Friday, February 14, 2020

PLEASE Select the 'Trident' Mission, NASA! Thanks!

An image of Neptune's moon Triton that was taken by NASA's Voyager 2 spacecraft in August of 1989.

NASA Selects Four Possible Missions to Study the Secrets of the Solar System (Press Release - February 13)

Two NASA-JPL proposals are among the selections: Trident would explore Neptune's moon Triton, while Veritas aims to map Venus' surface to determine the planet's geologic history.

NASA has selected four Discovery Program investigations to develop concept studies for new missions. Although they're not official missions yet and some ultimately may not be chosen to move forward, the selections focus on compelling targets and science that are not covered by NASA's active missions or recent selections. Final selections will be made next year.

NASA's Discovery Program invites scientists and engineers to assemble a team to design exciting planetary science missions that deepen what we know about the solar system and our place in it. These missions will provide frequent flight opportunities for focused planetary science investigations. The goal of the program is to address pressing questions in planetary science and increase our understanding of our solar system.

"These selected missions have the potential to transform our understanding of some of the solar system's most active and complex worlds," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate. "Exploring any one of these celestial bodies will help unlock the secrets of how it, and others like it, came to be in the cosmos."

Each of the four nine-month studies will receive $3 million to develop and mature concepts and will conclude with a Concept Study Report. After evaluating the concept studies, NASA will continue development of up to two missions towards flight.

The proposals were chosen based on their potential science value and feasibility of development plans following a competitive peer-review process.

The selected proposals are:


Trident would explore Triton, a unique and highly active icy moon of Neptune, to understand pathways to habitable worlds at tremendous distances from the Sun. NASA's Voyager 2 mission showed that Triton has active resurfacing - generating the second-youngest surface in the solar system - with the potential for erupting plumes and an atmosphere. Coupled with an ionosphere that can create organic snow and the potential for an interior ocean, Triton is an exciting exploration target to understand how habitable worlds may develop in our solar system and others. Using a single flyby, Trident would map Triton, characterize active processes and determine whether the predicted subsurface ocean exists. Louise Prockter of the Lunar and Planetary Institute/Universities Space Research Association in Houston is the principal investigator. NASA's Jet Propulsion Laboratory in Pasadena, California, would provide project management.

VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy)

VERITAS would map Venus' surface to determine the planet's geologic history and understand why Venus developed so differently than the Earth. Orbiting Venus with a synthetic aperture radar, VERITAS charts surface elevations over nearly the entire planet to create three-dimensional reconstructions of topography and confirm whether processes, such as plate tectonics and volcanism, are still active on Venus. VERITAS would also map infrared emissions from the surface to map Venus' geology, which is largely unknown. Suzanne Smrekar of NASA's Jet Propulsion Laboratory in Pasadena, California, is the principal investigator. JPL would provide project management.

DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus)

DAVINCI+ would analyze Venus' atmosphere to understand how it formed and evolved and determine whether Venus ever had an ocean. DAVINCI+ plunges through Venus' inhospitable atmosphere to precisely measure its composition down to the surface. The instruments are encapsulated within a purpose-built descent sphere to protect them from the intense environment of Venus. The "+" in DAVINCI+ refers to the imaging component of the mission, which includes cameras on the descent sphere and orbiter designed to map surface rock-type. The last U.S.-led, in-situ mission to Venus was in 1978. The results from DAVINCI+ have the potential to reshape our understanding of terrestrial planet formation in our solar system and beyond. James Garvin of NASA's Goddard Space Flight Center in Greenbelt, Maryland, is the principal investigator. Goddard would provide project management.

Io Volcano Observer (IVO)

IVO would explore Jupiter's moon Io to learn how tidal forces shape planetary bodies. Io is heated by the constant crush of Jupiter's gravity and is the most volcanically active body in the solar system. Little is known about Io's specific characteristics, such as whether a magma ocean exists in its interior. Using close-in flybys, IVO would assess how magma is generated and erupted on Io. The mission's results could revolutionize our understanding of the formation and evolution of rocky, terrestrial bodies, as well as icy ocean worlds in our solar system and extrasolar planets across the universe. Alfred McEwen of the University of Arizona in Tucson is the principal investigator. The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, would provide project management.

The concepts were chosen from proposals submitted in 2019 under NASA Announcement of Opportunity (AO) NNH19ZDA010O, Discovery Program. The selected investigations will be managed by the Planetary Missions Program Office at NASA's Marshall Space Flight Center in Huntsville, Alabama, as part of the Discovery Program. The Discovery Program conducts space science investigations in the Planetary Science Division of NASA's Science Mission Directorate, guided by NASA's agency priorities and the Decadal Survey process of the National Academy of Sciences.

Established in 1992, NASA's Discovery Program has supported the development and implementation of over 20 missions and instruments. These selections are part of the ninth Discovery Program competition.

Source: Jet Propulsion Laboratory

Thursday, February 13, 2020

New Horizons Update: New Information Revealed About Kuiper Belt Object 'Arrokoth'...

A high-resolution image of the Kuiper Belt object Arrokoth that was taken by NASA's New Horizons spacecraft from 4,109 miles (6,628 kilometers) away...on January 1, 2019.
NASA / Johns Hopkins Applied Physics Laboratory / Southwest Research Institute, National Optical Astronomy Observatory

New Horizons Team Uncovers a Critical Piece of the Planetary Formation Puzzle (News Release)

Data from NASA’s New Horizons mission are providing new insights into how planets and planetesimals – the building blocks of the planets – were formed.

The New Horizons spacecraft flew past the ancient Kuiper Belt object Arrokoth (2014 MU69) on Jan. 1, 2019, providing humankind’s first close-up look at one of the icy remnants of solar system formation in the vast region beyond the orbit of Neptune. Using detailed data on the object’s shape, geology, color and composition – gathered during a record-setting flyby that occurred more than four billion miles from Earth – researchers have apparently answered a longstanding question about planetesimal origins, and therefore made a major advance in understanding how the planets themselves formed.

The team reports those findings in a set of three papers in the journal Science, and at a media briefing Feb. 13 at the annual American Association for the Advancement of Science meeting in Seattle.

“Arrokoth is the most distant, most primitive and most pristine object ever explored by spacecraft, so we knew it would have a unique story to tell,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado. “It’s teaching us how planetesimals formed, and we believe the result marks a significant advance in understanding overall planetesimal and planet formation.”

The first post-flyby images transmitted from New Horizons last year showed that Arrokoth had two connected lobes, a smooth surface and a uniform composition, indicating it was likely pristine and would provide decisive information on how bodies like it formed. These first results were published in Science last May.

“This is truly an exciting find for what is already a very successful and history-making mission” said Lori Glaze, director of NASA's Planetary Science Division. “The continued discoveries of NASA’s New Horizons spacecraft astound as it reshapes our knowledge and understanding of how planetary bodies form in solar systems across the universe.”

Over the following months, working with more and higher-resolution data as well as sophisticated computer simulations, the mission team assembled a picture of how Arrokoth must have formed. Their analysis indicates that the lobes of this “contact binary” object were once separate bodies that formed close together and at low velocity, orbited each other, and then gently merged to create the 22-mile long object New Horizons observed.

This indicates Arrokoth formed during the gravity-driven collapse of a cloud of solid particles in the primordial solar nebula, rather than by the competing theory of planetesimal formation called hierarchical accretion. Unlike the high-speed collisions between planetesimals in hierarchical accretion, in particle-cloud collapse, particles merge gently, slowly growing larger.

“Just as fossils tell us how species evolved on Earth, planetesimals tell us how planets formed in space,” said William McKinnon, a New Horizons co-investigator from Washington University in St. Louis, and lead author of an Arrokoth formation paper in Science this week. “Arrokoth looks the way it does not because it formed through violent collisions, but in more of an intricate dance, in which its component objects slowly orbited each other before coming together.”

Two other important pieces of evidence support this conclusion. The uniform color and composition of Arrokoth’s surface shows the KBO formed from nearby material, as local cloud collapse models predict, rather than a mishmash of matter from more separated parts of the nebula, as hierarchical models might predict.

The flattened shapes of each of Arrokoth’s lobes, as well as the remarkably close alignment of their poles and equators, also point to a more orderly merger from a collapse cloud. Further still, Arrokoth’s smooth, lightly cratered surface indicates its face has remained well preserved since the end of the planet formation era.

“Arrokoth has the physical features of a body that came together slowly, with ‘local’ materials in the solar nebula,” said Will Grundy, New Horizons composition theme team lead from Lowell Observatory in Flagstaff, Arizona, and the lead author of a second Science paper. “An object like Arrokoth wouldn’t have formed, or look the way it does, in a more chaotic accretion environment.”

The latest Arrokoth reports significantly expand on the May 2019 Science paper, led by Stern. The three new papers are based on 10 times as much data as the first report, and together provide a far more complete picture of Arrokoth’s origin.

“All of the evidence we’ve found points to particle-cloud collapse models, and all but rule out hierarchical accretion for the formation mode of Arrokoth, and by inference, other planetesimals,” Stern said.

New Horizons continues to carry out new observations of additional Kuiper Belt objects it passes in the distance. New Horizons also continues to map the charged-particle radiation and dust environment in the Kuiper Belt. The new KBOs being observed now are too far away to reveal discoveries like those on Arrokoth, but the team can measure aspects such as each object's surface properties and shape. This summer the mission team will begin using large groundbased telescopes to search for new KBOs to study in this way, and even for another flyby target if fuel allows.

The New Horizons spacecraft is now 4.4 billion miles (7.1 billion kilometers) from Earth, operating normally and speeding deeper into the Kuiper Belt at nearly 31,300 miles (50,400 kilometers) per hour.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. The Marshall Space Flight Center Planetary Management Office provides the NASA oversight for the New Horizons. Southwest Research Institute, based in San Antonio, directs the mission via Principal Investigator Stern, and leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama.

Source: NASA.Gov


Wednesday, February 12, 2020

America's Next Red Planet Rover Has Arrived at Cape Canaveral in Florida!

A cargo container carrying NASA's Mars 2020 rover is loaded onto a C-17 aircraft at March Air Reserve Base in Riverside, California for the flight to Cape Canaveral, Florida...on February 11, 2020.
NASA / JPL - Caltech

NASA's Mars 2020 Rover Goes Coast-to-Coast to Prep for Launch (News Release)

The agency's first step in returning rocks from Mars just arrived at Kennedy Space Center. The Mars 2020 team now begins readying for a launch to the Red Planet this July.

NASA's next Mars rover has arrived in Florida to begin final preparations for its launch to the Red Planet this July. An Air Force C-17 Globemaster cargo plane carrying the Mars 2020 rover and descent stage touched down at NASA's Kennedy Space Center at about 3 p.m. EST (12 p.m. PST) today, completing a 2,300-mile (3,700-kilometer) trip that began yesterday at NASA's Jet Propulsion Laboratory near Pasadena, California. The mission's cruise stage and Mars Helicopter will make the trip to Kennedy later this week.

"Our rover has left the only home it has ever known," said John McNamee, Mars 2020 project manager. "The 2020 family here at JPL is a little sad to see it go, but we're even more proud knowing that the next time our rover takes to the skies, it will be headed to Mars."

Assembly, test and launch operations for Mars 2020 began in January 2018. The first piece of hardware that would become part of the rover arrived on the clean room floor of JPL's Spacecraft Assembly Facility's High Bay 1 a few months later.

The rover's aeroshell - its protective covering for the trip to the Red Planet - arrived at Kennedy this past December. Early on Feb. 11, the rover, cruise stage, descent stage and mission support equipment headed in four police-escorted trucks to the U.S. Air Force's March Air Reserve Base, where they were loaded aboard the two waiting C-17s.

Within hours of arriving at the Kennedy Space Center's Launch and Landing Facility, the Mars 2020 spacecraft components will be transported to the same spacecraft processing facility that in 2011 handled NASA's Curiosity rover, which is currently exploring Mars' Gale Crater. In the coming days, the Mars 2020 assembly, test and launch operations team will begin testing the components to assess their health following the cross-country flight.

After months of final assembly and additional testing, Mars 2020 should be enclosed in its aeroshell for the final time in late June. It will be delivered to Cape Canaveral Air Force Station's Launch Complex 41 to be integrated with the United Launch Alliance Atlas V rocket that will hurl it toward Jezero Crater in early July.

Mars 2020 will collect and store rock and soil samples in sealed tubes and will search for signs of past microbial life, characterize the planet's climate and geology, and pave the way for human exploration. Subsequent missions, currently in the planning stages, will return to Jezero Crater, gather the samples collected by Mars 2020 and return them to Earth for the sort of in-depth study that only a full-size lab can provide.

JPL is building and will manage operations of the Mars 2020 rover for NASA. NASA's Launch Services Program, based at the agency's Kennedy Space Center in Florida, is responsible for launch management.

Source: Jet Propulsion Laboratory

Tuesday, February 11, 2020

Our Communications Network for Interplanetary Spacecraft Is About to Get a New Addition in Southern California...

An artist's concept of the Deep Space Network's newest radio antenna: DSS-23...which has begun construction in California's Mojave Desert and will be completed in about 2.5 years.
NASA / JPL - Caltech

NASA Prepares for Moon and Mars With New Addition to Its Deep Space Network (News Release)

Robotic spacecraft will be able to communicate with the dish using radio waves and lasers.

Surrounded by California desert, NASA officials broke ground Tuesday, Feb. 11, on a new antenna for communicating with the agency's farthest-flung robotic spacecraft. Part of the Deep Space Network (DSN), the 112-foot-wide (34-meter-wide) antenna dish being built represents a future in which more missions will require advanced technology, such as lasers capable of transmitting vast amounts of data from astronauts on the Martian surface. As part of its Artemis program NASA will send the first woman and next man to the Moon by 2024, applying lessons learned there to send astronauts to Mars.

Using massive antenna dishes, the agency talks to more than 30 deep space missions on any given day, including many international missions. As more missions have launched and with more in the works, NASA is looking to strengthen the network. When completed in 2½ years, the new dish will be christened Deep Space Station-23 (DSS-23), bringing the DSN's number of operational antennas to 13.

"Since the 1960s, when the world first watched live pictures of humans in space and on the Moon, to revealing imagery and scientific data from the surface of Mars and vast, distant galaxies, the Deep Space Network has connected humankind with our solar system and beyond," said Badri Younes, NASA's deputy associate administrator for Space Communications and Navigation, or SCaN, which oversees NASA's networks. "This new antenna, the fifth of six currently planned, is another example of NASA's determination to enable science and space exploration through the use of the latest technology."

Managed by NASA's Jet Propulsion Laboratory in Pasadena, California, the world's largest and busiest deep space network is clustered in three locations - Goldstone, California; Madrid, Spain; and Canberra, Australia - that are positioned approximately 120 degrees apart around the globe to enable continual contact with spacecraft as the Earth rotates. (This live tool lets viewers see which DSN dishes are sending up commands or receiving data at any given time.)

The first addition to Goldstone since 2003, the new dish is being built at the complex's Apollo site, so named because its DSS-16 antenna supported NASA's human missions to the Moon. Similar antennas have been built in recent years in Canberra, while two are under construction in Madrid.

"The DSN is Earth's one phone line to our two Voyager spacecraft - both in interstellar space - all our Mars missions and the New Horizons spacecraft that is now far past Pluto," said JPL Deputy Director Larry James. "The more we explore, the more antennas we need to talk to all our missions."

While DSS-23 will function as a radio antenna, it will also be equipped with mirrors and a special receiver for lasers beamed from distant spacecraft. This technology is critical for sending astronauts to places like Mars. Humans there will need to communicate with Earth more than NASA's robotic explorers do, and a Mars base, with its life support systems and equipment, would buzz with data that needs to be monitored.

"Lasers can increase your data rate from Mars by about 10 times what you get from radio," said Suzanne Dodd, director of the Interplanetary Network, the organization that manages the DSN. "Our hope is that providing a platform for optical communications will encourage other space explorers to experiment with lasers on future missions."

While clouds can disrupt lasers, Goldstone's clear desert skies make it an ideal location to serve as a laser receiver about 60% of the time. A demonstration of DSS-23's capabilities is around the corner: When NASA launches an orbiter called Psyche to a metallic asteroid in a few years, it will carry an experimental laser communications terminal developed by JPL. Called the Deep Space Optical Communications project, this equipment will send data and images to an observatory at Southern California's Palomar Mountain. But Psyche will also be able to communicate with the new Goldstone antenna, paving the way for higher data rates in deep space.

Source: Jet Propulsion Laboratory

Sunday, January 26, 2020


As his wife and two daughters stand nearby, Kobe Bryant hoists up the NBA championship trophy after he leads the Los Angeles Lakers to its 15th title, on June 14, 2009.
Getty Images

Rest In Peace, Kobe. It was an honor meeting you at The Grove in Los Angeles back on October 23, 2018. It is totally surreal and heartbreaking that you are no longer with us. May you, your beautiful daughter Gianna, and the seven other wonderful people you were with when today's unthinkable tragedy took place now look down upon us from Heaven. We will surely continue to look up to you as a legend whose legacy will forever transcend the sport of basketball. Mamba out.

Posing with Kobe Bryant during a photo op inside Barnes & Noble bookstore at The Grove in Los Angeles...on October 23, 2018.

Monday, January 13, 2020

Photo of the Day: VIPER's Engineering Model Goes Through the Motions...

Two technicians look on as an engineering model of NASA's VIPER lunar rover is tested at NASA's Glenn Research Center in Cleveland, Ohio.
NASA / Bridget Caswell, Alcyon Technical Services

NASA’s New Moon Rover Tested in Lunar Operations Lab (News Release)

An engineering model of the Volatiles Investigating Polar Exploration Rover, or VIPER, is tested in the Simulated Lunar Operations Laboratory at NASA’s Glenn Research Center in Cleveland, Ohio. About the size of a golf cart, VIPER is a mobile robot that will roam around the Moon’s South Pole looking for water ice in the region and for the first time ever, actually sample the water ice at the same pole where the first woman and next man will land in 2024 under the Artemis program.

The large, adjustable soil bin contains lunar simulant and allows engineers to mimic the Moon’s terrain. Engineers from NASA’s Johnson Space Center in Houston, where the rover was designed and built, joined the Glenn team to complete the tests. Test data will be used to evaluate the traction of the vehicle and wheels, determine the power requirements for a variety of maneuvers and compare methods of traversing steep slopes. Respirators are worn by researchers to protect against the airborne silica that is present during testing.

VIPER is a collaboration within and beyond the agency. NASA's Ames Research Center in Silicon Valley is managing the project, leading the mission’s science, systems engineering, real-time rover surface operations and software. The rover’s instruments are provided by Ames, NASA’s Kennedy Space Center in Florida and commercial partner, Honeybee Robotics in California. The spacecraft, lander and launch vehicle that will deliver VIPER to the surface of the Moon will be provided through NASA’s Commercial Lunar Payload Services program, delivering science and technology payloads to and near the Moon.  

Source: NASA.Gov

Tuesday, January 07, 2020

TESS Update #2: Kepler's Successor Finds Its First Potentially-Habitable Exoplanet...

An artist's concept of three exoplanets orbiting within the TOI 700 star system.
NASA's Goddard Space Flight Center / Chris Smith

NASA Planet Hunter Finds its 1st Earth-size Habitable-zone World (News Release - January 6)

NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface. Scientists confirmed the find, called TOI 700 d, using NASA’s Spitzer Space Telescope and have modeled the planet’s potential environments to help inform future observations.

TOI 700 d is one of only a few Earth-size planets discovered in a star's habitable zone so far. Others include several planets in the TRAPPIST-1 system and other worlds discovered by NASA’s Kepler Space Telescope.

“TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars,” said Paul Hertz, astrophysics division director at NASA Headquarters in Washington. “Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS. Confirming the planet’s size and habitable zone status with Spitzer is another win for Spitzer as it approaches the end of science operations this January."

TESS monitors large swaths of the sky, called sectors, for 27 days at a time. This long stare allows the satellite to track changes in stellar brightness caused by an orbiting planet crossing in front of its star from our perspective, an event called a transit.

TOI 700 is a small, cool M dwarf star located just over 100 light-years away in the southern constellation Dorado. It’s roughly 40% of the Sun’s mass and size and about half its surface temperature. The star appears in 11 of the 13 sectors TESS observed during the mission’s first year, and scientists caught multiple transits by its three planets.

The star was originally misclassified in the TESS database as being more similar to our Sun, which meant the planets appeared larger and hotter than they really are. Several researchers, including Alton Spencer, a high school student working with members of the TESS team, identified the error.

“When we corrected the star’s parameters, the sizes of its planets dropped, and we realized the outermost one was about the size of Earth and in the habitable zone,” said Emily Gilbert, a graduate student at the University of Chicago. “Additionally, in 11 months of data we saw no flares from the star, which improves the chances TOI 700 d is habitable and makes it easier to model its atmospheric and surface conditions.”

Gilbert and other researchers presented the findings at the 235th meeting of the American Astronomical Society in Honolulu, and three papers — one of which Gilbert led — have been submitted to scientific journals.

The innermost planet, called TOI 700 b, is almost exactly Earth-size, is probably rocky and completes an orbit every 10 days. The middle planet, TOI 700 c, is 2.6 times larger than Earth — between the sizes of Earth and Neptune — orbits every 16 days and is likely a gas-dominated world. TOI 700 d, the outermost known planet in the system and the only one in the habitable zone, measures 20% larger than Earth, orbits every 37 days and receives from its star 86% of the energy that the Sun provides to Earth. All of the planets are thought to be tidally locked to their star, which means they rotate once per orbit so that one side is constantly bathed in daylight.

A team of scientists led by Joseph Rodriguez, an astronomer at the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, requested follow-up observations with Spitzer to confirm TOI 700 d.

“Given the impact of this discovery — that it is TESS’s first habitable-zone Earth-size planet — we really wanted our understanding of this system to be as concrete as possible,” Rodriguez said. “Spitzer saw TOI 700 d transit exactly when we expected it to. It’s a great addition to the legacy of a mission that helped confirm two of the TRAPPIST-1 planets and identify five more.”

The Spitzer data increased scientists’ confidence that TOI 700 d is a real planet and sharpened their measurements of its orbital period by 56% and its size by 38%. It also ruled out other possible astrophysical causes of the transit signal, such as the presence of a smaller, dimmer companion star in the system.

Rodriguez and his colleagues also used follow-up observations from a 1-meter ground-based telescope in the global Las Cumbres Observatory network to improve scientists’ confidence in the orbital period and size of TOI 700 c by 30% and 36%, respectively.

Because TOI 700 is bright, nearby, and shows no sign of stellar flares, the system is a prime candidate for precise mass measurements by current ground-based observatories. These measurements could confirm scientists’ estimates that the inner and outer planets are rocky and the middle planet is made of gas.

Future missions may be able to identify whether the planets have atmospheres and, if so, even determine their compositions.

While the exact conditions on TOI 700 d are unknown, scientists can use current information, like the planet’s size and the type of star it orbits, to generate computer models and make predictions. Researchers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, modeled 20 potential environments of TOI 700 d to gauge if any version would result in surface temperatures and pressures suitable for habitability.

Their 3D climate models examined a variety of surface types and atmospheric compositions typically associated with what scientists regard to be potentially habitable worlds. Because TOI 700 d is tidally locked to its star, the planet’s cloud formations and wind patterns may be strikingly different from Earth’s.

One simulation included an ocean-covered TOI 700 d with a dense, carbon-dioxide-dominated atmosphere similar to what scientists suspect surrounded Mars when it was young. The model atmosphere contains a deep layer of clouds on the star-facing side. Another model depicts TOI 700 d as a cloudless, all-land version of modern Earth, where winds flow away from the night side of the planet and converge on the point directly facing the star.

When starlight passes through a planet’s atmosphere, it interacts with molecules like carbon dioxide and nitrogen to produce distinct signals, called spectral lines. The modeling team, led by Gabrielle Engelmann-Suissa, a Universities Space Research Association visiting research assistant at Goddard, produced simulated spectra for the 20 modeled versions of TOI 700 d.

“Someday, when we have real spectra from TOI 700 d, we can backtrack, match them to the closest simulated spectrum, and then match that to a model,” Engelmann-Suissa said. “It’s exciting because no matter what we find out about the planet, it’s going to look completely different from what we have here on Earth.”

TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space Flight Center. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

The modeling work was funded through the Sellers Exoplanet Environments Collaboration at Goddard, a multidisciplinary collaboration that brings together experts to build comprehensive and sophisticated computer models to better analyze current and future exoplanet observations.

Source: NASA.Gov


Monday, January 06, 2020

TESS Update: 2020 Begins with an Amazing Discovery Made by Kepler's Successor...

An artist's concept of the exoplanet TOI 1338 b orbiting its two parent stars.
NASA's Goddard Space Flight Center / Chris Smith

NASA’s TESS Mission Uncovers Its 1st World With Two Stars (News Release)

In 2019, when Wolf Cukier finished his junior year at Scarsdale High School in New York, he joined NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as a summer intern. His job was to examine variations in star brightness captured by NASA’s Transiting Exoplanet Survey Satellite (TESS) and uploaded to the Planet Hunters TESS citizen science project.

“I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit,” Cukier said. “About three days into my internship, I saw a signal from a system called TOI 1338. At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet.”

TOI 1338 b, as it is now called, is TESS’s first circumbinary planet, a world orbiting two stars. The discovery was featured in a panel discussion on Monday, Jan. 6, at the 235th American Astronomical Society meeting in Honolulu. A paper, which Cukier co-authored along with scientists from Goddard, San Diego State University, the University of Chicago and other institutions, has been submitted to a scientific journal.

The TOI 1338 system lies 1,300 light-years away in the constellation Pictor. The two stars orbit each other every 15 days. One is about 10% more massive than our Sun, while the other is cooler, dimmer and only one-third the Sun’s mass.

TOI 1338 b is the only known planet in the system. It’s around 6.9 times larger than Earth, or between the sizes of Neptune and Saturn. The planet orbits in almost exactly the same plane as the stars, so it experiences regular stellar eclipses.

TESS has four cameras, which each take a full-frame image of a patch of the sky every 30 minutes for 27 days. Scientists use the observations to generate graphs of how the brightness of stars change over time. When a planet crosses in front of its star from our perspective, an event called a transit, its passage causes a distinct dip in the star’s brightness.

But planets orbiting two stars are more difficult to detect than those orbiting one. TOI 1338 b’s transits are irregular, between every 93 and 95 days, and vary in depth and duration thanks to the orbital motion of its stars. TESS only sees the transits crossing the larger star; the transits of the smaller star are too faint to detect.

“These are the types of signals that algorithms really struggle with,” said lead author Veselin Kostov, a research scientist at the SETI Institute and Goddard. “The human eye is extremely good at finding patterns in data, especially non-periodic patterns like those we see in transits from these systems.”

This explains why Cukier had to visually examine each potential transit. For example, he initially thought TOI 1338 b’s transit was a result of the smaller star in the system passing in front of the larger one — both cause similar dips in brightness. But the timing was wrong for an eclipse.

After identifying TOI 1338 b, the research team used a software package called eleanor, named after Eleanor Arroway, the central character in Carl Sagan’s novel “Contact,” to confirm the transits were real and not a result of instrumental artifacts.

“Throughout all of its images, TESS is monitoring millions of stars,” said co-author Adina Feinstein, a graduate student at the University of Chicago. “That’s why our team created eleanor. It’s an accessible way to download, analyze and visualize transit data. We designed it with planets in mind, but other members of the community use it to study stars, asteroids and even galaxies.”

TOI 1338 had already been studied from the ground by radial velocity surveys, which measure motion along our line of sight. Kostov’s team used this archival data to analyze the system and confirm the planet. Its orbit is stable for at least the next 10 million years. The orbit’s angle to us, however, changes enough that the planet transit will cease after November 2023 and resume eight years later.

NASA’s Kepler and K2 missions previously discovered 12 circumbinary planets in 10 systems, all similar to TOI 1338 b. Observations of binary systems are biased toward finding larger planets, Kostov said. Transits of smaller bodies don’t have as big an effect on the stars’ brightness. TESS is expected to observe hundreds of thousands of eclipsing binaries during its initial two-year mission, so many more of these circumbinary planets should be waiting for discovery.

TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space Flight Center. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.​

Source: NASA.Gov