mercredi 15 juillet 2020

'Disk Detective' Needs Your Help Finding Disks Where Planets Form












NASA - NEOWISE Mission logo.

July 15, 2020

Members of the public can help scientists learn how planets form by sifting through data from NASA's WISE mission, managed by the agency's Jet Propulsion Laboratory.

Planets form from gas and dust particles swirling around baby stars in enormous spinning disks. But because this process takes millions of years, scientists can only learn about these disks by finding and studying a lot of different examples.


Image above: This illustration shows a young, Sun-like star encircled by its planet-forming disk of gas and dust. Image Credits: NASA/JPL-Caltech.

Through a project called Disk Detective, you can help. Anyone, regardless of background or prior knowledge, can assist scientists in figuring out the mysteries of planet formation. Disk Detective is an example of citizen science, a collaboration between professional scientists and members of the public.

"We're trying to understand how long it takes for planets to form," said astrophysicist Marc Kuchner, the Disk Detective project lead at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the Citizen Science Officer for NASA's Science Mission Directorate. "Tracing the evolution of these disks is the main way that we know how long planet formation takes."

Disk Detective has just relaunched with a new website and a new dataset of about 150,000 stars. This new version of the project focuses on M dwarfs, which represent the most common type of star in the Milky Way galaxy. It also concentrates on brown dwarfs, which are balls of gas that don't burn hydrogen the way stars do and often more closely resemble giant planets like Jupiter.

After reading the instructions, participants can start identifying disks right away in Disk Detective. The interface presents a series of real astronomical images and asks visitors questions that will help determine more definitively if a disk is present. The images come from NASA's Wide-Field Infrared Survey Explorer (WISE), which now operates as NEOWISE, as well as the ground-based Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) in Hawaii and the NASA-funded Two Micron All-Sky Survey (2MASS), which operated from 1997 to 2001.

"We have multiple citizen scientists look at each object, give their own independent opinion, and trust the wisdom of the crowd to decide what things are probably galaxies and what things are probably stars with disks around them," said Disk Detective's director, Steven Silverberg, a postdoctoral researcher at Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research.


Animation above: Planets form from gas and dust particles swirling around baby stars in enormous spinning disks. Animation Credits: NASA/JPL-Caltech.

Advanced users learn more about the objects they're studying using professional data archives. Those who contribute substantial insight receive credit on scientific papers describing the discoveries made through Disk Detective's efforts. Professional scientists then follow up on citizen scientists' input using more sophisticated tools and new observations. Fifteen citizen scientists have already become named co-authors on peer-reviewed scientific papers through Disk Detective.

One enthusiastic Disk Detective "superuser" is Hugo Durantini Luca, a computer technician in Córdoba, Argentina. He began classifying disks with the project in 2014 and since then has taken on additional responsibilities: writing tutorials, moderating discussions, and even helping use telescopes in South America to follow up on interesting targets. While he became involved because of his interest in detecting planetary systems and analyzing images, he says he highly values "the way you are able to work with the science team directly." He is in frequent communication with Kuchner and other professional astronomers, and he participates in a weekly video call for superusers.

Wide-Field Infrared Survey Explorer (WISE). Image Credit: NASA

"I think we are going to have an interesting new season," Durantini Luca said. "The new way we are processing the data will allow us to analyze the image[s] with better detail."

Citizen scientists at Disk Detective made an important discovery in 2016: a new class of disks, called Peter Pan disks. Most disks around young, low-mass stars should lose their gas, due to planet formation and natural dissipation into space, after 5 million years. Yet Disk Detective citizen scientists discovered a disk with plenty of gas orbiting a star that is roughly 45 million years old.

Since then, seven similar mysteriously young-looking disks have been found, each at least 20 million years old. Scientists are still puzzling out why planet formation goes on for so long in these disks. They predict that citizen scientists may find as many as 15 new Peter Pan disks through the newly revamped Disk Detective.

"To figure out how disks evolve, we need a big sample of different kinds of disks of different ages," Kuchner said.

Disks Where Planets Form. Animation Credit: NASA

More recently, Disk Detective's efforts resulted in a discovery announced on June 2 at the American Astronomical Society's (AAS) 236th meeting, which was held virtually. With the help of citizen scientists, astronomers identified the closest young brown dwarf disk yet, one that may have the capability to form planets. This 3.7-million-year-old brown dwarf, called W1200-7845, is about 333 light-years away. A light-year is the distance light travels in one year; the closest star beyond the Sun is over 4 light-years away.

"There are not many examples of young brown dwarfs so close to the Sun, so W1200-7845 is an exciting discovery," said Maria Schutte, a predoctoral graduate student at the University of Oklahoma, who led the study and presented the findings at the AAS meeting. Durantini Luca and other citizen scientists were included as coauthors.

Since the last Disk Detective data release, ESA's (European Space Agency's) Gaia satellite has delivered an unprecedented bounty of information about the locations, movements, and types of stars in the Milky Way. The Disk Detective science team used the new data from Gaia to identify M dwarfs of interest to the project. A second improvement to the project is that the new images from the surveys listed above have higher resolution than the previous batch of data, making more background objects visible.

"NASA needs your help," Kuchner said. "Come discover these disks with us!"

About Disk Detective

Disk Detective is a NASA-funded citizen science project that is part of the NASA-sponsored Zooniverse citizen science platform.

Check out the revamped Disk Detective project at:

https://diskdetective.org

Learn more about NASA Citizen Science at:

https://science.nasa.gov/citizenscience

About WISE and NEOWISE

NASA's Jet Propulsion Laboratory in Southern California managed and operated WISE for NASA's Science Mission Directorate from 2009 to 2011. Edward Wright at the University of California, Los Angeles was the principal investigator. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Maryland. In late 2013, the spacecraft was reactivated and renamed NEOWISE.

For more information about NEOWISE, visit:

https://www.nasa.gov/neowise

http://neowise.ipac.caltech.edu/

For more information about WISE, visit:

http://www.nasa.gov/wise

https://www.jpl.nasa.gov/wise/

Images (mentioned), Animations (mentioned), Text, Credits: NASA/Elizabeth Landau/JPL/Calla Cofield.

Greetings, Orbiter.ch

mardi 14 juillet 2020

Busy Day of Spacewalk Preps and Human Research













ISS - Expedition 63 Mission patch.

July 14, 2020

Two astronauts are concentrating on the final set of power upgrade spacewalks on the International Space Station beginning this week. Meanwhile, their Expedition 63 crewmates continued focusing on biology research to ensure humans stay healthy in space during long-term missions.

Flight Engineer Bob Behnken and Commander Chris Cassidy for preparing for a pair of spacewalks to wrap up battery swaps and ready the orbiting lab for a new airlock. The duo collected and organized spacewalk tools then studied their tasks step-by-step on a computer during the afternoon. Fellow NASA astronaut Doug Hurley assisted the pair and installed their spacesuit batteries and metal oxide canisters to remove carbon dioxide from the suit.


Image above: This starry nighttime shot of Rio de Janeiro and surrounding cities on the Brazilian coast was taken as the space station orbited above São Paolo before going over the Atlantic Ocean. Image Credit: NASA.

Behnken and Cassidy will exit the station for the first spacewalk on Thursday. The spacewalk is scheduled to begin at 7:35 a.m. EDT. The spacewalkers will spend about seven hours removing aging nickel-hydrogen batteries and replacing them with new lithium-ion batteries on the Starboard-3 truss structure. NASA TV begins its live coverage at 6 a.m.

The second spacewalk is scheduled to start at the same time on Tuesday, July 21, for the final battery swaps to complete 3.5 years of external power upgrades on the space station. Behnken and Cassidy will then begin outfitting the Tranquility module for a new commercial airlock from NanoRacks. The airlock, designed to deploy public and private experiments, will be installed to Tranquility after its delivery later this year aboard the SpaceX Dragon cargo vehicle.

Astronaut spacewalk at ISS. Animation Credit: NASA

Meanwhile, a host of space science continues aboard the orbiting lab including human research to maintain healthy crews. NASA and its international partners are studying how the human body adapts to microgravity as they plan longer missions farther out into space.

The two cosmonauts from Roscosmos, Anatoly Ivanishin and Ivan Vagner, were once again exploring ways to stave off the negative effects of living in space. Vagner continued logging his meals and drinks and collected a blood sample for a study that seeks to reverse the loss of bone mass caused by microgravity. He later collected his saliva sample and attached a sensor to himself for an immune system investigation. Ivanishin exercised on a treadmill for a physical fitness evaluation and spent the rest of the day on communications and ventilation maintenance.

Related article:

NASA Broadcasts Final Spacewalks to Upgrade Space Station Power System
https://orbiterchspacenews.blogspot.com/2020/07/nasa-broadcasts-final-spacewalks-to.html

Related links:

Expedition 63: https://www.nasa.gov/mission_pages/station/expeditions/expedition63/index.html

Commercial Crew Program: https://www.nasa.gov/exploration/commercial/crew/index.html

ISS Starboard-3 truss structure: https://www.nasa.gov/mission_pages/station/structure/elements/truss-structure

Tranquility module: https://www.nasa.gov/mission_pages/station/structure/elements/tranquility/

Loss of bone mass: https://www.energia.ru/en/iss/researches/human/21.html

Immune system: https://www.energia.ru/en/iss/researches/human/22.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/overview.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

6 Things to Know About NASA's Ingenuity Mars Helicopter













NASA - Mars 2020 Perseverance Rover logo.

July 14, 2020

The first helicopter attempting to fly on another planet is a marvel of engineering. Get up to speed with these key facts about its plans.

When NASA's Mars 2020 Perseverance rover launches from Cape Canaveral Air Force Station in Florida later this summer, an innovative experiment will ride along: the Ingenuity Mars Helicopter. Ingenuity may weigh only about 4 pounds (1.8 kilograms), but it has some outsize ambitions.


Image above: In this illustration, NASA's Ingenuity Mars Helicopter stands on the Red Planet's surface as NASA's Perseverance rover (partially visible on the left) rolls away. Image Credits: NASA/JPL-Caltech.

"The Wright Brothers showed that powered flight in Earth's atmosphere was possible, using an experimental aircraft," said Håvard Grip, Ingenuity’s chief pilot at NASA's Jet Propulsion Laboratory in Southern California. "With Ingenuity, we're trying to do the same for Mars."

Here are six things you should know about the first helicopter going to another planet:

1. Ingenuity is a flight test.

Ingenuity is what is known as a technology demonstration – a project that seeks to test a new capability for the first time, with limited scope. Previous groundbreaking technology demonstrations include the Mars Pathfinder rover Sojourner and the tiny Mars Cube One (MarCO) CubeSats that flew by Mars in 2018.

Ingenuity features four specially made carbon-fiber blades, arranged into two rotors that spin in opposite directions at around 2,400 rpm – many times faster than a passenger helicopter on Earth. It also has innovative solar cells, batteries, and other components. Ingenuity doesn't carry science instruments and is a separate experiment from the Mars 2020 Perseverance rover.

2. Ingenuity will be the first aircraft to attempt controlled flight on another planet. 
 
NASA’s Ingenuity Mars Helicopter: Attempting the First Powered Flight on Mars

Video above: NASA's Ingenuity Mars Helicopter will make history's first attempt at powered flight on another planet next spring. It is riding with the agency's next mission to Mars (the Mars 2020 Perseverance rover) as it launches from Cape Canaveral Air Force Station later this summer. Perseverance, with Ingenuity attached to its belly, will land on Mars February 18, 2021. Video Credits: NASA/JPL-Caltech.

What makes it hard for a helicopter to fly on Mars? For one thing, Mars' thin atmosphere makes it difficult to achieve enough lift. Because the Mars atmosphere is 99% less dense than Earth's, Ingenuity has to be light, with rotor blades that are much larger and spin much faster than what would be required for a helicopter of Ingenuity's mass on Earth.

It can also be bone-chillingly cold at Jezero Crater, where Perseverance will land with Ingenuity attached to its belly in February 2021. Nights there dip down to minus 130 degrees Fahrenheit (minus 90 degrees Celsius). While Ingenuity's team on Earth has tested the helicopter at Martian temperatures and believes it should work on Mars as intended, the cold will push the design limits of many of Ingenuity's parts.

In addition, flight controllers at JPL won't be able to control the helicopter with a joystick. Communication delays are an inherent part of working with spacecraft across interplanetary distances. Commands will need to be sent well in advance, with engineering data coming back from the spacecraft long after each flight takes place. In the meantime, Ingenuity will have a lot of autonomy to make its own decisions about how to fly to a waypoint and keep itself warm.

3. Ingenuity is a fitting name for a robot that is the result of extreme creativity.

High school student Vaneeza Rupani of Northport, Alabama, originally submitted the name Ingenuity for the Mars 2020 rover, before it was named Perseverance, but NASA officials recognized the submission as a terrific name for the helicopter, given how much creative thinking the team employed to get the mission off the ground.

"The ingenuity and brilliance of people working hard to overcome the challenges of interplanetary travel are what allow us all to experience the wonders of space exploration," Rupani wrote. "Ingenuity is what allows people to accomplish amazing things."

NASA's Mars 2020 Perseverance rover and NASA's Ingenuity Mars Helicopter (shown in an artist's concept).


Image above: In February 2021, NASA's Mars 2020 Perseverance rover and NASA's Ingenuity Mars Helicopter (shown in an artist's concept) will be the agency's two newest explorers on Mars. Both were named by students as part of an essay contest. Image Credits: NASA/JPL-Caltech.

4. Ingenuity has already demonstrated feats of engineering.

In careful steps from 2014 to 2019, engineers at JPL demonstrated that it was possible to build an aircraft that was lightweight, able to generate enough lift in Mars' thin atmosphere, and capable of surviving in a Mars-like environment. They tested progressively more advanced models in special space simulators at JPL. In January 2019, the actual helicopter that is riding with Perseverance to the Red Planet passed its final flight evaluation. Failing any one of these milestones would've grounded the experiment.

5. The Ingenuity team will count success one step at a time.

Given the firsts Ingenuity is trying to accomplish, the team has a long list of milestones they'll need to pass before the helicopter can take off and land in the spring of 2021. The team will celebrate each time they meet one. The milestones include:

    - Surviving the launch from Cape Canaveral, the cruise to Mars, and landing on the Red Planet
    - Safely deploying to the surface from Perseverance's belly
    - Autonomously keeping warm through the intensely cold Martian nights
    - Autonomously charging itself with its solar panel

And then Ingenuity will make its first flight attempt. If the helicopter succeeds in that first flight, the Ingenuity team will attempt up to four other test flights within a 30-Martian-day (31-Earth-day) window.

6. If Ingenuity succeeds, future Mars exploration could include an ambitious aerial dimension.


Image above: When NASA's Ingenuity Mars Helicopter attempts its first test flight on the Red Planet, the agency's Mars 2020 Perseverance rover will be close by, as seen in this artist's concept. Image Credits: NASA/JPL-Caltech.

Ingenuity is intended to demonstrate technologies needed for flying in the Martian atmosphere. If successful, these technologies could enable other advanced robotic flying vehicles that might be included in future robotic and human missions to Mars. They could offer a unique viewpoint not provided by current orbiters high overhead or by rovers and landers on the ground, provide high-definition images and reconnaissance for robots or humans, and enable access to terrain that is difficult for rovers to reach.

"The Ingenuity team has done everything to test the helicopter on Earth, and we are looking forward to flying our experiment in the real environment at Mars," said MiMi Aung, Ingenuity’s project manager at JPL. "We'll be learning all along the way, and it will be the ultimate reward for our team to be able to add another dimension to the way we explore other worlds in the future."


Image above: An artist's concept of NASA's Ingenuity Mars Helicopter flying through the Red Planet's skies. Image Credits: NASA/JPL-Caltech.

Related article:

7 Things to Know About the Mars 2020 Perseverance Rover Mission
https://orbiterchspacenews.blogspot.com/2020/07/7-things-to-know-about-mars-2020.html

Related links:

Mars Pathfinder rover: https://mars.nasa.gov/mars-exploration/missions/pathfinder/

Mars Cube One (MarCO): https://www.jpl.nasa.gov/cubesat/missions/marco.php

Mars Perseverance Rover: http://www.nasa.gov/perseverance

For more information about Ingenuity, check out the press kit for the Perseverance launch:

https://go.nasa.gov/perseverance-launch-press-kit

More information is also available on Ingenuity's web page:

https://mars.nasa.gov/technology/helicopter

Images (mentioned), Video (mentioned), Text, Credits: NASA/Tony Greicius/Grey Hautaluoma/Alana Johnson/JPL/Jia-Rui Cook.

Greetings, Orbiter.ch

lundi 13 juillet 2020

Spacewalk Preps, Satellite Deployment During Bone and Heart Research













ISS - Expedition 63 Mission patch.

July 13, 2020

Two NASA astronauts are setting their sights on the final pair of spacewalks to continue upgrading power systems on the International Space Station. The orbiting lab also deployed a pair of microsatellites today while the rest of the Expedition 63 crew explored how weightlessness affects the human body.

Flight Engineer Bob Behnken will lead the next two spacewalks to install new lithium-ion (Li-Ion) batteries on the station’s starboard truss structure starting at 7:35 a.m. EDT on Thursday, July 16, and Tuesday, July 21. He will be joined by Commander Chris Cassidy for the two six-and-a-half-hour spacewalks that will finalize the swap of aging nickel-hydrogen batteries with the Li-Ion batteries.


Image above: The southern tip of Brazil (upper left) bordering Uruguay was pictured as the International Space Station orbited off the Atlantic coast of South America. Image Credit: NASA.

The veteran spacewalkers spent a couple of hours today reviewing their spacewalk procedures step-by-step on a computer. They were joined afterward by Flight Engineer Doug Hurley for a conference with spacewalk specialists in Mission Control. Hurley also began charging the batteries that will power the U.S. spacesuits for the duration of Behnken’s and Cassidy’s spacewalk.

A pair of microsatellites were deployed into Earth orbit today outside Japan’s Kibo laboratory module. The Deformable Mirror CubeSat will demonstrate the performance of a tiny but powerful exo-planet telescope. The TechEdSat-10 CubeSat will test returning small payloads safely into Earth’s atmosphere.

Kibo laboratory module on ISS. Image Credit: NASA

On the Russian side of the station, the two cosmonauts focused on human biology as they conducted a hearing test and studied how diet and exercise can fight the negative effects of microgravity.

Cosmonaut Ivan Vagner, on his first space mission, documented his meals and drinks today to help doctors learn how to counteract the loss of bone mass that occurs during long-term spaceflight. He also joined three-time station resident Anatoly Ivanishin attaching sensors to themselves to monitor their cardiovascular system while working out on an exercise bike. The duo wrapped up the day wearing headphones plugged into a computer that exposed the cosmonauts to a variety of frequencies for a hearing test.

Related article:

NASA Broadcasts Final Spacewalks to Upgrade Space Station Power System
https://orbiterchspacenews.blogspot.com/2020/07/nasa-broadcasts-final-spacewalks-to.html

Related links:

Expedition 63: https://www.nasa.gov/mission_pages/station/expeditions/expedition63/index.html

Commercial Crew Program: https://www.nasa.gov/exploration/commercial/crew/index.html

Station’s starboard truss structure: https://www.nasa.gov/mission_pages/station/structure/elements/truss-structure

Kibo laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory

Deformable Mirror CubeSat: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=8053

TechEdSat-10 CubeSat: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=8124

Loss of bone mass: https://www.energia.ru/en/iss/researches/human/21.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/overview.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

NASA Broadcasts Final Spacewalks to Upgrade Space Station Power System













EVA - Extra Vehicular Activities patch.

July 13, 2020

NASA astronauts Chris Cassidy and Robert Behnken will conduct a pair of spacewalks Thursday, July 16, and Tuesday, July 21, to finish a 3.5-year effort to upgrade the International Space Station’s power system.

Coverage each day will begin at 6 a.m. EDT (10 a.m. GMT) on NASA Television and the agency’s website. The spacewalks will begin around 7:35 a.m. (11.35 a.m. GMT) and could last up to seven hours.

Cassidy and Behnken will replace aging nickel-hydrogen batteries with new lithium-ion batteries delivered to the station on a Japanese cargo ship in May. The replacements will be on the starboard 6 truss’ 3B power channel.


Image above: NASA astronaut Bob Behnken (at left) is pictured during a spacewalk to swap batteries and upgrade power systems on the International Space Station's Starboard-6 truss structure. Pictured at lower right, is an external pallet, gripped by the Canadarm2 robotic arm, that housed the batteries replaced on the orbiting lab. Behnken was joined during the six-hour and seven-minute excursion by NASA astronaut Chris Cassidy (out of frame). Image Credit: NASA.

During the July 16 spacewalk, they plan to remove five of six older nickel-hydrogen batteries for the truss’ power system and install three new lithium-ion batteries, as well as accompanying hardware. The last nickel-hydrogen battery will be removed from the truss and stowed on July 21, when Behnken and Cassidy venture out on the 300th spacewalk involving U.S. astronauts since Ed White stepped out of his Gemini 4 capsule on June 3, 1965.

In all, 12 spacewalks will have been performed since January 2017 to change out batteries for eight power channels used to route electricity on the station.

When the power upgrades are complete, the astronauts will shift gears and remove two lifting fixtures used for ground processing of the station’s solar arrays prior to their launch. They’ll also begin preparing the Tranquility module for the installation of a commercial airlock provided by NanoRacks and scheduled to arrive on a SpaceX cargo flight later this year. The airlock will be used to deploy commercial and government-sponsored experiments into space.

Maintenance Spacewalk. Animation Credit: NASA

Behnken will be designated extravehicular crewmember 1 for both spacewalks and wear a spacesuit bearing red stripes. Cassidy will be extravehicular crewmember 2 for both spacewalks, wearing a suit with no stripes.

These will be the 230th and 231st spacewalks in the history of space station assembly, maintenance, and upgrades. They also will be the ninth and 10th for Cassidy and Behnken, who will join former NASA astronauts Michael Lopez-Alegria and Peggy Whitson with the most spacewalks by Americans.

Cassidy arrived at the space station in April, taking command of Expedition 63. Behnken, who is serving as a flight engineer for the expedition, arrived at the station in May with fellow Commercial Crew astronaut Douglas Hurley on SpaceX’s Crew Dragon Demo-2 test flight.

For almost 20 years, humans have lived and worked continuously aboard the International Space Station, advancing scientific knowledge and demonstrating new technologies, making research breakthroughs not possible on Earth that will enable long-duration human and robotic exploration into deep space. As a global endeavor, 239 people from 19 countries have visited the unique microgravity laboratory that has hosted more than 2,800 research investigations from researchers in 108 countries and areas.

Related links:

NASA Television: https://www.nasa.gov/live

Expedition 63: https://www.nasa.gov/mission_pages/station/expeditions/expedition63/index.html

Spacewalks: https://www.nasa.gov/mission_pages/station/spacewalks/

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

NASA/Sean Potter/Stephanie Schierholz/JSC/Courtney Beasley.

Hubble Sees a Star Called HBC 672 and the Bat Shadow











NASA - Hubble Space Telescope patch.

July 13, 2020


Astronomers using a previously captured Hubble imagery spotted a remarkable image of a young star's unseen, planet-forming disk casting a huge shadow across a more distant cloud in a star-forming region. The star is called HBC 672, and the shadow feature was nicknamed the "Bat Shadow" because it resembles a pair of wings. The nickname turned out to be unexpectedly appropriate, because now those "wings" appear to be flapping!

Hubble Space Telescope (HST)

For more information about Hubble, visit:

http://hubblesite.org/

http://www.nasa.gov/hubble

http://www.spacetelescope.org/

Image, Animation Credits: NASA, Yvette Smith, ESA, and STScI.

Greetings, Orbiter.ch

dimanche 12 juillet 2020

Two Bizarre Brown Dwarfs Found With Citizen Scientists' Help















NASA logo / NASA-funded Backyard Worlds: Planet 9 logo.

July 12, 2020

Data from NASA's NEOWISE mission, managed by the agency's Jet Propulsion Laboratory, fuels the search for these not-quite-planets-but-not-quite-stars.

With the help of citizen scientists, astronomers have discovered two highly unusual brown dwarfs, balls of gas that are not massive enough to power themselves the way stars do.


Image above: This artist's concept shows a brown dwarf, a ball of gas not massive enough to power itself the way stars do. Despite their name, brown dwarfs would appear magenta or orange-red to the human eye if seen close up. Image Credit: William Pendrill (CC BY).

Participants in the NASA-funded Backyard Worlds: Planet 9 project helped lead scientists to these bizarre objects, using data from NASA's Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) satellite along with all-sky observations collected between 2009 and 2011 under its previous moniker, WISE. Backyard Worlds: Planet 9 is an example of "citizen science," a collaboration between professional scientists and members of the public.

Scientists call the newly discovered objects "the first extreme T-type subdwarfs." They weigh about 75 times the mass of Jupiter and clock in at roughly 10 billion years old. These two objects are the most planetlike brown dwarfs yet seen among the Milky Way's oldest population of stars.


Image above: These images show the newly discovered brown dwarf WISE 1810 as seen with the WiseView tool. The object has an orange hue in these false-color images. In both images, a gray arrow on the left indicates the object's position in 2010; the black arrow on the right indicates its position in 2016. Image Credits: Schneider et al. 2020.

Astronomers hope to use these brown dwarfs to learn more about exoplanets, which are planets outside our solar system. The same physical processes may form both planets and brown dwarfs.

"These surprising, weird brown dwarfs resemble ancient exoplanets closely enough that they will help us understand the physics of the exoplanets," said astrophysicist Marc Kuchner, the principal investigator of Backyard Worlds: Planet 9 and the Citizen Science Officer for NASA's Science Mission Directorate. Kuchner is also an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

These two special brown dwarfs have highly unusual compositions. When viewed in particular wavelengths of infrared light, they look like other brown dwarfs, but at others they do not resemble any other stars or planets that have been observed so far.

Scientists were surprised to see they have very little iron, meaning that, like ancient stars, they have not incorporated iron from star births and deaths in their environments. A typical brown dwarf would have as much as 30 times more iron and other metals than these newly discovered objects. One of these brown dwarfs seems to have only about 3% as much iron as our Sun. Scientists expect very old exoplanets would have a low metal content, too.

"A central question in the study of brown dwarfs and exoplanets is how much does planet formation depend on the presence of metals like iron and other elements formed by multiple earlier generations of stars," Kuchner said. "The fact that these brown dwarfs seem to have formed with such low metal abundances suggests that maybe we should be searching harder for ancient, metal-poor exoplanets, or exoplanets orbiting ancient, metal-poor stars."

A study in The Astrophysical Journal details these discoveries and the potential implications. Six citizen scientists are listed as coauthors of the study.

How Volunteers Found These Extreme Brown Dwarfs

The study's lead author, Adam Schneider of Arizona State University's School of Earth and Space Exploration in Tempe, first noticed one of the unusual brown dwarfs, called WISE 1810, in 2016, but it was in a crowded area of the sky and was difficult to confirm.

With the help of a tool called WiseView, created by Backyard Worlds: Planet 9 citizen scientist Dan Caselden, Schneider confirmed that the object he had seen years earlier was moving quickly, which is a good indication that an object is a nearby celestial body like a planet or brown dwarf.

"WiseView scrolls through data like a short movie," Schneider said, "so you can see more easily see if something is moving or not."

The second unusual brown dwarf, WISE 0414, was discovered by a group of citizen scientists, including Backyard Worlds participants Paul Beaulieu, Sam Goodman, William Pendrill, Austin Rothermich, and Arttu Sainio.

The citizen scientists who found WISE 0414 combed through hundreds of images taken by WISE looking for moving objects, which are best detected with the human eye.

"The discovery of these two brown dwarfs shows that science enthusiasts can contribute to the scientific process," Schneider said. "Through Backyard Worlds, thousands of people can work together to find unusual objects in the solar neighborhood."

Astronomers followed up to determine their physical properties and confirm that they are indeed brown dwarfs. The discovery of these two unusual brown dwarfs suggests astronomers may be able to find more of these objects in the future.

The new study is coauthored by Federico Marocco, an astrophysicist at IPAC at Caltech in Pasadena, California, who conducted the work while at JPL. Marocco and JPL astronomer Eric Mamajek confirmed the brown dwarf status of WISE 0414 using observations taken using the 200-inch Hale Telescope at Palomar Observatory outside San Diego.

About Backyard Worlds: Planet 9

The ongoing Backyard Worlds: Planet 9 project lets anyone join the quest to find more mysterious objects in spacecraft data. Citizen scientists using this project have discovered a wealth of astronomical treasures, including more than 1,600 brown dwarfs and the oldest, coldest white dwarf surrounded by a disk of debris.

About 150,000 people have participated so far. Check it out at http://backyardworlds.org/

About WISE and NEOWISE

The WISE spacecraft was placed in hibernation in February 2011 after completing its primary astrophysics mission, but in late 2013, the spacecraft was reactivated, renamed NEOWISE, and assigned a second mission dedicated to identifying and characterizing the population of near-Earth objects while also providing information about the size and composition of more distant asteroids and comets.

JPL manages and operates the NEOWISE mission for NASA's Planetary Defense Coordination Office within the Science Mission Directorate in Washington. The principal investigator, Amy Mainzer, is at the University of Arizona in Tucson. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science data processing takes place at IPAC at Caltech in Pasadena. Caltech manages JPL for NASA.

JPL managed and operated WISE for NASA's Science Mission Directorate. Edward Wright at the University of California, Los Angeles was the principal investigator. The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Maryland.

Related link:

The Astrophysical Journal: https://arxiv.org/abs/2007.03836

For more information about NEOWISE, visit: 

https://www.nasa.gov/neowise

http://neowise.ipac.caltech.edu/

For more information about WISE, visit:

http://www.nasa.gov/wise

https://www.jpl.nasa.gov/wise/

Images (mentioned), Text, Credits: NASA/Elizabeth Landau/JPL/Calla Cofield.

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