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Curious comet’s rare close approach
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By NASA
This artist’s concept shows interstellar object 1I/2017 U1 (‘Oumuamua) after its discovery in 2017. While itself not a dark comet, ‘Oumuamua’s motion through the solar system has helped researchers better understand the nature of the 14 dark comets discovered so far.European Southern Observatory / M. Kornmesser These celestial objects look like asteroids but act like comets now come in two flavors.
The first dark comet — a celestial object that looks like an asteroid but moves through space like a comet — was reported less than two years ago. Soon after, another six were found. In a new paper, researchers announce the discovery of seven more, doubling the number of known dark comets, and find that they fall into two distinct populations: larger ones that reside in the outer solar system and smaller ones in the inner solar system, with various other traits that set them apart.
The findings were published on Monday, Dec. 9, in the Proceedings of the National Academy of Sciences.
Scientists got their first inkling that dark comets exist when they noted in a March 2016 study that the trajectory of “asteroid” 2003 RM had moved ever so slightly from its expected orbit. That deviation couldn’t be explained by the typical accelerations of asteroids, like the small acceleration known as the Yarkovsky effect.
“When you see that kind of perturbation on a celestial object, it usually means it’s a comet, with volatile material outgassing from its surface giving it a little thrust,” said study coauthor Davide Farnocchia of NASA’s Jet Propulsion Laboratory in Southern California. “But try as we might, we couldn’t find any signs of a comet’s tail. It looked like any other asteroid — just a pinpoint of light. So, for a short while, we had this one weird celestial object that we couldn’t fully figure out.”
Weird Celestial Objects
Farnocchia and the astronomical community didn’t have to wait long for another piece of the puzzle. The next year, in 2017, a NASA-sponsored telescope discovered history’s first documented celestial object that originated outside our solar system. Not only did 1I/2017 U1 (‘Oumuamua) appear as a single point of light, like an asteroid, its trajectory changed as if it were outgassing volatile material from its surface, like a comet.
“‘Oumuamua was surprising in several ways,” said Farnocchia. “The fact that the first object we discovered from interstellar space exhibited similar behaviors to 2003 RM made 2003 RM even more intriguing.”
By 2023, researchers had identified seven solar system objects that looked like asteroids but acted like comets. That was enough for the astronomical community to bestow upon them their own celestial object category: “dark comets.” Now, with the finding of seven more of these objects, researchers could start on a new set of questions.
“We had a big enough number of dark comets that we could begin asking if there was anything that would differentiate them,” said Darryl Seligman, a postdoctoral fellow in the department of Physics at Michigan State University, East Lansing, and lead author of the new paper. “By analyzing the reflectivity,” or albedo, “and the orbits, we found that our solar system contains two different types of dark comets.”
Two Kinds of Dark Comets
The study’s authors found that one kind, which they call outer dark comets, have similar characteristics to Jupiter-family comets: They have highly eccentric (or elliptical) orbits and are on the larger side (hundreds of meters or more across).
The second group, inner dark comets, reside in the inner solar system (which includes Mercury, Venus, Earth, and Mars), travel in nearly circular orbits, and are on the smaller side (tens of meters or less).
Like so many astronomical discoveries, Seligman and Farnocchia’s research not only expands on our knowledge of dark comets, but it also raises several additional questions: Where did dark comets originate? What causes their anomalous acceleration? Could they contain ice?
“Dark comets are a new potential source for having delivered the materials to Earth that were necessary for the development of life,” said Seligman. “The more we can learn about them, the better we can understand their role in our planet’s origin.”
For more information about asteroids and comets, visit:
https://www.jpl.nasa.gov/topics/asteroids/
Small Body Research at JPL NASA Learns More About Interstellar Visitor 'Oumuamua Lesson: Comet on a Stick News Media Contacts
Ian J. O’Neill
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-2649
ian.j.oneill@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Bethany Mauger
Michigan State University, East Lansing
maugerbe@msu.edu
2024-168
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Last Updated Dec 09, 2024 Related Terms
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By NASA
Artist’s concept of a young, newly discovered planet, exposed to observation by a warped debris disk. Credit: Robert Hurt, Caltech-IPAC. The discovery
A huge planet with a long name – IRAS 04125+2902 b – is really just a baby: only 3 million years old. And because such infant worlds are usually hidden inside obscuring disks of debris, it is the youngest planet so far discovered using the dominant method of planet detection.
Key facts
The massive planet, likely still glowing from the heat of its formation, lies in the Taurus Molecular Cloud, an active stellar nursery with hundreds of newborn stars some 430 light-years away. The cloud’s relative closeness makes it a prime target for astronomers. But while the cloud offers deep insight into the formation and evolution of young stars, their planets are usually a closed book to telescopes like TESS, the Transiting Exoplanet Survey Satellite. These telescopes rely on the “transit method,” watching for the slight dip in starlight when a planet crosses the face of its host star. But such planetary systems must be edge-on, from Earth’s vantage point, for the transit method to work. Very young star systems are surrounded by disks of debris, however, blocking our view of any potentially transiting planets.
A research team has just reported an extraordinary stroke of luck. Somehow, the outer debris disk surrounding this newborn planet, IRAS 04125+2902 b, has been sharply warped, exposing the baby world to extensive transit observations by TESS.
Details
While the warped outer disk is a great coincidence, it’s also a great mystery. Possible explanations include a migration of the planet itself, moving closer to the star and, in the process, diverging from the orientation of the outer disk – so that, from Earth, the planet’s orbit is edge-on, crossing the face of the star, but the outer disk remains nearly face-on to us. One problem with this idea: Moving a planet so far out of alignment with its parent disk would likely require another (very large) object in this system. None has been detected so far.
The system’s sun happens to have a distant stellar companion, also a possible culprit in the warping of the outer disk. The angle of the orbit of the companion star, however, matches that of the planet and its parent star. Stars and planets tend to take the gravitational path of least resistance, so such an arrangement should push the disk into a closer alignment with the rest of the system – not into a radical departure.
Another way to get a “broken” outer disk, the study authors say, would not involve a companion star at all. Stellar nurseries like the Taurus Molecular Cloud can be densely packed, busy places. Computer simulations show that rains of infalling material from the surrounding star-forming region could be the cause of disk-warping. Neither simulations nor observations have so far settled the question of whether warped or broken disks are common or rare in such regions.
Fun facts
Combining TESS’s transit measurements with another way of observing planets yields more information about the planet itself. We might call this second approach the “wobble” method. The gravity of a planet tugs its star one way, then another, as the orbiting planet makes its way around the star. And that wobble can be detected by changes in the light from the star, picked up by specialized instruments on Earth. Such “radial velocity” measurements of this planet reveal that its mass, or heft, amounts to no more than about a third of our own Jupiter. But the transit data shows the planet’s diameter is about the same. That means the planet has a comparatively low density and, likely, an inflated atmosphere. So this world probably is not a gas giant like Jupiter. Instead, it could well be a planet whose atmosphere will shrink over time. When it finally settles down, it could become a gaseous “mini-Neptune” or even a rocky “super-Earth.” These are the two most common planet types in our galaxy – despite the fact that neither type can be found in our solar system.
The discoverers
A science team led by astronomer Madyson G. Barber of the University of North Carolina at Chapel Hill published the study, “A giant planet transiting a 3 Myr protostar with a misaligned disk,” in the journal Nature in November 2024.
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By NASA
Name: Matthew Kowalewski
Title: Dragonfly Mass Spectrometer (DraMS) Lead Instrument Systems Engineer
Formal Job Classification: Aerospace Engineer
Organization: Instrument and Payload Systems Engineering Branch (Code 592)
Matthew Kowalewski is the lead instrument systems engineer for NASA’s Dragonfly Mass Spectrometer (DraMS). Photo courtesy of Matthew Kowalewski What do you do and what is most interesting about your role here at Goddard?
As the DraMS lead instrument systems engineer for NASA’s Dragonfly mission, I lead the coordinated technical development, integrating systems and making sure communications across subsystems is maintained within the instruments as well as with the lander. I enjoy the diversity and complexity of this instrument.
What do you enjoy most about your current position as the DraMS lead instrument systems engineer?
I started this position in March 2023 and it has been like drinking from a fire hose ever since, but in a good way. The complexity of the instrument and the number of subsystems means this is really three separate instruments in one, and that makes my job exciting. I have to keep up with a range of disciplines across everything that Goddard does including mechanisms, lasers, mass spectrometers, gas flow systems, mechanical systems, thermal systems and electrical systems.
I am always challenged and excited by those challenges too. Everything we do is necessary to meet the broad science requirements. Our goal is studying prebiotic chemistry on the surface of Titan.
What is your educational background? Why did you become an aerospace engineer?
I have a B.A. in astronomy and physics from Boston University and a master’s in physics from Johns Hopkins University.
As a child, I was more interested in astronomy and physics. In college, I developed an extreme interest in experimental physics including the engineering required to perform these experiments.
How did you come to Goddard?
After college, I worked in missile defense for a private company supporting the Midcourse Space Experiment. After three years, in 1998, my wife and I wanted to move closer to family, so I came to Goddard as an instrument engineer supporting the Total Ozone Mapping Spectrometer-Earth Probe (TOMS/EP) mission. I have also supported the Ozone Monitoring Instrument on Aura, The Ozone Mapping Profiler Suite (OMPS) on Suomi NPP and JPSS, various airborne field campaigns, and the New Opportunities Office.
What interesting field work did you do prior to joining DraMS?
I largely did field work supporting Earth science research and new business development. We flew remote sensing instruments on high altitude aircraft in the United States, Costa Rica, South Korea [whose official name is the Republic of Korea], and Canada. Most field campaigns lasted about a month where we were housed in hotels or military bases. While supporting the New Opportunities Office, we developed instrument and mission concepts, evaluated and prioritized technologies, and fostered relationships with industry, universities, and other government organizations.
How do you lead across multiple teams?
I lead a large team engineers and technicians spanning across over six teams. Communication is the key. I rely on the expertise of our systems team and all of the subsystem leads. We have daily and weekly meetings where everyone is heard and they are free to approach me whenever they have concerns.
I try to encourage open discussions including contrarian thoughts and ideas. I listen to all the options and opinions in an attempt to make the best-informed decision. Then I move forward with my decision.
In a cost- and schedule-constrained environment, like most missions are, we cannot get stuck in the decision-making process. At some point, a decision needs to be made and the team then moves forward.
Where have you traveled for work?
I have been to multiple NASA centers and military bases in this country. In addition to Costa Rica, South Korea and Canada, I have also been to the Netherlands and France for mission development.
What is the most memorable moment you have had at Goddard?
In 2003, I was supporting the space shuttle Columbia mission, STS-107. We had a small payload in the shuttle cargo bay called a Hitchhiker. I was second shift in the Hitchhiker mission operations center. I got to interact with the astronauts both prelaunch and on orbit. It meant a lot to me. My last shift was just prior to their reentry. It really impacted me when I learned, after my shift, that the shuttle disintegrated with all hands lost.
I had the honor of meeting these astronauts. It reminded me of the importance of the work that we do as we continue sending astronauts into orbit for missions.
When you mentor someone, what do you advise them to do?
I tell them to learn as much about everything that they can. For example, if they are an engineer, they should learn about science and other disciplines because a broad knowledge base will help them in the future. They will also learn why building a small piece of hardware is important for accomplishing the mission’s science goals. An electrical engineer building a circuit is actually building something for a far larger purpose.
It is also very important to get along with others. We work with others every day, in all aspects of our lives, and we have to understand their perspectives and respect their opinions. There is more to our jobs than building things. Establishing relationships with others is what truly allows us to accomplish our goals.
What do you do for fun?
I have four kids and enjoy spending time with them. I coach soccer, mentor a robotics club, and participate in endurance swim races. This is my second year as a mentor to my son’s robotics club, which participates in an annual, national robotics competition to build a robot from scratch. This year we have a highly mobile, fast robot with a multi-jointed arm to manipulate objects. I think we have a good shot at going to nationals.
Who would you like to thank?
I wish to thank my wife Angie for supporting me over all these years as my career developed. She was often home alone with four kids during long stints of travel. I would not be where I am without her.
I also owe much to my mentors, Scott Janz, Glenn Jaross, and Jay Al-Saadi for all their guidance, support and opportunities over the many years. Nobody can work alone, no matter how smart you are.
What is your “five-word or phrase memoir”? A five-word or phrase memoir describes something in just five words or phrases.
Understanding. Compassionate. Persistent. Hard-working. Curious about too many things.
By Elizabeth M. Jarrell
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Conversations With Goddard is a collection of Q&A profiles highlighting the breadth and depth of NASA’s Goddard Space Flight Center’s talented and diverse workforce. The Conversations have been published twice a month on average since May 2011. Read past editions on Goddard’s “Our People” webpage.
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Last Updated Nov 12, 2024 EditorRob GarnerContactRob Garnerrob.garner@nasa.govLocationGoddard Space Flight Center Related Terms
People of Goddard Dragonfly Goddard Space Flight Center People of NASA View the full article
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By NASA
NASA/Eric Bordelon Comet C/2023 A3 (Tsuchinshan-ATLAS) passes over NASA’s Michoud Assembly Facility in New Orleans in this Oct. 13, 2024, image. This comet comes from the Oort Cloud, far beyond Pluto and the most distant edges of the Kuiper Belt. Though Comet C/2023 A3 will be visible through early November, the best time to observe is between now and Oct. 24.
Image credit: NASA/Eric Bordelon
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