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NASA’S JWST measures the temperature of a rocky exoplanet

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An international team of researchers has used the NASA/ESA/CSA James Webb Space Telescope to measure the temperature of the rocky exoplanet TRAPPIST-1 b. The measurement is based on the planet’s thermal emission: heat energy given off in the form of infrared light detected by Webb’s Mid-Infrared Instrument (MIRI). The result indicates that the planet’s dayside has a temperature of about 500 kelvins (roughly 230°C), and suggests that it has no significant atmosphere. This is the first detection of any form of light emitted by an exoplanet as small and as cool as the rocky planets in our own solar system. The result marks an important step in determining whether planets orbiting small active stars like TRAPPIST-1 can sustain atmospheres needed to support life. It also bodes well for Webb’s ability to characterise temperate, Earth-sized exoplanets using MIRI.

“These observations really take advantage of Webb’s mid-infrared capability,” said Thomas Greene, an astrophysicist at NASA’s Ames Research Center and lead author on the study published today in the journal Nature. “No previous telescopes have had the sensitivity to measure such dim mid-infrared light.”

Rocky planets orbiting ultra cool red dwarfs

In early 2017, astronomers reported the discovery of seven rocky planets orbiting an ultracool red dwarf star (or M dwarf) 40 light-years from Earth. What is remarkable about the planets is their similarity in size and mass to the inner, rocky planets of our own solar system. Although they all orbit much closer to their star than any of our planets orbit the Sun – all could fit comfortably within the orbit of Mercury – they receive comparable amounts of energy from their tiny star.

TRAPPIST-1 b, the innermost planet, has an orbital distance about one hundredth that of Earth’s and receives about four times the amount of energy that Earth gets from the Sun. Although it is not within the system’s habitable zone, observations of the planet can provide important information about its sibling planets, as well as those of other M-dwarf systems.

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“There are ten times as many of these stars in the Milky Way as there are stars like the Sun, and they are twice as likely to have rocky planets as stars like the Sun,” explained Greene. “But they are also very active – they are very bright when they’re young and they give off flares and X-rays that can wipe out an atmosphere.”

Co-author Elsa Ducrot from CEA in France, who was on the team that conducted the initial studies of the TRAPPIST-1 system, added, “It’s easier to characterise terrestrial planets around smaller, cooler stars. If we want to understand habitability around M stars, the TRAPPIST-1 system is a great laboratory. These are the best targets we have for looking at the atmospheres of rocky planets.”

Detecting an atmosphere (or not)

Previous observations of TRAPPIST-1 b with the NASA/ESA Hubble Space Telescope, as well as NASA’s Spitzer Space Telescope, found no evidence for a puffy atmosphere, but were not able to rule out a dense one.

One way to reduce the uncertainty is to measure the planet’s temperature. “This planet is tidally locked, with one side facing the star at all times and the other in permanent darkness,” said Pierre-Olivier Lagage from CEA, a co-author on the paper. “If it has an atmosphere to circulate and redistribute the heat, the dayside will be cooler than if there is no atmosphere.”

Light curve showing the change in brightness of the TRAPPIST-1 system as the innermost planet, TRAPPIST-1 b, moves behind the star. This phenomenon is known as a secondary eclipse.Astronomers used Webb’s Mid-Infrared Instrument (MIRI) to measure the brightness of mid-infrared light. When the planet is beside the star, the light emitted by both the star and the dayside of the planet reach the telescope, and the system appears brighter. When the planet is behind the star, the light emitted by the planet is blocked and only the starlight reaches the telescope, causing the apparent brightness to decrease.

Astronomers can subtract the brightness of the star from the combined brightness of the star and planet to calculate how much infrared light is coming from the planet’s dayside. This is then used to calculate the dayside temperature.

The graph shows combined data from five separate observations made using MIRI’s F1500W filter, which only allows light with wavelengths ranging from 13.5-16.6 microns to pass through to the detectors. The blue squares are individual brightness measurements. The red circles show measurements that are “binned,” or averaged to make it easier to see the change over time. The decrease in brightness during the secondary eclipse is less than 0.1%. MIRI was able to detect changes as small as 0.027% (or 1 part in 3700).

This is the first thermal emission observation of TRAPPIST-1 b, or any planet as small as Earth and as cool as the rocky planets in the Solar System.

The observations are being repeated using a 12.8-micron filter in order to confirm the results and narrow down the interpretations.

MIRI was developed as a partnership between Europe and the USA: the main partners are ESA, a consortium of nationally funded European institutes, the Jet Propulsion Laboratory (JPL) and the University of Arizona. The instrument was nationally funded by the European Consortium under the auspices of the European Space Agency.

[Image description: At the top of the infographic is a diagram showing a planet moving behind its star (a secondary eclipse). Below the diagram is a graph showing the change in brightness of 15-micron light emitted by the star-planet system over the course of 3.5 hours. The infographic shows that the brightness of the system decreases markedly as the planet moves behind the star.]

Credit:
NASA, ESA, CSA, J. Olmsted (STScI), T. P. Greene (NASA Ames), T. Bell (BAERI), E. Ducrot (CEA), P. Lagage (CEA)

The team used a technique called secondary eclipse photometry, in which MIRI measured the change in brightness from the system as the planet moved behind the star. Although TRAPPIST-1 b is not hot enough to give off its own visible light, it does have an infrared glow. By subtracting the brightness of the star on its own (during the secondary eclipse) from the brightness of the star and planet combined, they were able to successfully calculate how much infrared light is being given off by the planet.

Measuring minuscule changes in brightness

Webb’s detection of a secondary eclipse is itself a major milestone. With the star more than 1,000 times brighter than the planet, the change in brightness is less than 0.1%.

“There was also some fear that we’d miss the eclipse. The planets all tug on each other, so the orbits are not perfect,” said Taylor Bell, the post-doctoral researcher at the Bay Area Environmental Research Institute who analysed the data. “But it was just amazing: The time of the eclipse that we saw in the data matched the predicted time within a couple of minutes.”

Analysis of data from five separate secondary eclipse observations indicates that TRAPPIST-1 b has a dayside temperature of about 500 kelvins, or roughly 230°C. The team thinks the most likely interpretation is that the planet does not have an atmosphere.

Rocky exoplanet TRAPPIST-1 b (temperature comparison)
Comparison of the dayside temperature of TRAPPIST-1 b as measured using Webb’s Mid-Infrared Instrument (MIRI) to computer models showing what the temperature would be under various conditions. The models take into account the known properties of the system, including the planet’s size and density, the temperature of the star, and the planet’s orbital distance. The temperature of the dayside of Mercury is also shown for reference.The dayside brightness of TRAPPIST-1 b at 15 microns corresponds to a temperature of about 500 K (roughly 230°C). This is consistent with the temperature assuming the planet is tidally locked (one side facing the star at all times), with a dark-coloured surface, no atmosphere, and no redistribution of heat from the dayside to the nightside.

If the heat energy from the star were distributed evenly around the planet (for example, by a circulating carbon dioxide-free atmosphere), the temperature at 15 microns would be 400 K (125°C). If the atmosphere had a substantial amount of carbon dioxide, it would emit even less 15-micron light and would appear to be even cooler.

Although TRAPPIST-1 b is hot by Earth standards, it is cooler than the dayside of Mercury, which consists of bare rock and no significant atmosphere. Mercury receives about 1.6 times more energy from the Sun than TRAPPIST-1 b does from its star.

MIRI was developed as a partnership between Europe and the USA: the main partners are ESA, a consortium of nationally funded European institutes, the Jet Propulsion Laboratory (JPL) and the University of Arizona. The instrument was nationally funded by the European Consortium under the auspices of the European Space Agency.

[Image description: Infographic titled, “Rocky Exoplanet TRAPPIST-1 b Dayside Temperature Comparison, MIRI F1500W” showing five planets plotted along a horizontal temperature scale: Earth, TRAPPIST-1 b, Mercury, and two different models of TRAPPIST-1 b.]

Credit:
NASA, ESA, CSA, J. Olmsted (STScI), T. P. Greene (NASA Ames), T. Bell (BAERI), E. Ducrot (CEA), P. Lagage (CEA)

“We compared the results to computer models showing what the temperature should be in different scenarios,” explained Ducrot. “The results are almost perfectly consistent with a blackbody made of bare rock and no atmosphere to circulate the heat. We also didn’t see any signs of light being absorbed by carbon dioxide, which would be apparent in these measurements.”

This research was conducted as part of Guaranteed Time Observation (GTO) program 1177, which is one of eight approved GTO and General Observer (GO) programs designed to help fully characterise the TRAPPIST-1 system. Additional secondary eclipse observations of TRAPPIST-1 b are currently in progress, and now that they know how good the data can be, the team hopes to eventually capture a full phase curve showing the change in brightness over the entire orbit. This will allow them to see how the temperature changes from the day to the nightside and confirm if the planet has an atmosphere or not.

“There was one target that I dreamed of having,” said Lagage, who worked on the development of the MIRI instrument for more than two decades. “And it was this one. This is the first time we can detect the emission from a rocky, temperate planet. It’s a really important step in the story of discovering exoplanets.”

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Local astronomer urges the public to look up – Windsor News Today – windsornewstoday.ca

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If last week’s solar eclipse piqued your interest in astronomy, the Royal Astronomical Society of Canada’s Windsor Chapter plans to show off some of the more dramatic photos and videos members took of the event.

They were stationed along the path of totality along the northern shore of Lake Erie and in the U.S.

“People did take some nice photos with their cellphones, but we have members who took photos and videos with their telescopes,” said member Tom Sobocan. “You’ll see some pretty impressive shots.”

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About 100 members are in the local chapter, which meets every third Tuesday of every month.

Thursday’s meeting is at the Ojibway Nature Centre on Matchette Road. It starts at 7:30, and it’s open to the public. Seating is limited, so Sobocan recommends arriving early.

Astronomers are looking ahead to new wonders in the heavens. Right now, the Pons-Brooks Comet, another once-in-a-lifetime opportunity, is approaching Jupiter in the constellation of Aries.

“If you’re in a dark-sky location, you can see it with the naked eye, and from inside the city, you can see it with binoculars,” said Sobocan. “It may get a little bit brighter going towards the fall, but our members have already photographed it with their telescopes.”

It’s a periodic comet which appears in the night sky once every 71 years.

Sobocan said once-in-a-lifetime events, like last week’s eclipse, inspired many of its existing members, but he hopes some new ones will join the group.

“I hope it inspires them to look up at the sky a little bit more often and realize that everything’s in motion in the sky,” he said. “It’s not stationary.”

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Giant, 82-foot lizard fish discovered on UK beach could be largest marine reptile ever found – Livescience.com

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Scientists have unearthed the remains of a gigantic, 200 million-year-old sea monster that may be the largest marine reptile ever discovered.

The newfound creature is a member of a group called ichthyosaurs, which were among the dominant sea predators during the Mesozoic era (251.9 million to 66 million years ago). The newly described species lived during the end of the Triassic period (251.9 million to 201.4 million years ago).

Ichthyosaurs had already attained massive sizes by the early portion of the Mesozoic, but it was not until the late Triassic that the largest species emerged.

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While the Mesozoic is known as the age of the dinosaurs, ichthyosaurs were not themselves dinosaurs. Instead, they evolved from another group of reptiles. Their evolutionary path closely mirrors that of whales, which evolved from terrestrial mammals that later returned to the sea. And like whales, they breathed air and gave birth to live young.

The newly discovered ichthyosaur species was unearthed in pieces between 2020 and 2022 at Blue Anchor, Somerset in the United Kingdom. The first chunk of the fossil was noticed atop a rock on the beach, indicating that a passerby had found it and set it there for others to examine, the researchers explained in the paper. The researchers published their findings April 17 in the journal PLOS One.

The reptile’s remains are made up of a series of 12 fragments from a surangular bone, which is found in the upper portion of the lower jaw. The researchers estimate the bone was 6.5 feet (2 meters) long and that the living animal was about 82 feet (25 m) long.

The researchers named the sea monster Ichthyotitan severnensis, meaning giant lizard fish of the Severn, after the Severn Estuary where it was found. The team believes it is not only a new species but an entirely new genus of ichthyosaur. More than 100 species are already known.

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A giant pair of swimming Ichthyotitan severnensis. (Image credit: Gabriel Ugueto, CC-BY 4.0)

A number of rib fragments and a coprolite, or fossilized feces, were found in the area as well, but they were not definitively attributed to the same animal.

The sediments in which these specimens were found contained rocks that indicated earthquakes and tsunamis occurred during that time, which suggests that this species lived during a time of intense volcanic activity that may have led to a massive extinction event at the end of the Triassic according to the researchers.

A similar specimen was discovered in Lilstock, Somerset in 2016 and described in 2018. Both were found in what is known at the Westbury Mudstone Formation, within 6 miles (10 kilometers) of each other. This ichthyosaur was estimated to have been as much as 85 feet (26 m) long, although the authors of the latest study believe it was slightly smaller.

The previous contender for the largest marine reptile was another ichthyosaur, Shonisaurus sikanniensis, which was up to 69 feet (21 m) long. S. sikanniensis appeared 13 million years earlier than I. severnensis and was found in British Columbia, making it unlikely that the new discovery represents another specimen of the previously known species.

A similarly massive ichthyosaur called Himalayasaurus tibetensis, which may have reached lengths of 49 feet (15 m), was discovered in Tibet and described in 1972. It dates to the same period, meaning that it probably is not the same species as the new discovery either.

I. severnensis was likely among the last of the giant ichthyosaurs, the researchers claim. Ichthyosaurs persisted into the Cenomanian Age (100.5 million to 93.9 million years ago) of the late Cretaceous period (100.5 million to 66 million years ago). They were eventually supplanted by plesiosaurs — long-necked marine reptiles that went extinct at the end of the Cretaceous, alongside all non-avian dinosaurs.

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Federal government announces creation of National Space Council | RCI – Radio-Canada.ca

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The Canadian Space Agency also received a proposed $8.6 million for its lunar program

Posted: April 17, 2024 7:57 PM

Nicole Mortillaro (new window) · CBC News

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Canada’s space sector received a boost from the federal government in its budget, both in terms of money and vision.

The 2024 budget (new window) included a proposal for $8.6 million in 2024-25 to the Canadian Space Agency (CSA) for the Lunar Exploration Accelerator Program (new window) (LEAP), which invests in technologies for humanity’s return to the moon and beyond.

In addition to the funding, the federal government also announced the creation of a National Space Council, which will be a new whole-of-government approach to space exploration, technology development, and research.

For Space Canada (new window), an organization comprised of roughly 80 space sector companies including some of Canada’s largest, such as Magellan Aerospace (new window)Maritime Launch (new window) and MDA Space (new window), it was a welcome announcement.

We’ve been advocating for it since the inception of our organization, and we were really very happy, and we applaud the federal government’s commitment announced in the budget, said Brian Gallant, CEO of Space Canada.

Gallant said that investment in space is an investment in Canada.

Two-thirds of space sector jobs are STEM jobs. These are good paying solid jobs for Canadians. And on top of that, we have approximately $2.8 billion that is injected into the Canadian economy because of the space sector, he said.

The U.S. formed its National Space Council in 1989, but it was disbanded in 1992 and reestablished in 2017. 

In the 2023 budget (new window), the government announced proposed spending of $1.2 billion over 13 years, that was to begin in 2024-25, to the CSA’s contribution of a lunar utility (new window) vehicle that would assist astronauts on the moon. The as–yet–developed vehicle could help astronauts move cargo from landing sites to habitats, perform science investigations or support them during spacewalks on the surface of the moon.

It also proposed to invest $150 million over five years for the LEAP program.

MDA Space, the company behind Canadarm, was also pleased with the announcement.

Canada has an enviable global competitive advantage in space and the creation of a National Space Council is critical to Canada maintaining that leadership position, CEO Mike Greenley said in an email to CBC News.

Space is now a rapidly growing, highly strategic and competitive domain, and there is a real and urgent need to recognize its importance to the lives of Canadians and to our economy and national security.

The next project for MDA is Canadarm3, which will be part of Lunar Gateway, a international space station that will orbit the moon. It will serve as a sort of jumping-off point for astronauts heading to the moon and eventually beyond.

The Lunar Gateway is a great opportunity for Canada and for MDA Space to not only provide the next generation of Canadarm robotics but to clearly plant our flag as a core national and industry participant in the Artemis era, Greenley said.

Lunar Gateway is set to begin construction no earlier than 2025 (new window), according to NASA.

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