A newly discovered “ultrahot Jupiter” has the shortest orbit of any known gas giant.

The hunt for planets beyond our solar system has turned up more than 4,000 far-flung worlds, orbiting stars thousands of  light years from Earth. These extrasolar planets are a veritable menagerie, from rocky super-Earths and miniature Neptunes to colossal gas giants.

Among the more confounding planets discovered to date are “hot Jupiters” —  massive balls of gas that are about the size of our own Jovian planet but that zing around their stars in less than 10 days, in contrast to Jupiter’s plodding, 12-year orbit. Scientists have discovered about 400 hot Jupiters to date. But exactly how these weighty whirlers came to be remains one of the biggest unsolved mysteries in planetary science.

Now, astronomers have discovered one of the most extreme ultrahot Jupiters  — a gas giant that is about five times Jupiter’s mass and blitzes around its star in just 16 hours. The planet’s orbit is the shortest of any known gas giant to date.

Due to its extremely tight orbit and proximity to its star, the planet’s day side is estimated to be at around 3,500 Kelvin, or close to 6,000 degrees Fahrenheit — about as hot as a small star. This makes the planet, designated TOI-2109b, the second hottest detected so far.

Judging from its properties, astronomers believe that TOI-2109b is in the process of “orbital decay,” or spiraling into its star, like bathwater circling the drain. Its extremely short orbit is predicted to cause the planet to spiral toward its star faster than other hot Jupiters.

The discovery, which was made initially by NASA’s Transiting Exoplanet Survey Satellite (TESS), an MIT-led mission, presents a unique opportunity for astronomers to study how planets behave as they are drawn in and swallowed by their star.

“In one or two years, if we are lucky, we may be able to detect how the planet moves closer to its star,” says Ian Wong, lead author of the discovery, who was a postdoc at MIT during the study and has since moved to NASA Goddard Space Flight Center.  “In our lifetime we will not see the planet fall into its star. But give it another 10 million years, and this planet might not be there.”

The discovery is reported today in the Astronomical Journal and is the result of the work of a large collaboration that included members of MIT’s TESS science team and researchers from around the world.

Transit track

On May 13, 2020, NASA’s TESS satellite began observing TOI-2109, a star located in the southern portion of the Hercules constellation, about 855 light years from Earth. The star was identified by the mission as the 2,109th “TESS Object of Interest,” for the possibility that it might host an orbiting planet.

Over nearly a month, the spacecraft collected measurements of the star’s light, which the TESS science team then analyzed for transits — periodic dips in starlight that might indicate a planet passing in front of and briefly blocking a small fraction of the star’s light. The data from TESS confirmed that the star indeed hosts an object that transits about every 16 hours.

The team notified the wider astronomy community, and shortly after, multiple ground-based telescopes followed up over the next year to observe the star more closely over a range of frequency bands. These observations, combined with TESS’ initial detection, confirmed the transiting object as an orbiting planet, which was designated TOI-2109b.

“Everything was consistent with it being a planet, and we realized we had something very interesting and relatively rare,” says study co-author Avi Shporer, a research scientist at MIT’s Kavli Institute for Astrophysics and Space Research.

Day and night

By analyzing measurements over various optical and infrared wavelengths, the team determined that TOI-2109b is about five times as massive as Jupiter, about 35 percent larger, and extremely close to its star, at a distance of about 1.5 million miles out. Mercury, by comparison, is around 36 million miles from the Sun.

The planet’s star is roughly 50 percent larger in size and mass compared to our Sun. From the observed properties of the system, the researchers estimated that TOI-2109b is spiraling into its star at a rate of 10 to 750 milliseconds per year — faster than any hot Jupiter yet observed.

Given the planet’s dimensions and proximity to its star, the researchers determined TOI-2109b to be an ultrahot Jupiter, with the shortest orbit of any known gas giant. Like most hot Jupiters, the planet appears to be tidally locked, with a perpetual day and night side, similar to the Moon with respect to the Earth. From the month-long TESS observations, the team was able to witness the planet’s varying brightness as it revolves about its axis. By observing the planet pass behind its star (known as a secondary eclipse) at both optical and infrared wavelengths, the  researchers estimated that the day side reaches temperatures of more than 3,500 Kelvin.

“Meanwhile, the planet’s night side brightness is below the sensitivity of the TESS data, which raises questions about what is really happening there,” Shporer says. “Is the temperature there very cold, or does the planet somehow take heat on the day side and transfer it to the night side? We’re at the beginning of trying to answer this question for these ultrahot Jupiters.”

The researchers hope to observe TOI-2109b with more powerful tools in the near future, including the Hubble Space Telescope and the soon-to-launch James Webb Space Telescope. More detailed observations could illuminate the conditions hot Jupiters undergo as they fall into their star.

“Ultrahot Jupiters such as TOI-2109b constitute the most extreme subclass of exoplanet,” Wong says. “We have only just started to understand some of the unique physical and chemical processes that occur in their atmospheres — processes that have no analogs in our own solar system.”

Future observations of TOI-2109b may also reveal clues to how such dizzying systems come to be in the first place. “From the beginning of exoplanetary science, hot Jupiters have been seen as oddballs,” Shporer says. “How does a planet as massive and large as Jupiter reach an orbit that is only a few days long? We don’t have anything like this in our solar system, and we see this as an opportunity to study them and help explain their existence.”

This research was supported, in part, by NASA.

TOI-2109: An Ultrahot Gas Giant on a 16 hr Orbit

Featured image: The newly discovered planet is relatively close to its star, at a distance of only about 1.5 million miles out. Credits:Image: NASA, ESA and G. Bacon

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Provided by MIT

Sofia Bergman, Swedish Institute of Space Physics (IRF) and Umeå University, will defend her doctoral thesis on low-energy ions around comet 67P/Churyumov-Gerasimenko on 26 November. Observing low energy ions is notoriously difficult because their properties are affected greatly by the spacecraft which observes them. Sofia has developed new methods to do this. Using her work, scientists can study low-energy ions around comets and in a variety of other places in the Solar System.

Comets have an environment of plasma which contains a large number of ions with low energies. It is necessary to understand these low-energy ions’ properties in order to understand the physical processes occurring around the comet.

As low-energy ions are difficult to measure Sofia Bergman devised a new method to analyze measurements of these ions around comet 67P/Churyumov-Gerasimenko in her thesis.

“A spacecraft interacts with its environment, which leads to an accumulation of charge on the surface of the spacecraft. This is problematic for the measurements of low-energy ions, since the ions are affected by the spacecraft before they are detected, changing both their energy and travel direction. We want to know the original properties of the ions, before they were affected by the spacecraft, which is now possible with the method that I have developed in my thesis”, Sofia Bergman explains.

In the thesis, data from IRF’s ion mass spectrometer ICA (Ion Composition Analyzer) on board Rosetta have been analysed. ICA can measure the energy and travel direction of ions with very low energies, but because of the influence of the spacecraft potential on the measurements the low-energy data from ICA have previously been difficult to interpret.

“For the first time, we have now been able to determine the flow directions of low-energy ions observed by ICA at comet 67P/Churyumov-Gerasimenko”, Sofia Bergman says. “The results were surprising. We see a large amount of ions flowing inward towards the comet nucleus, instead of outward as we had expected.”

Comets are interesting to study when we want to understand how the solar wind is interacting with different bodies in the Solar System. The comets’ elliptical orbits cause the environment around them to change dramatically. As the distance from the comet to the Sun changes, we can observe how a magnetosphere is being formed around the comet. Low-energy ions are important for this interaction and not only at comets:

“The method that I have developed in my thesis can also be used to study low-energy ions around other bodies in the Solar System. The analysis of such ions has previously been very limited due to the difficulties of interpreting the measurements”, says Sofia Bergman.

Sofia Bergman was born and raised in Borlänge, Sweden.

About the dissertation:
Sofia Bergman defends her thesis “Low-Energy Ions Around Comet 67P/Churyumov-Gerasimenko” in Ljusårssalen at IRF in Kiruna, Sweden, on Friday 26 November at 9:00.
The opponent is Prof Stein Håland from Max-Planck Institute for Solar System Research, Göttingen, Germany and Birkeland Centre for Space Science, University of Bergen, Norway and the University Centre in Svalbard, Longyearbyen, Norway.

Read the whole thesis

Read more about the Swedish Institute of Space Physics

Featured image: Sofia Bergman’s thesis gives scientists unique possibilities to study low-energy ions in space. låg energi. ImageInstitutet för rymdfysik

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Provided by UMEA University

Findings also include a distinctive planetary system with two gas giants

UCLA astronomers have identified 366 new exoplanets, thanks in large part to an algorithm developed by a UCLA postdoctoral scholar. Among their most noteworthy findings is a planetary system that comprises a star and at least two gas giant planets, each roughly the size of Saturn and located unusually close to one another.

The discoveries are described in a paper published today in the Astronomical Journal.

The term “exoplanets” is used to describe planets outside of our own solar system. The number of exoplanets that have been identified by astronomers numbers fewer than 5,000 in all, so the identification of hundreds of new ones is a significant advance. Studying such a large new group of bodies could help scientists better understand how planets form and orbits evolve, and it could provide new insights about how unusual our solar system is.

“Discovering hundreds of new exoplanets is a significant accomplishment by itself, but what sets this work apart is how it will illuminate features of the exoplanet population as a whole,” said Erik Petigura, a UCLA astronomy professor and co-author of the research.

The paper’s lead author is Jon Zink, who earned his doctorate from UCLA in June and is currently a UCLA postdoctoral scholar. He and Petigura, as well as an international team of astronomers called the Scaling K2 project, identified the exoplanets using data from the NASA Kepler Space Telescope’s K2 mission.

The discovery was made possible by a new planet detection algorithm that Zink developed. One challenge in identifying new planets is that reductions in staller brightness may originate from the instrument or from an alternative astrophysical source that mimics a planetary signature. Teasing out which ones are which requires extra investigation, which traditionally has been extremely time consuming and can only be accomplished through visual inspection. Zink’s algorithm is able to separate which signals indicate planets and which are merely noise.

“The catalog and planet detection algorithm that Jon and the Scaling K2 team came devised is a major breakthrough in understanding the population of planets,” Petigura said. “I have no doubt they will sharpen our understanding of the physical processes by which planets form and evolve.”

Kepler’s original mission came to an unexpected end in 2013 when a mechanical failure left the spacecraft unable to precisely point at the patch of sky it had been observing for years.

But astronomers repurposed the telescope for a new mission known as K2, whose objective is to identify exoplanets near distant stars. Data from K2 is helping scientists understand how stars’ location in the galaxy influences what kind of planets are able to form around them. Unfortunately, the software used by the original Kepler mission to identify possible planets was unable to handle the complexities of the K2 mission, including the ability to determine the planets’ size and their location relative to their star.

Previous work by Zink and collaborators introduced the first fully automated pipeline for K2, with software to identify likely planets in the processed data.

For the new study, the researchers used the new software to analyze the entire dataset from K2 — about 500 terabytes of data encompassing more than 800 million images of stars — to create a “catalog” that will soon be incorporated into NASA’s master exoplanet archive. The researchers used UCLA’s Hoffman2 Cluster to process the data.

In addition to the 366 new planets the researchers identified, the catalog lists 381 other planets that had been previously identified.

Zink said the findings could be a significant step toward helping astronomers understand which types of stars are most likely to have planets orbiting them and what that indicates about the building blocks needed for successful planet formation.

“We need to look at a wide range of stars, not just ones like our sun, to understand that,” he said.

The discovery of the planetary system with two gas giant planets was also significant because it’s rare to find gas giants — like Saturn in our own solar system — as close to their host star as they were in this case. The researchers cannot yet explain why it occurred there, but Zink said that makes the finding especially useful because it could help scientists form a more accurate understanding of the parameters for how planets and planetary systems develop.

“The discovery of each new world provides a unique glimpse into the physics that play a role in planet formation,” he said.

Featured image: UCLA researchers identified 366 new exoplanets using data from the Kepler Space Telescope, including 18 planetary systems similar to the one illustrated here, Kepler-444, which was previously identified using the telescope. ©
Tiago Campante/Peter Devine via NASA

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Provided by UCLA

In the strange, dark world of the ocean floor, underwater fissures, called hydrothermal vents, host complex communities of life. These vents belch scorching hot fluids into extremely cold seawater, creating the chemical forces necessary for the small organisms that inhabit this extreme environment to live.

In a newly published study, biogeoscientists Jeffrey Dick and Everett Shock have determined that specific hydrothermal seafloor environments provide a unique habitat where certain organisms can thrive. In so doing, they have opened up new possibilities for life in the dark at the bottom of oceans on Earth, as well as throughout the solar system. Their results have been published in the Journal of Geophysical Research: Biogeosciences.

On land, when organisms get energy out of the food they eat, they do so through a process called cellular respiration, where there is an intake of oxygen and the release of carbon dioxide. Biologically speaking, the molecules in our food are unstable in the presence of oxygen, and it is that instability that is harnessed by our cells to grow and reproduce, a process called biosynthesis.

But for organisms living on the seafloor, the conditions for life are dramatically different.

“On land, in the oxygen-rich atmosphere of Earth, it is familiar to many people that making the molecules of life requires energy,” said co-author Shock of Arizona State University’s School of Earth and Space Exploration and the School of Molecular Sciences. “In stunning contrast, around hydrothermal vents on the seafloor, hot fluids mix with extremely cold seawater to produce conditions where making the molecules of life releases energy.”

In deep-sea microbial ecosystems, organisms thrive near vents where hydrothermal fluid mixes with ambient seawater. Previous research led by Shock found that the biosynthesis of basic cellular building blocks, like amino acids and sugars, is particularly favorable in areas where the vents are composed of ultramafic rock (igneous and meta-igneous rocks with very low silica content), because these rocks produce the most hydrogen.

Besides basic building blocks like amino acids and sugars, cells need to form larger molecules, or polymers, also known as biomacromolecules. Proteins are the most abundant of these molecules in cells, and the polymerization reaction (where small molecules combine to produce a larger biomolecule) itself requires energy in almost all conceivable environments.

“In other words, where there is life, there is water, but water needs to be driven out of the system for polymerization to become favorable,” said lead author Dick, who was a postdoctoral scholar at ASU when this research began and who is currently a geochemistry researcher in the School of Geosciences and Info-Physics at Central South University in Changsha, China. “So, there are two opposing energy flows: release of energy by biosynthesis of basic building blocks, and the energy required for polymerization.”

What Dick and Shock wanted to know is what happens when you add them up: Do you get proteins whose overall synthesis is actually favorable in the mixing zone?

They approached this problem by using a unique combination of theory and data.

From the theoretical side, they used a thermodynamic model for the proteins, called “group additivity,” which accounts for the specific amino acids in protein sequences as well as the polymerization energies. For the data, they used all the protein sequences in an entire genome of a well-studied vent organism called Methanocaldococcus jannaschii.

By running the calculations, they were able to show that the overall synthesis of almost all the proteins in the genome releases energy in the mixing zone of an ultramafic-hosted vent at the temperature where this organism grows the fastest, at around 185 degrees Fahrenheit (85 Celsius). By contrast, in a different vent system that produces less hydrogen (a basalt-hosted system), the synthesis of proteins is not favorable.

“This finding provides a new perspective on not only biochemistry but also ecology because it suggests that certain groups of organisms are inherently more favored in specific hydrothermal environments,” Dick said. “Microbial ecology studies have found that methanogens, of which Methanocaldococcus jannaschii is one representative, are more abundant in ultramafic-hosted vent systems than in basalt-hosted systems. The favorable energetics of protein synthesis in ultramafic-hosted systems are consistent with that distribution.”

For next steps, Dick and Shock are looking at ways to use these energetic calculations across the tree of life, which they hope will provide a firmer link between geochemistry and genome evolution.

“As we explore, we’re reminded time and again that we should never equate where we live as what is habitable to life,” Shock said.

Featured image: A chimney structure from the Sea Cliff hydrothermal vent field located more than 8,800 feet (2,700 meters) below the sea’s surface at the submarine boundary of the Pacific and Gorda tectonic plates. Photo by Ocean Exploration Trust

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Provided by Arizona State University

A team of researchers at the Instituto de Astrofísica de Canarias (IAC) and the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Mexico, has discovered lithium in the oldest and coldest brown dwarf where the presence of this valuable element has been confirmed so far. This substellar object, called Reid 1B, preserves intact the earliest known lithium deposit in our cosmic neighbourhood, dating back to a time before the formation of the binary system to which it belongs. The discovery was made using the OSIRIS spectrograph on the Gran Telescopio Canarias (GTC), at the Roque de los Muchachos Observatory (Garafía, La Palma), in the Canary Islands. The study has just been published in the journal Monthly Notices of the Royal Astronomical Society.

Brown dwarfs, also known as “coffee coloured dwarfs” or “failed stars” are the natural link between stars and planets. They are more massive than Jupiter but now sufficiently to burn hydrogen, which is the fuel the stars use to shine. For that reason these substellar objects were not observed until observers detected them in the mid 1990’s. They are particularly interesting because it was predicted that some of them could preserve intact their content of lithium, sometimes known as “white petroleum” because of its rarity and its relevance.

In the past twenty years astronomers have detected, and followed the orbital motions of binaries formed by brown dwarfs in the solar neighbourhood. They have determined their masses dynamically using Kepler’s laws, the mathematical formulae produced in the XVII century by Johannes Kepler to describe the motions of astronomical bodies moving under the effects of their mutual gravitation, such as the system formed by the Earth and the Sun. In some of these systems the primary component has a mass sufficient to burn lithium while the secondary may not have this mass. However until now the theoretical models had not been put to the test.

Using the OSIRIS spectrograph on the Gran Telescopio Canarias (GTC, or Grantecan) currently the largest optical and infrared telescope in the world, at the Roque de los Muchachos Observatory (ORM), a team of researchers at the Instituto de Astrofísica de Canarias (IAC) and the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) made high sensitivity spectroscopic observations, between February and August this year, of two binaries whose components are brown dwarfs.

They did not detect lithium in three of them, but they did find it in Reid 1B, the faintest and coolest of the four. Doing this they made a remarkable discovery, a deposit of cosmic lithium which is not destroyed, whose origin dates back before the formation of the system to which Reid 1B belongs. It is, in fact, the coolest, faintest extrasolar object where lithium has been found, in a quantity 13 thousand times greater than the amount there is on Earth. This object, which has an age of 1.100 million years, and a dynamical mass 41 times bigger than that of Jupiter (the largest planet in the Solar System), is 16.9 light years away from us.

A chest of hidden treasure

Observations of lithium in brown dwarfs allow us to estimate their masses with a degree of accuracy, based on nuclear reactions. The thermonuclear masses found this way must be consistent with the dynamical masses found, with less uncertainty, from orbital analysis. However the researchers have found that the lithium is preserved up to a dynamical mass which is 10% lower than that predicted by the most recent theoretical models. This discrepancy seems to be significant, and suggests that there is something in the behaviour of brown dwarfs that we still don’t understand.

“We have been following the trail of lithium in brown dwarfs for three decades” says Eduardo Lorenzo Martín Guerrero de Escalante, Research Professor of the Higher Council for Scientific Research (CSIC) at the IAC who is the first author of the article, “and finally we have been able to make a precise determination of the boundary in mass between its preservation and its destruction, and compare this with the theoretical predictions”. The researcher adds that “there are thousands of millions of brown dwarfs in the Milky Way. The lithium contained in brown dwarfs is the largest known deposit of this valuable element in our cosmic neighbourhood”.

Carlos del Burgo Díaz co-author of the article, a researcher at the INAOE, a public research centre of the Mexican CONACYT, explains that “although primordial lithium was created 13.800 million years ago, together with hydrogen and helium, as a result of he nuclear reactions in the primordial fireball of the Big Bang, now there is as much as four times more lithium in the Universe”. According to this researcher “although this element can be destroyed, it is also created in explosive events such as novae and supernovae, so that brown dwarfs such as Reid 1B can wrap it up and protect it as if it was a chest of hidden treasure”.

This research has been financed by funding from the Spanish Ministry of Economic Affairs and Digital Transformation (MINECO) and by the European Fund for Regional Developomente (FEDER) via project PID2019-109522GB-C53.

The Gran Telescopio Canarias, and the Observatories of the Instituto de Astrofísica de Canarias (IAC) are part of the network of Singular Scientific and Technical Infrastructures (ICTS) of Spain.

Article: “New constraints on the minimum mass for thermonuclear lithium burning in brown dwarfs”, Monthly Notices of the Royal Astronomical Society; Martín, Eduardo L.; Lodieu, Nicolas; del Burgo, Carlos; octubre de 2021.

DOI: 10.1093/mnras/stab2969
arXiv: arXiv:2110.11982
Bibcode: 2021MNRAS.tmp.2787M 

*Figure caption: The Spanish-Mexican team has found that the boundary between those objects which destroy lithium and those which preserve it lies at 51.5 times the mass of Jupiter. The brown dwarf Reid 1B is a major deposti fo lithium which will never be destroyed. Planets such as Jupiter and the Earth are even less massive and do not destroy their lithium. The Sun has destroyed all the lithium that was in its nucleus and preserves some in its upper layers, which are slowly mixing with its interior. Credit: Gabriel Pérez Díaz, SMM (IAC)

Caption to the animation: The dynamical masses of the binary systems are measured by following their orbital motions and applying Kepler’s laws. These masses are very accurate, and should coincide exactly with the masses which are obtained from the nuclear reactions which take place in the components of these systems. However when one compares the dynamical masses with the nuclear masses, the balance is tipped to one side, which means changes have to be made to obtain an equilibrium to deepen our understanding of the properties of these substellar objects. Credit: Gabriel Pérez Díaz, SMM (IAC)

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