Department in the News
Scientists seize rare chance to watch faraway star system evolve
March 4, 2020
Young stars are surrounded by dense disks of gas and dust the raw materials for creating planets. Over time, the disk scatters and disappears, making new planets visible to outside observers.
Credit: NASA/JPL-Caltech
Click on the image to enlarge, by Sherry Landow
At only 1% the age of the sun, the DS Tuc binary system shows us how a planet might naturally develop before its orbit is disturbed by external forces.

A young planet located 150 light-years away has given UNSW Sydney astrophysicists a rare chance to study a planetary system in the making.

"Finding young planets is challenging. We really need to understand the behavior of the parent star to be able to find the shallow signals of these planets which can be overwhelmed by starspots and flares," says Adina Feinstein, a National Science Foundation Graduate Research Fellow at the University of Chicago and co-author of the study.

Department students: Adina Feinstein

Leftover Big Bang light helps calculate how massive faraway galaxies are
March 3, 2020
The South Pole Telescope and Dark Energy Camera provided key data for scientists to create a new method to weigh galaxy clusters.

Photo by Daniel Michalik
Click on the image to enlarge
UChicago News
Fermilab, UChicago scientists tap South Pole Telescope data to shed light on universe

A team of scientists have demonstrated how to "weigh" galaxy clusters using light from the earliest moments of the universe - a new method that could help shed light on dark matter, dark energy and other mysteries of the cosmos, such as how the universe formed.

The new method calculates the bending of light around galaxy clusters using the orientation of light from shortly after the Big Bang - data taken by the South Pole Telescope and the Dark Energy Camera.

"Gravitational lensing," a phenomenon in which light distorts as it's affected by the gravity of big objects like galaxies, can function as a kind of magnifying glass. It's helped scientists discover key information about the universe - but it's always been done by looking for the smearing of light around distant objects like stars.

In a study published in Physical Review Letters, Fermilab and University of Chicago scientist Brad Benson and colleagues use a different method to calculate the masses of distant galaxies: the polarization, or orientation, of the light left over from the moments after the Big Bang.

"Making this estimate is important because most of the mass of galaxy clusters isn't even visible - it's dark matter, which does not emit light but interacts through gravity and makes up about 85% of the matter in our universe," said Benson, an assistant professor in the Department of Astronomy and Astrophysics. "Since photons from the cosmic microwave background have literally traveled across the entire observable universe, this method has the potential to more accurately measure the dark matter mass in the most distant galaxy clusters."

Department members: Bradford A. Benson, John E. Carlstrom
Scientific projects: South Pole Telescope

New Solar Telescope Reveals Sun's Surface in More Detail than Ever Before
February 13, 2020
WTTW News, by Paul Caine
A new solar telescope in Hawaii has captured images of the sun unlike any seen before. Professor Robert Rosner, an astrophysicist at the University of Chicago and one of the lead investigators on the project, says he's been waiting for almost 40 years to see images like the ones recently captured.
"Those of us fascinated by the sun - and who would not be? - have been waiting since the 1980s to see the sun at high resolution, to see if the amazing structuring of the surface, from the grand sunspots down to the 'salt and pepper' smaller magnetic structure, continues to yet smaller spatial scales. And it does!" said Rosner. "The physics to be mined from this result, these remarkable images, are just so exciting."

Department members: Robert Rosner

Prof. Eugene Parker wins prestigious Crafoord Prize in Astronomy
January 31, 2020
Prof. Emeritus Eugene Parker, 92, laid the foundations for a new field of astrophysics with his research on stars and magnetic fields.
Photo by Jean Lachat
Click on the image to enlarge
UChicago News, by Louise Lerner
Swedish Royal Academy of Sciences honors UChicago scientist's pioneering work.

The Royal Swedish Academy of Sciences announced Jan. 30 that University of Chicago Prof. Emeritus Eugene Parker has been awarded the 2020 Crafoord Prize in Astronomy.

Awarded every three years, the prestigious Crafoord Prize consists of a gold medal and a sum of six million Swedish krona (about $600,000) - one of the largest prizes in science.

The Academy, which is also responsible for selecting Nobel Prize winners, cited Parker for his "pioneering and fundamental studies of the solar wind and magnetic fields from stellar to galactic scales."

Parker is widely known for his proposal of the solar wind, which radically changed scientists' understanding of the solar system. He suggested, and spacecraft later confirmed, that the sun radiates an intense stream of charged particles that travel throughout the solar system at supersonic speeds. The discovery reshaped our view of space, stars and their surroundings, and it laid the foundations for a new field of astrophysics.

"I am humbled by the award of the Crafoord Prize," said Parker, now 92. "It gives strong incentive for maintaining the historic high level of research that merits the prize."

Department members: Eugene N. Parker

NASA's TESS spacecraft discovers its first habitable planet, first world with two stars
January 9, 2020
An illustration of what the climate of the newly discovered exoplanet TOI 700 d might look like.
Illustration courtesy NASA Goddard Space Flight Center/Chris Smith (USRA)
Click on the image to enlarge
UChicago News
Teams including UChicago scientists analyze Earth-size world and Tatooine-like planet

Scientists from the University of Chicago --- Emily Gilbert, Adina Feinstein, Daniel Fabrycky and Benjamin Montet --- and other institutions around the world have discovered multiple new interesting worlds beyond Earth --- including its first potentially habitable Earth-size world and another that is a 'Star Wars'-type system with two suns.

The new exoplanets --- planets beyond our solar system - were spotted with NASA's new TESS satellite and announced Jan. 6 at the 235th American Astronomical Society meeting. In both cases, high school students helped find them.

Department members: Daniel Fabrycky, Benjamin Montet
Department students: Adina Feinstein, Emily Gilbert

What will the next decade bring in science?
January 2, 2020
NASA, ESA, the Hubble Heritage Team (STScI/AURA) and J. Green (University of Colorado, Boulder)
Click on the image to enlarge
UChicago News
Daniel Holz, astrophysicist

What do you think might be the most exciting result of scientific or technological advances in the next decade?

Our gravitational wave detectors are getting more and more sensitive, so we'll learn a ton about the universe as we get more data. Then there's a few roll-of-the-dice things that could happen that would be amazing. Like if a supernova went off in our own galaxy --- with all the ways we have to detect astronomical events now, that would be an incredible way to learn about everything from the physics of stars to the history of the universe. Those happen about once every hundred years, so it could be anytime. Or maybe something unusual will pop up in our gravitational wave detectors --- we've picked up black hole collisions and neutron star collisions, but what if we detected waves from cosmic strings?

The most exciting thing is always something you haven't anticipated. In astronomy, whenever we've invented a new way to look at the sky, we discover something new that no one had ever thought of before. Our gravitational wave detectors haven't discovered anything profoundly unexpected, at least not yet.

What's a possible consequence of science or technology in the next decade that you worry about?

Two things that worry me about the future are nuclear annihilation and climate change --- both due to technological advancements. I'm a member of the Bulletin of the Atomic Scientists, which sets the Doomsday Clock, so that's something we think about a lot.

The next 10 years will be critical for climate. We can impact just how bad things will get decades from now. If we act now, we might avoid some of the worst, civilization-threatening outcomes. The danger of nuclear annihilation is on the rise, too. These are compounded by the deliberate erosion of facts and truth, which pose grave threats to society.

The number of ways in which we walk blithely into Armageddon is very high. But that's something all of us can help address. Agitate for change! It's not too late.

Department members: Daniel E. Holz
Scientific projects: Laser Interferometer Gravitational-wave Observatory

Parker Solar Probes first discoveries: Odd phenomena in space weather, solar wind
December 5, 2019
Prof. Emeritus Eugene Parker
UChicago News
NASA mission named for pioneering UChicago scientist produces landmark research

Last summer, NASA's Parker Solar Probe split the predawn skies in a blaze of light as it headed closer to the sun than any other spacecraft. Named for pioneering University of Chicago astrophysicist Eugene Parker, the probe has now made three of its 24 planned passes through the sun's corona - enough for scientists to announce their first discoveries.

In four papers published Dec. 4 in Nature, researchers describe strange space phenomena and a flood of new data that will help us understand everything from the nature of stars to improving our forecasting of solar storms that can affect electronics on Earth.

Sidling up to the nearest star that humans can reach, the Parker Solar Probe learned new information about two types of major space weather events. It also saw the first signs of the zone around the sun where cosmic dust disappears - predicted decades ago, but never seen - as well as an entirely new phenomenon: bizarre "switchbacks" in the solar wind that flows off the surface of the sun. Scientists said it will dramatically change our theories of the corona and solar wind.

Scientists are eager to learn more about the the solar wind - a flow of charged particles off the surface of the sun which radically affects the Earth and the entire solar system, which University of Chicago Professor Emeritus Eugene Parker first proposed in 1958. NASA named the solar mission after the famed astrophysicist in 2017.

Department members: Eugene N. Parker

Astronomers Propose a Novel Method of Finding Atmospheres on Rocky Worlds
December 2, 2019
This artist's impression shows a rocky exoplanet with a wispy, cloudy atmosphere orbiting a red dwarf star. Astronomers have identified a new method that could allow Webb to detect an exoplanet's atmosphere in just a few hours of observing time.
Credits: L. Hustak and J. Olmsted (STScI)
Click on the image to enlarge
When NASA's James Webb Space Telescope launches in 2021, one of its most anticipated contributions to astronomy will be the study of exoplanets - planets orbiting distant stars. Among the most pressing questions in exoplanet science is: Can a small, rocky exoplanet orbiting close to a red dwarf star hold onto an atmosphere?

In a series of four papers in the Astrophysical Journal, a team of astronomers proposes a new method of using Webb to determine whether a rocky exoplanet has an atmosphere. The technique, which involves measuring the planet's temperature as it passes behind its star and then comes back into view, is significantly faster than more traditional methods of atmospheric detection like transmission spectroscopy.

"We find that Webb could easily infer the presence or absence of an atmosphere around a dozen known rocky exoplanets with less than 10 hours of observing time per planet," said Jacob Bean of the University of Chicago, a co-author on three of the papers.

Astronomers are particularly interested in exoplanets orbiting red dwarf stars for a number of reasons. These stars, which are smaller and cooler than the Sun, are the most common type of star in our galaxy. Also, because a red dwarf is small, a planet passing in front of it will appear to block a larger fraction of the star's light than if the star were larger, like our Sun. This makes the planet orbiting a red dwarf easier to detect through this "transit" technique.

Red dwarfs also produce a lot less heat than our Sun, so to enjoy habitable temperatures, a planet would need to orbit quite close to a red dwarf star. In fact, to be in the habitable zone - the area around the star where liquid water could exist on a planet's surface - the planet has to orbit much closer to the star than Mercury is to the Sun. As a result, it will transit the star more frequently, making repeated observations easier.

But a planet orbiting so close to a red dwarf is subjected to harsh conditions. Young red dwarfs are very active, blasting out huge flares and plasma eruptions. The star also emits a strong wind of charged particles. All of these effects could potentially scour away a planet's atmosphere, leaving behind a bare rock.

"Atmospheric loss is the number one existential threat to the habitability of planets," said Bean.

Department members: Jacob L. Bean

NASA Instrument to Probe Planet Clouds on European Mission
November 11, 2019
Click on the image to enlarge
NASA will contribute an instrument to a European space mission that will explore the atmospheres of hundreds of planets orbiting stars beyond our Sun, or exoplanets, for the first time.

The instrument, called the Contribution to ARIEL Spectroscopy of Exoplanets, or CASE, adds scientific capabilities to ESA's (the European Space Agency's) Atmospheric Remote-sensing Infrared Exoplanet Large-survey, or ARIEL, mission.

Prof. Jacob Bean is the science team lead for the new CASE mission.

Department members: Jacob L. Bean

Fermilab and University of Chicago scientist Josh Frieman awarded $1 million by DOE Office of Science
October 18, 2019
Josh Frieman
Photo: Brandon Schulman
Fermilab, by Leah Hesla
The Department of Energy has awarded Fermilab and University of Chicago scientist Josh Frieman $1 million over three years as part of the inaugural Office of Science Distinguished Scientist Fellowship program.

Office of Science distinguished scientist fellows were chosen from nominations submitted by nine U.S. national laboratories. Frieman is one of only five scientists selected, chosen for his scientific leadership, engagement with the academic research community, scientific excellence and significant scientific achievement.

The Distinguished Scientist Fellowship was established to develop, sustain and promote excellence in Office of Science research through collaborations between institutions of higher education and national laboratories.

Frieman says he will use the funding to support his cosmic research program and to foster tighter connections in cosmic frontier research between Fermilab and the University of Chicago.

Department members: Joshua A. Frieman

Nearly a decade in the making, exoplanet-hunting instrument installed in Hawaii
October 2, 2019
MAROON-X team members and Gemini Observatory staff standing in front of the Gemini North telescope with the MAROON-X unit. (From left): Paul McBride, John Randrup, Rody Kawaihae, Harlan Uehara, and Eduardo Tapia of Gemini Observatory; MAROON-X team members Andreas Seifahrt, David Kasper and Julian Stuermer; as well as Alison Peck, and John White of Gemini Observatory.
Image courtesy of Andreas Seifahrt
Click on the image to enlarge
UChicago News, by Louise Lerner
Built by UChicago scientists, MAROON-X will search for worlds in other solar systems

Atop a dormant volcano in Hawaii, an extremely delicate instrument - designed to help scientists find distant worlds - is scattered across the floor in hundreds of pieces.

"Imagine trying to assemble one of those huge LEGO sets, except there's no instruction book; you've done it once before, but then you had to take it all apart and put it in little bags," said Jacob Bean, associate professor of astronomy and astrophysics at the University of Chicago. "Also you're at 14,000 feet, and when the air is that thin it impairs your judgment and thinking, and so here you are working 12-hour shifts lifting heavy things but also trying to put together a delicate instrument."

This was Bean's task as the head of a UChicago project to build and install an innovative instrument that will scan the skies for new exoplanets - worlds in other solar systems that could potentially host life. Over the past eight years, Bean and his team had designed and built the instrument, called MAROON-X; this summer they finally attached it to a telescope at the Gemini Observatory at the top of Mauna Kea, Hawaii.

"It has been a pretty intense six months for my team to commission this instrument," said Bean, an expert in faraway worlds whose research focuses on discovering and examining potentially habitable planets in other solar systems. "But in the next 10 years we're going to learn things about habitable worlds that we'd never known before. It's going to be really transformative."

However, we still have no confirmed Earth - like exoplanets with habitable surface conditions. The thing about Earth-like planets, which is why it is taking so long to be able to find and characterize them, is that they're extremely hard to see. Because these planets are circling around a star that is at least a million times brighter than they are, trying to look directly for them is like trying to see a lightning bug next to a lighthouse that is on the other side of the country. So scientists have to find indirect ways of finding them based on the effects they have on their stars.

MAROON-X does this by noticing the extremely tiny gravitational tug that an exoplanet (or two, or five, or seven) exerts on its star as it orbits around it. This tug causes the star to wobble just the slightest bit in its orbit. But that's enough motion to catch it.

Attached to the Gemini North telescope, MAROON-X takes all the light gathered by the 25-foot telescope and focuses it down to a spot that is the width of a human hair. Then it separates out that light into the different colors of the rainbow and reads the intensity of each band. The color of the light will change slightly as the star moves forward or back. "It's kind of like a radar gun for stars," Bean said.

Several decades ago, advances in technology allowed scientists to begin detecting the very faint signatures from planets orbiting other stars in faraway solar systems. There's been an explosion of discoveries; currently, NASA lists 4,000 confirmed exoplanets and thousands more candidates.

Department members: Jacob L. Bean, David Kasper, Andreas Seifahrt, Julian Stuermer
Scientific projects: MAROON-X: M dwarf Advanced Radial velocity Observer Of Neighboring eXoplanets

Ambitious project to map the Big Bang's afterglow earns NSF funding
September 30, 2019
The UChicago-led South Pole Telescope maps the leftover light from the earliest age of the universe.
Photo by Jason Gallicchio
Click on the image to enlarge
UChicago News, by Louise Lerner
UChicago-led proposal receives NSF funding for pioneering sky measurements

The National Science Foundation has awarded $4 million to the University of Chicago to host the development of an ambitious multi-institutional program to map the leftover light from the Big Bang in greater detail than ever before.

Called CMB-S4, the groundbreaking project will allow us to see back in time to the earliest epoch of the universe. Remnant light from this period, called the cosmic microwave background, is still visible in the skies and holds clues to many of the most pressing mysteries about the universe - from its earliest moments to how it evolved to produce the wondrous structure of galaxies, stars and planets that we see today.

"The history of the universe-and the physics that govern its evolution - are encoded in the cosmic microwave background, and rigorous, precise measurements will allows us to unlock this information and will likely lead to new discoveries," said renowned UChicago cosmologist John Carlstrom, principal investigator for this initial phase of the project and co-spokesperson of the CMB-S4 collaboration, who also holds a joint appointment at Argonne National Laboratory. "These are big, big topics in physics, many of which we don't know how to get at any other way."

The CMB-S4 project builds on the success of pioneering observations of the cosmic microwave background from telescopes located in the high Chilean Atacama plateau and at the South Pole, including the 10-meter diameter South Pole Telescope - an international collaboration led by Carlstrom for more than a decade.

But the next phase, which is projected to see first light in the late 2020s, will provide much more sensitivity - requiring new telescopes working in concert, as well as a much larger science team.

The new CMB-S4 telescopes will be deployed to the South Pole and to the Atacama Desert in Chile - two places whose cold, dry climates offer the best sky viewing on Earth. They will allow CMB-S4 to boost the precision of its map by more than an order of magnitude past the best readings we have today.

The initial $4 million from the National Science Foundation will complement funding from the U.S. Department of Energy to support the design of the project. CMB-S4 will be a massive, multi-institutional effort over the next decade, with a total cost of the order of half a billion dollars. The project will involve multiple universities as well as the Department of Energy's national laboratories. The CMB-S4 collaboration consists of 200 scientists from over 70 institutions spread across 12 countries.

This incredible precision will enable physicists to look for evidence of ancient gravitational waves - ripples in the fabric of space-time created by the Big Bang - as well as insights into the elusive question of how to tie the force of gravity and the theory of quantum mechanics together. It also may provide fodder for the search for dark matter, a mysterious substance that pervades the universe, but has yet to be detected directly.

Astronomers will also find a trove of information about stars, galaxies and clusters in the CMB-S4 data - for example, cosmic microwave background observations from the South Pole Telescope and the Chilean Atacama Cosmology Telescope have made numerous discoveries, including record-breaking massive clusters of galaxies and ancient stellar nurseries.

"The history of the universe - and the physics that govern its evolution - are encoded in the cosmic microwave background."
-Prof. John Carlstrom

The University of Chicago has a long history of working at the Amundsen-Scott South Pole Station, which is managed by the National Science Foundation. The design team will also work with Associated University, Inc., which will coordinate the CMB-S4 plans for Chile.

"We've learned an incredible amount from measurements of the cosmic microwave background, including discoveries that have pointed the way to new physics, but we have really only begun to tap the information that's encoded there," said CMB-S4 co-spokesperson Julian Borrill from DOE's Lawrence Berkeley National Laboratory. "This will be a major leap forward for the entire physics and astronomy community."

The award is being made from a new NSF program for Mid-scale Research Infrastructure. "These awards represent the first in NSF's agency-wide effort to support the mid-range infrastructure that will be invaluable to strengthening the U.S. scientific research enterprise," said Jim Ulvestad, the National Science Foundation's chief officer for research facilities. "The funded projects include an impressive collection of new design efforts and advanced instrumentation. These projects fill gaps and provide unique research capabilities for the U.S. that will engage many early-career scientists and engineers in the pursuit of groundbreaking discoveries."

Department members: John E. Carlstrom
Scientific projects: Cosmic Microwave Background Stage 4, South Pole Telescope