, meeting the size requirements for the Habitable Worlds Observatory, NASA’s next envisioned flagship mission, with the goals of imaging and characterizing Earth-like exoplanets.
Project Lead: Dr. Michael Bottom, University of Hawai’i
Sponsoring Organization: NASA Strategic Astrophysics Technology (SAT) Program
Share
Details
Last Updated Feb 18, 2025 Related Terms
Technology Highlights Astrophysics Astrophysics Division Science-enabling Technology Explore More
6 min read Webb Reveals Rapid-Fire Light Show From Milky Way’s Central Black Hole
Article
5 mins ago
2 min read Hubble Captures a Cosmic Cloudscape
Article
4 days ago
5 min read Webb Maps Full Picture of How Phoenix Galaxy Cluster Forms Stars
Article
5 days ago
View the full article
-
By NASA
NASA’s SpaceX Crew-10 members (from left to right) Roscosmos cosmonaut Kirill Peskov, NASA astronauts Nichole Ayers and Anne McClain, and JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi pictured training at SpaceX in Hawthorne, California.Credit: SpaceX Media accreditation is open for the launch of NASA’s 10th rotational mission of a SpaceX Falcon 9 rocket and Dragon spacecraft, carrying astronauts to the International Space Station for a science expedition. The agency’s SpaceX Crew-10 mission is targeting launch on Wednesday, March 12, from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.
The launch will carry NASA astronauts Anne McClain as commander and Nichole Ayers as pilot, along with JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi and Roscosmos cosmonaut Kirill Peskov as mission specialists. This is the first spaceflight for Ayers and Peskov, and the second mission to the orbiting laboratory for McClain and Onishi.
Media accreditation deadlines for the Crew-10 launch as part of NASA’s Commercial Crew Program are as follows:
International media without U.S. citizenship must apply by 11:59 p.m. on Thursday, Feb. 13. U.S. media and U.S. citizens representing international media organizations must apply by 11:59 p.m. EST on Sunday, Feb. 23. All accreditation requests must be submitted online at:
https://media.ksc.nasa.gov
NASA’s media accreditation policy is online. For questions about accreditation or special logistical requests, email: ksc-media-accreditat@mail.nasa.gov. Requests for space for satellite trucks, tents, or electrical connections are due by Friday, Feb. 21.
For other questions, please contact NASA Kennedy’s newsroom at: 321-867-2468.
Para obtener información sobre cobertura en español en el Centro Espacial Kennedy o si desea solicitar entrevistas en español, comuníquese con Antonia Jaramillo: 321-501-8425, o Messod Bendayan: 256-930-1371.
For launch coverage and more information about the mission, visit:
https://www.nasa.gov/commercialcrew
-end-
Joshua Finch / Claire O’Shea
Headquarters, Washington
202-358-1100
joshua.a.finch@nasa.gov / claire.a.o’shea@nasa.gov
Steve Siceloff / Stephanie Plucinsky
Kennedy Space Center, Florida
321-867-2468
steven.p.siceloff@nasa.gov / stephanie.n.plucinsky@nasa.gov
Kenna Pell
Johnson Space Center, Houston
281-483-5111
kenna.m.pell@nasa.gov
Share
Details
Last Updated Feb 11, 2025 EditorJessica TaveauLocationNASA Headquarters Related Terms
Humans in Space Commercial Crew Commercial Space International Space Station (ISS) Johnson Space Center Kennedy Space Center Space Operations Mission Directorate View the full article
-
By NASA
NASA astronauts Don Pettit and Nick Hague are at the controls of the robotics workstation.
Credit: NASA
Students from Rocky Hill, Connecticut, will have the chance to connect with NASA astronauts Nick Hague and Don Pettit as they answer prerecorded science, technology, engineering, and mathematics-related questions from aboard the International Space Station.
Watch the 20-minute space-to-Earth call at 11:40 a.m. EST on Tuesday, Feb. 18, on NASA+ and learn how to watch NASA content on various platforms, including social media.
The event for kindergarten through 12th grade students will be hosted at Rocky Hill Library in Rocky Hill, near Hartford, Connecticut. The goal is to engage area students by introducing them to the wide variety of STEM career opportunities available in space exploration and related fields.
Media interested in covering the event must contact by 5 p.m., Thursday, Feb. 14, to Gina Marie Davies at: gdavies@rockyhillct.gov or 860-258-2530.
For more than 24 years, astronauts have continuously lived and worked aboard the space station, testing technologies, performing science, and developing skills needed to explore farther from Earth. Astronauts aboard the orbiting laboratory communicate with NASA’s Mission Control Center in Houston 24 hours a day through SCaN’s (Space Communications and Navigation) Near Space Network.
Important research and technology investigations taking place aboard the space station benefit people on Earth and lay the groundwork for other agency missions. As part of NASA’s Artemis campaign, the agency will send astronauts to the Moon to prepare for future human exploration of Mars; inspiring Artemis Generation explorers and ensuring the United States continues to lead in space exploration and discovery.
See videos and lesson plans highlighting space station research at:
https://www.nasa.gov/stemonstation
-end-
Abbey Donaldson
Headquarters, Washington
202-358-1600
Abbey.a.donaldson@nasa.gov
Sandra Jones
Johnson Space Center, Houston
281-483-5111
sandra.p.jones@nasa.gov
Share
Details
Last Updated Feb 11, 2025 LocationNASA Headquarters Related Terms
Humans in Space Astronauts International Space Station (ISS) Space Communications & Navigation Program View the full article
-
By NASA
This artist’s concept visualizes a super-Neptune world orbiting a low-mass star near the center of our Milky Way galaxy. Scientists recently discovered such a system that may break the current record for fastest exoplanet system, traveling at least 1.2 million miles per hour, or 540 kilometers per second.NASA/JPL-Caltech/R. Hurt (Caltech-IPAC) Astronomers may have discovered a scrawny star bolting through the middle of our galaxy with a planet in tow. If confirmed, the pair sets a new record for the fastest-moving exoplanet system, nearly double our solar system’s speed through the Milky Way.
The planetary system is thought to move at least 1.2 million miles per hour, or 540 kilometers per second.
“We think this is a so-called super-Neptune world orbiting a low-mass star at a distance that would lie between the orbits of Venus and Earth if it were in our solar system,” said Sean Terry, a postdoctoral researcher at the University of Maryland, College Park and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Since the star is so feeble, that’s well outside its habitable zone. “If so, it will be the first planet ever found orbiting a hypervelocity star.”
A paper describing the results, led by Terry, was published in The Astronomical Journal on February 10.
A Star on the Move
The pair of objects was first spotted indirectly in 2011 thanks to a chance alignment. A team of scientists combed through archived data from MOA (Microlensing Observations in Astrophysics) – a collaborative project focused on a microlensing survey conducted using the University of Canterbury Mount John Observatory in New Zealand — in search of light signals that betray the presence of exoplanets, or planets outside our solar system.
Microlensing occurs because the presence of mass warps the fabric of space-time. Any time an intervening object appears to drift near a background star, light from the star curves as it travels through the warped space-time around the nearer object. If the alignment is especially close, the warping around the object can act like a natural lens, amplifying the background star’s light.
This artist’s concept visualizes stars near the center of our Milky Way galaxy. Each has a colorful trail indicating its speed –– the longer and redder the trail, the faster the star is moving. NASA scientists recently discovered a candidate for a particularly speedy star, visualized near the center of this image, with an orbiting planet. If confirmed, the pair sets a record for fastest known exoplanet system.NASA/JPL-Caltech/R. Hurt (Caltech-IPAC) In this case, microlensing signals revealed a pair of celestial bodies. Scientists determined their relative masses (one is about 2,300 times heavier than the other), but their exact masses depend on how far away they are from Earth. It’s sort of like how the magnification changes if you hold a magnifying glass over a page and move it up and down.
“Determining the mass ratio is easy,” said David Bennett, a senior research scientist at the University of Maryland, College Park and NASA Goddard, who co-authored the new paper and led the original study in 2011. “It’s much more difficult to calculate their actual masses.”
The 2011 discovery team suspected the microlensed objects were either a star about 20 percent as massive as our Sun and a planet roughly 29 times heavier than Earth, or a nearer “rogue” planet about four times Jupiter’s mass with a moon smaller than Earth.
To figure out which explanation is more likely, astronomers searched through data from the Keck Observatory in Hawaii and ESA’s (European Space Agency’s) Gaia satellite. If the pair were a rogue planet and moon, they’d be effectively invisible – dark objects lost in the inky void of space. But scientists might be able to identify the star if the alternative explanation were correct (though the orbiting planet would be much too faint to see).
They found a strong suspect located about 24,000 light-years away, putting it within the Milky Way’s galactic bulge — the central hub where stars are more densely packed. By comparing the star’s location in 2011 and 2021, the team calculated its high speed.
This Hubble Space Telescope image shows a bow shock around a very young star called LL Ori. Named for the crescent-shaped wave made by a ship as it moves through water, a bow shock can be created in space when two streams of gas collide. Scientists think a similar feature may be present around a newfound star that could be traveling at least 1.2 million miles per hour, or 540 kilometers per second. Traveling at such a high velocity in the galactic bulge (the central part of the galaxy) where gas is denser could generate a bow shock. NASA and The Hubble Heritage Team (STScI/AURA); Acknowledgment: C. R. O’Dell (Vanderbilt University) But that’s just its 2D motion; if it’s also moving toward or away from us, it must be moving even faster. Its true speed may even be high enough to exceed the galaxy’s escape velocity of just over 1.3 million miles per hour, or about 600 kilometers per second. If so, the planetary system is destined to traverse intergalactic space many millions of years in the future.
“To be certain the newly identified star is part of the system that caused the 2011 signal, we’d like to look again in another year and see if it moves the right amount and in the right direction to confirm it came from the point where we detected the signal,” Bennett said.
“If high-resolution observations show that the star just stays in the same position, then we can tell for sure that it is not part of the system that caused the signal,” said Aparna Bhattacharya, a research scientist at the University of Maryland, College Park and NASA Goddard who co-authored the new paper. “That would mean the rogue planet and exomoon model is favored.”
NASA’s upcoming Nancy Grace Roman Space Telescope will help us find out how common planets are around such speedy stars, and may offer clues to how these systems are accelerated. The mission will conduct a survey of the galactic bulge, pairing a large view of space with crisp resolution.
“In this case we used MOA for its broad field of view and then followed up with Keck and Gaia for their sharper resolution, but thanks to Roman’s powerful view and planned survey strategy, we won’t need to rely on additional telescopes,” Terry said. “Roman will do it all.”
Download additional images and video from NASA’s Scientific Visualization Studio.
By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, Md.
301-286-1940
Share
Details
Last Updated Feb 10, 2025 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationGoddard Space Flight Center Related Terms
Exoplanets Astrophysics Exoplanet Discoveries Exoplanet Science Goddard Space Flight Center Nancy Grace Roman Space Telescope Neptune-Like Exoplanets Science & Research Studying Exoplanets The Universe Explore More
4 min read Discovery Alert: With Six New Worlds, 5,500 Discovery Milestone Passed!
On Aug. 24, 2023, more than three decades after the first confirmation of planets beyond…
Article 7 months ago 3 min read Discovery Alert: Water Vapor Detected on a ‘Super Neptune’
The atmosphere of a “super Neptune” some 150 light-years distant contains water vapor, a new…
Article 3 years ago 6 min read Why NASA’s Roman Mission Will Study Milky Way’s Flickering Lights
Article 1 year ago
View the full article
-
By NASA
NASA/Joel Kowsky An adult Alamosaurus sports eclipse glasses outside of The Children’s Museum of Indianapolis, on April 6, 2024. Two days later, the total solar eclipse swept across a narrow portion of the North American continent from Mexico’s Pacific coast to the Atlantic coast of Newfoundland, Canada. A partial solar eclipse was visible across the entire North American continent along with parts of Central America and Europe.
The NASA Headquarters photo team chose this image as one of the best from 2024. See more of the top 100 from last year on Flickr.
Image credit: NASA/Joel Kowsky
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.