Members Can Post Anonymously On This Site
Astronomers Rule Out Starburst Galaxies as Contributing to the Far-Ultraviolet Background
-
Similar Topics
-
By NASA
5 min read
Astronomers Map Stellar ‘Polka Dots’ Using NASA’s TESS, Kepler
Scientists have devised a new method for mapping the spottiness of distant stars by using observations from NASA missions of orbiting planets crossing their stars’ faces. The model builds on a technique researchers have used for decades to study star spots.
By improving astronomers’ understanding of spotty stars, the new model — called StarryStarryProcess — can help discover more about planetary atmospheres and potential habitability using data from telescopes like NASA’s upcoming Pandora mission.
“Many of the models researchers use to analyze data from exoplanets, or worlds beyond our solar system, assume that stars are uniformly bright disks,” said Sabina Sagynbayeva, a graduate student at Stony Brook University in New York. “But we know just by looking at our own Sun that stars are more complicated than that. Modeling complexity can be difficult, but our approach gives astronomers an idea of how many spots a star might have, where they are located, and how bright or dark they are.”
A paper describing StarryStarryProcess, led by Sagynbayeva, published Monday, August 25, in The Astrophysical Journal.
Watch to learn how a new tool uses data from exoplanets, worlds beyond our solar system, to tell us about their polka-dotted stars.
NASA’s Goddard Space Flight Center
Download images and videos through NASA’s Scientific Visualization Studio.
NASA’s TESS (Transiting Exoplanet Survey Satellite) and now-retired Kepler Space Telescope were designed to identify planets using transits, dips in stellar brightness caused when a planet passes in front of its star.
These measurements reveal how the star’s light varies with time during each transit, and astronomers can arrange them in a plot astronomers call a light curve. Typically, a transit light curve traces a smooth sweep down as the planet starts passing in front of the star’s face. It reaches a minimum brightness when the world is fully in front of the star and then rises smoothly as the planet exits and the transit ends.
By measuring the time between transits, scientists can determine how far the planet lies from its star and estimate its surface temperature. The amount of missing light from the star during a transit can reveal the planet’s size, which can hint at its composition.
Every now and then, though, a planet’s light curve appears more complicated, with smaller dips and peaks added to the main arc. Scientists think these represent dark surface features akin to sunspots seen on our own Sun — star spots.
The Sun’s total number of sunspots varies as it goes through its 11-year solar cycle. Scientists use them to determine and predict the progress of that cycle as well as outbreaks of solar activity that could affect us here on Earth.
Similarly, star spots are cool, dark, temporary patches on a stellar surface whose sizes and numbers change over time. Their variability impacts what astronomers can learn about transiting planets.
Scientists have previously analyzed transit light curves from exoplanets and their host stars to look at the smaller dips and peaks. This helps determine the host star’s properties, such as its overall level of spottiness, inclination angle of the planet’s orbit, the tilt of the star’s spin compared to our line of sight, and other factors. Sagynbayeva’s model uses light curves that include not only transit information, but also the rotation of the star itself to provide even more detailed information about these stellar properties.
To view this video please enable JavaScript, and consider upgrading to a web browser that
supports HTML5 video
This artist’s concept illustrates the varying brightness of star with a transiting planet and several star spots. NASA’s Goddard Space Flight Center “Knowing more about the star in turn helps us learn even more about the planet, like a feedback loop,” said co-author Brett Morris, a senior software engineer at the Space Telescope Science Institute in Baltimore. “For example, at cool enough temperatures, stars can have water vapor in their atmospheres. If we want to look for water in the atmospheres of planets around those stars — a key indicator of habitability — we better be very sure that we’re not confusing the two.”
To test their model, Sagynbayeva and her team looked at transits from a planet called TOI 3884 b, located around 141 light-years away in the northern constellation Virgo.
Discovered by TESS in 2022, astronomers think the planet is a gas giant about five times bigger than Earth and 32 times its mass.
The StarryStarryProcess analysis suggests that the planet’s cool, dim star — called TOI 3384 — has concentrations of spots at its north pole, which also tips toward Earth so that the planet passes over the pole from our perspective.
Currently, the only available data sets that can be fit by Sagynbayeva’s model are in visible light, which excludes infrared observations taken by NASA’s James Webb Space Telescope. But NASA’s upcoming Pandora mission will benefit from tools like this one. Pandora, a small satellite developed through NASA’s Astrophysics Pioneers Program, will study the atmospheres of exoplanets and the activity of their host stars with long-duration multiwavelength observations. The Pandora mission’s goal is to determine how the properties of a star’s light differs when it passes through a planet’s atmosphere so scientists can better measure those atmospheres using Webb and other missions.
“The TESS satellite has discovered thousands of planets since it launched in 2018,” said Allison Youngblood, TESS project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “While Pandora will study about 20 worlds, it will advance our ability to pick out which signals come from stars and which come from planets. The more we understand the individual parts of a planetary system, the better we understand the whole — and our own.”
Facebook logo @NASAUniverse @NASAUniverse Instagram logo @NASAUniverse By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Alise Fisher
202-358-2546
alise.m.fisher@nasa.gov
NASA Headquarters, Washington
Share
Details
Last Updated Aug 25, 2025 Related Terms
Astrophysics Exoplanet Atmosphere Exoplanets Galaxies, Stars, & Black Holes Galaxies, Stars, & Black Holes Research Goddard Space Flight Center Kepler / K2 Stars TESS (Transiting Exoplanet Survey Satellite) The Universe View the full article
-
-
By European Space Agency
Astronomers have discovered a huge filament of hot gas bridging four galaxy clusters. At 10 times as massive as our galaxy, the thread could contain some of the Universe’s ‘missing’ matter, addressing a decades-long mystery.
View the full article
-
By NASA
This NASA/ESA Hubble Space Telescope image features the remote galaxy HerS 020941.1+001557, which appears as a red arc that partially encircles a foreground elliptical galaxy.ESA/Hubble & NASA, H. Nayyeri, L. Marchetti, J. Lowenthal This NASA/ESA Hubble Space Telescope image offers us the chance to see a distant galaxy now some 19.5 billion light-years from Earth (but appearing as it did around 11 billion years ago, when the galaxy was 5.5 billion light-years away and began its trek to us through expanding space). Known as HerS 020941.1+001557, this remote galaxy appears as a red arc partially encircling a foreground elliptical galaxy located some 2.7 billion light-years away. Called SDSS J020941.27+001558.4, the elliptical galaxy appears as a bright dot at the center of the image with a broad haze of stars outward from its core. A third galaxy, called SDSS J020941.23+001600.7, seems to be intersecting part of the curving, red crescent of light created by the distant galaxy.
The alignment of this trio of galaxies creates a type of gravitational lens called an Einstein ring. Gravitational lenses occur when light from a very distant object bends (or is ‘lensed’) around a massive (or ‘lensing’) object located between us and the distant lensed galaxy. When the lensed object and the lensing object align, they create an Einstein ring. Einstein rings can appear as a full or partial circle of light around the foreground lensing object, depending on how precise the alignment is. The effects of this phenomenon are much too subtle to see on a local level but can become clearly observable when dealing with curvatures of light on enormous, astronomical scales.
Gravitational lenses not only bend and distort light from distant objects but magnify it as well. Here we see light from a distant galaxy following the curve of spacetime created by the elliptical galaxy’s mass. As the distant galaxy’s light passes through the gravitational lens, it is magnified and bent into a partial ring around the foreground galaxy, creating a distinctive Einstein ring shape.
The partial Einstein ring in this image is not only beautiful, but noteworthy. A citizen scientist identified this Einstein ring as part of the SPACE WARPS project that asked citizen scientists to search for gravitational lenses in images.
Text Credit: ESA/Hubble
View the full article
-
By NASA
Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 2 min read
Hubble Images Galaxies Near and Far
This NASA/ESA Hubble Space Telescope image features the remote galaxy HerS 020941.1+001557, which appears as a red arc that partially encircles a foreground elliptical galaxy. ESA/Hubble & NASA, H. Nayyeri, L. Marchetti, J. Lowenthal This NASA/ESA Hubble Space Telescope image offers us the chance to see a distant galaxy now some 19.5 billion light-years from Earth (but appearing as it did around 11 billion years ago, when the galaxy was 5.5 billion light-years away and began its trek to us through expanding space). Known as HerS 020941.1+001557, this remote galaxy appears as a red arc partially encircling a foreground elliptical galaxy located some 2.7 billion light-years away. Called SDSS J020941.27+001558.4, the elliptical galaxy appears as a bright dot at the center of the image with a broad haze of stars outward from its core. A third galaxy, called SDSS J020941.23+001600.7, seems to be intersecting part of the curving, red crescent of light created by the distant galaxy.
The alignment of this trio of galaxies creates a type of gravitational lens called an Einstein ring. Gravitational lenses occur when light from a very distant object bends (or is ‘lensed’) around a massive (or ‘lensing’) object located between us and the distant lensed galaxy. When the lensed object and the lensing object align, they create an Einstein ring. Einstein rings can appear as a full or partial circle of light around the foreground lensing object, depending on how precise the alignment is. The effects of this phenomenon are much too subtle to see on a local level but can become clearly observable when dealing with curvatures of light on enormous, astronomical scales.
Gravitational lenses not only bend and distort light from distant objects but magnify it as well. Here we see light from a distant galaxy following the curve of spacetime created by the elliptical galaxy’s mass. As the distant galaxy’s light passes through the gravitational lens, it is magnified and bent into a partial ring around the foreground galaxy, creating a distinctive Einstein ring shape.
The partial Einstein ring in this image is not only beautiful, but noteworthy. A citizen scientist identified this Einstein ring as part of the SPACE WARPS project that asked citizen scientists to search for gravitational lenses in images.
Text Credit: ESA/Hubble
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
Share
Details
Last Updated May 20, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Hubble Space Telescope Astrophysics Astrophysics Division Galaxies Goddard Space Flight Center Gravitational Lensing Keep Exploring Discover More Topics From Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Hubble Gravitational Lenses
Focusing in on Gravitational Lenses
Hubble’s Night Sky Challenge
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.