Connect with us

Science

Astronomers Discover Hundreds of High-Velocity Stars, Many on Their Way Out of the Milky Way – Universe Today

Published

 on


Within our galaxy, there are thousands of stars that orbit the center of the Milky Way at high velocities. On occasion, some of them pick up so much speed that they break free of our galaxy and become intergalactic objects. Because of the extreme dynamical and astrophysical processes involved, astronomers are most interested in studying these stars – especially those that are able to achieve escape velocity and leave our galaxy.

However, an international team of astronomers led from the National Astronomical Observatories of China (NAOC) recently announced the discovery of 591 high-velocity stars. Based on data provided by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the ESA’s Gaia Observatory, they indicated that 43 of these stars are fast enough to escape the Milky Way someday.

The study was published in The Astrophysical Journal Supplement Series on Dec. 17th. The study was led by Dr. LI Yinbi, an NAOC astronomer, and included researchers from the Chinese Academy of Sciences (CAS), the Max-Planck Institute for Astronomy (MPIA), the Institute for Advanced Study, the European Southern Observatory (ESO), the ExtantFuture Technology Co., the Institute of Statistical Mathematics in Tokyo, and multiple universities.

An artist’s conception of a hypervelocity star that has escaped the Milky Way. Credit: NASA

In terms of astrophysical studies, high-velocity stars are a relatively recent discovery. The first was observed in 2005, and in the subsequent 15 years, over 550 have been discovered by multiple observatories. From these, astronomers have been able to deduce four subclasses of high-velocity stars, which include: hypervelocity stars, runaway stars, hyper-runaway stars, and fast halo stars.

This latest discovery is especially significant then because it effectively doubles the number of known high-velocity stars, which are quite rare in our galaxy. “The 591 high-velocity stars discovered this time doubled the total number previously discovered, bringing the current total number exceeding 1,000,” said Dr. Li.

Hypervelocity stars (HVS), the fastest of the bunch, are especially interesting because they have achieved relativistic speeds (a fraction of the speed of light). In fact, astronomers have estimated that with the right kind of gravitational acceleration, hypervelocity stars can reach 1/10th to 1/3rd the speed of light – roughly 30,000 to 100,000 km/s (18,640 to 62,130 mi/s).

It is these stars that have the escape velocity needed to leave the Milky Way. Said Prof. LU Youjun from NAOC, a co-author of this paper:

“Though rare in the Milky Way, high-velocity stars, with unique kinematics, can provide deep insight into a wide range of Galactic science, from the central supermassive black hole to distant Galactic halo.”

The positions and reconstructed orbits of 20 high-velocity stars, represented on top of an artistic view of the Milky Way. Credit: ESA/Marchetti et al. 2018/NASA/ESA/Hubble

“Rare” is certainly an apt description. According to previous estimates made by astrophysicists, there are likely to be just 1000 HVS in our galaxy (that’s 0.0000005 % of the galactic population). But given their speed and the vast distances they travel, tracking these stars and creating a database of their movements could tell us a great deal about a number of cosmic mysteries.

For the sake of their study, the international team relied in part on data provided by LAMOST. In addition to being the largest optical telescope in China, LAMOST has the highest spectral acquisition rate of any telescope in the world and can observe about 4,000 celestial objects in a single exposure. Since it began conducting surveys in 2012, it has established the world’s largest spectra database.

In addition, the team relied on astrometric measurements performed by the Gaia Observatory, which was launched by the European Space Agency (ESA) in 2013. Since then, it has gathered information on the location, proper motion, and velocity of over 1.3 billion celestial objects, making it the largest astrometric database in the world. Both observatories and their massive databases have been invaluable in the detection and study of HVS.

Based on the motion and composition of the objects they observed, the research team identified 591 HVS that originated in the Milky Way’s inner halo. “Their low metallicities indicate that the bulk of the stellar halo formed as a consequence of the accretion and tidal disruption of dwarf galaxies,” said co-author Prof. Zhao Gang of the CAS School of Astronomy and Space Science.

One of the greatest takeaways from this study the way it demonstrates how combining multiple large surveys can lead to the discovery of rare objects. In the future, astronomers will be able to draw from even larger databases containing survey data provided by next-generation instruments. This data will be especially useful in the study of Dark Matter, the mysterious mass that constitutes 27% of the mass-energy density of the Universe.

By tracking the movement of HVS, astrophysicists will be able to better constrain the shape of the Milky Way’s dark matter halo. In addition, they could tell us a great deal about the formation and evolution of the Milky Way itself, as HVS are believed to be the result of galactic mergers and other extreme gravitational forces (i.e. supermassive holes). Having more to study could therefore help astronomers create a history of past galactic mergers.

It has also been ventured that HVS could allow astrophysicists to accurately constrain the mass of our galaxy, something that remains unresolved. On top of all that, previous research has indicated that HVS can carry their planetary systems with them, which could be one of the ways that life is spread throughout the cosmos (intergalactic panspermia).

Further Reading: Chinese Academy of Sciences, The Astrophysical Journal

Let’s block ads! (Why?)



Source link

Continue Reading

Science

First Private Crew Will Visit Space Station. The Price Tag: $55 Million Each – KCCU

Published

 on


A crew of private astronauts will pay around $55 million each to spend about eight days at the International Space Station next January in what would be a new step for joint private-public space missions. Axiom Space, a Houston company, says the trip will be led by former NASA astronaut and space station commander Michael López-Alegría.

The proposed Ax-1 mission will use a SpaceX rocket to put three paying customers — American Larry Connor, Canadian Mark Pathy and Israeli Eytan Stibbe – into low-Earth orbit on the space station. All of the trio are wealthy entrepreneurs and investors. The group will be under the command of López-Alegría, who is now an executive at Axiom.

It would be the first time an entirely private mission sends astronauts to the International Space Station. Russia sold the first ride to the station to a private citizen, American businessman Dennis Tito, in 2001.

All of the private astronauts for the upcoming mission are far older than the average NASA astronaut’s age of 34. The space agency does not have age restrictions for astronaut candidates, who generally range from 26 to 46 years old. At 70, Connor is surpassed in age only by John Glenn, who flew on the space shuttle when he was 77.

Under NASA’s rules for private astronaut missions, Axiom must ensure its astronauts meet the space agency’s medical standards. They must also undergo training and certification procedures required for crew members of the International Space Station.

While the paying customers represent a new era of space tourism, they will also perform research as the space station whizzes over the Earth.

Connor will work with the Mayo Clinic and Cleveland Clinic on research projects, Axiom says, while Pathy will collaborate with the Canadian Space Agency and the Montreal Children’s Hospital. Stibbe plans to do experiments for Israeli researchers, working with the Ramon Foundation and Israel’s space agency.

“We sought to put together a crew for this historic mission that had demonstrated a lifelong commitment to improving the lives of the people on Earth, and I’m glad to say we’ve done that with this group,” Axiom Space President and CEO Michael Suffredini said as the company announced the crew.

Similar missions are planned for the future, Suffredini said. Axiom hopes to arrange up to two trips per year — and the company also wants to build its own privately funded space station. Under that plan, its modules would be attached to the space station as soon as 2024. And when the space station is retired, the Axiom modules would break off to continue in orbit on their own.

NASA announced its plans to open the International Space Station to commercial activities in June 2019, saying it wants businesses to use innovation and ingenuity to speed up development of “a thriving commercial economy in low-Earth orbit.”

The space agency has a plan to recoup the steep costs of a private citizen visiting the space station. Its pricing policy lists expenses such as a daily fee of $11,250 per person for “regenerative life support and toilet” and $22,500 per person for crew supplies such as food and air. The price sheet also includes a data plan, priced at $50 per gigabyte.

Copyright 2021 NPR. To see more, visit https://www.npr.org.

Let’s block ads! (Why?)



Source link

Continue Reading

Science

New app makes figuring out CBRM solid waste collection schedule easier – CBC.ca

Published

 on



Residents of Cape Breton Regional Municipality will now have an easy way to find out what day their solid waste collection falls on.

A new app has been developed that allows residents to enter their address and find the specific day and time their garbage or recycling should be sitting at the end of their driveway.

The CBRM solid waste department had been working for months with an app developer who has made similar apps throughout North America.

Francis Campbell, the solid waste manager for CBRM, said one of the best parts of the app is the database that allows residents to search for what to do with specific waste materials.

“The search tool will educate residents in how to recycle or properly dispose of materials, and it’ll provide the curbside drop-off locations,” said Campbell.

The app sets up reminders through the calendar on a person’s phone so they will be reminded the night before to put out their garbage, recycling or green bin.

It also will be able to quickly let residents know if there is a cancellation or delay on a collection day, as well as post holiday cancellations.

CBRM deputy mayor Earlene MacMullin downloaded the app and said it was ‘fantastic.’ (CBRM)

Earlene MacMullin, the deputy mayor of CBRM, said she downloaded the app while getting the presentation on it and already found it useful.

“This is already fantastic and it seems very simplistic. I know deep down it isn’t, but in my first three minutes of using it, I encourage residents to check this out,” said MacMullin.

There will also be a web-based version along with online information regarding waste collection on the CBRM website. This will be coming when the app is fully launched in a few weeks time.

Coun. Cyril MacDonald said he is glad that people who do not have access to a smartphone can still have access to the information. 

“We’re not removing a service. You’re still able to get your calendar printed off, so I think this is great,” said MacDonald.

People who may not have access to a computer or a smartphone will still have the option to call the CBRM solid waste hotline to find out the information they need.

Mayor Amanda McDougall said she is happy she has an easy way to never forget what waste is being collected each week.

The app is now available for download through smartphone app stores.

MORE TOP STORIES

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Limited COVID-19 data until Friday as Middlesex-London Health Unit moves to new database – Globalnews.ca

Published

 on


The Middlesex-London Health Unit (MLHU) says it will only be able to provide limited COVID-19 information for the region over the next few days as it implements a new database for its website.

After using an internal case and contact management tool to collect local COVID-19 data, MLHU will now switch to Salesforce, a database system that’s already being used by the Ontario government.

Migrating to the new database means the health unit will be able to provide only limited information about case numbers, recoveries and deaths during daily updates for Wednesday and Thursday on MLHU’s COVID-19 dashboard.

[ Sign up for our Health IQ newsletter for the latest coronavirus updates ]

Regular updating of the dashboard is set to resume on Friday, but MLHU notes some data fields may be missing in subsequent updates as staff adjust to the new database.

Story continues below advertisement

The health unit adds that it intends to have any potential missing information filled in once the new database is fully implemented.

Along with aligning the regional health unit with the province’s database, Salesforce will also allow the health unit to provide virtual notifications to those diagnosed with COVID-19.

The notifications will be sent via text message and will notify recipients of their test results, provide them information about self-isolating and prompt them to provide information about their symptoms and close contacts.

© 2021 Global News, a division of Corus Entertainment Inc.

Let’s block ads! (Why?)



Source link

Continue Reading

Trending