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The Milky Way Broke one of its Arms – Universe Today



The Milky Way galaxy is our home, and yet in some ways, it is the least understood galaxy. One of the biggest challenges astronomers have is in understanding its large-scale structure. Because we’re in the midst of it all, mapping our galaxy is a bit like trying to map the size and shape of a wooded park while standing in the middle of it.

One of the ways astronomers can map our galaxy is to measure the position and distance of thousands upon thousands of stars. This is one of the main goals of the Gaia mission, which studies the location and motion of more than a billion stars. Gaia has already revealed details in the structure of the Milky Way, such as a wave pattern among some stars.

The Eagle, Omega, Triffid, and Lagoon Nebulae, imaged by NASA’s infrared Spitzer Space Telescope. Credit: NASA/JPL-Caltech

Another method is to look at specific objects in our galaxy, such as star-forming nebulae. Star-forming nebulae tend to be located within the spiral arms of a galaxy, where there is the most gas and dust. The Spitzer infrared space telescope has measured the distances to young stars within many nebulae, which helped us confirm that the Milky Way has four main spiral arms.

A new study combines data from Gaia and Spitzer, comparing the location of some nebulae with the overall spiral distribution of stars.[^1] The study focused on a main spiral arm within the galaxy known as the Sagittarius Arm. It is the spiral arm just inward from the Sun’s arm of Orion. The team hoped to measure an aspect of the spiral arm known as the pitch angle. It tells you how tightly wound a spiral arm is. The larger the pitch angle, the more open the spiral arms are. In the case of the Sagittarius Arm, the pitch angle is about 12 degrees. But pitch the angle of some nebulae are very different.

Astronomers found a break in our galaxy’s Sagittarius Arm. Credit: NASA/JPL-Caltech

The team looked at four prominent nebulae in our night sky: the Eagle Nebula (which contains the Pillars of Creation), the Omega Nebula, the Trifid Nebula, and the Lagoon Nebula. These four nebulae are in the same general region and were used in the 1950s to confirm the existence of the Sagittarius Arm. This new study pinned down the location of these nebulae and other stars and found the region has a pitch angle of 60 degrees.

This doesn’t mean our original measure of the Sagittarius Arm is wrong, but it does point to a type of structure known as galactic spurs. Some spiral galaxies have very smooth spiral arms, where gas, dust, and star-forming regions are all along the same curve. Other spiral galaxies have more broken spiral arms, with small feathery offshoots called spurs. We don’t know for sure which type of galaxy the Milky Way is, but this new study points to it being the latter.

Reference: Kuhn, M. A., et al. “A high pitch angle structure in the Sagittarius Arm.” Astronomy & Astrophysics 651 (2021): L10.

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A Mystery Rocket Left A Crater On The Moon – Forbes



While we think of the moon as a static place, sometimes an event happens that reminds us that things can change quickly.

On March 4, a human-made object (a rocket stage) slammed into the moon and left behind a double crater, as seen by NASA’s Lunar Reconnaissance Orbiter (LRO) mission.

Officials announced June 23 that they spotted a double crater associated with the event. But what’s really interesting is there’s no consensus about what kind of rocket caused it.

China has denied claims that the rocket was part of a Long March 3 rocket that launched the country’s Chang’e-5 T1 mission in October 2014, although the orbit appeared to match. Previous speculation suggested it might be from a SpaceX rocket launching the DISCOVR mission, but newer analysis has mostly discredited that.

On a broader scale, the value of LRO observations like this is showing how the moon can change even over a small span of time. The spacecraft has been in orbit there since 2009 and has spotted numerous new craters since its arrival.

It’s also a great spacecraft scout, having hunted down the Apollo landing sites from orbit and also having tracked down a few craters from other missions that slammed into the moon since the dawn of space exploration.

It may be that humans return to the moon for a closer-up look in the coming decade, as NASA is developing an Artemis program to send people to the surface no earlier than 2025.

LRO will also be a valuable scout for that set of missions, as the spacecraft’s maps will be used to develop plans for lunar bases or to help scout safe landing sites for astronauts.

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A new planet hunter awakens: NIRPS instrument sees first light – News | Institute for Research on Exoplanets



The Near InfraRed Planet Searcher (NIRPS) instrument, developed in part at the Université de Montréal and the Université Laval, has successfully performed its first observations. Mounted on ESO’s 3.6-m telescope at the La Silla Observatory in Chile, NIRPS’s mission is to search for new exoplanets around stars in the solar neighbourhood.

This photograph shows the NIRPS instrument and its adaptive optics system, which is installed at ESO’s 3.6-metre telescope. The light collected from the telescope is aimed through a series of mirrors before being injected into an optical fibre. Thanks to this adaptive-optics system, disturbances in the Earth’s atmosphere can be corrected for, allowing for sharper observations. Credit: N. Blind (Observatoire de Genève)/NIRPS consortium/ESO.

“NIRPS has been a long time in the making, and I’m thrilled with how this mission has come together!” says René Doyon, Director of the Observatoire du Mont-Mégantic and Institute for Research on Exoplanets, Université de Montréal, and co-Principal Investigator of NIRPS. “This incredible infrared instrument will help us find the closest habitable worlds to our own Solar System.”

The instrument will focus its search on rocky worlds, which are key targets for understanding how planets form and evolve, and are the most likely planets where life may develop. NIRPS will search for these rocky exoplanets around small, cool red dwarf stars — the most common type of stars in our Milky Way galaxy, which have masses from about two to ten times smaller than our Sun.

NIRPS will search for exoplanets using the radial velocity method. As a planet orbits a star, its gravitational attraction causes the star to “wobble” slightly, causing its light to be redshifted or blueshifted as it moves away from or towards Earth. By measuring the subtle changes in the light from the star, NIRPS will help astronomers measure the mass of the planet as well as other properties.

NIRPS will search for these spectral wobbles using near-infrared light as this is the main range of wavelengths emitted by such small, cool stars. It joins the High Accuracy Radial velocity Planet Searcher (HARPS) in the hunt for new rocky worlds. HARPS, which has been installed on ESO’s 3.6-m telescope at the La Silla Observatory in Chile since 2003, also uses the radial velocity method, but operates using visible light. Using both instruments simultaneously will provide a more comprehensive analysis of these rocky worlds.

Another key difference between the two instruments is that NIRPS will rely on a powerful adaptive optics system. Adaptive optics is a technique that corrects for the effects of atmospheric turbulence, which cause stars to twinkle. By using it, NIRPS will more than double its efficiency in both finding and studying exoplanets.

“NIRPS joins a very small number of high-performance near-infrared spectrographs and is expected to be a key player for observations in synergy with space missions like the James Webb Space Telescope and ground-based observatories,” adds François Bouchy, from the University of Geneva, Switzerland, and co-Principal Investigator of NIRPS.

Discoveries made with NIRPS and HARPS will be followed up by some of the most powerful observatories in the world, such as ESO’s Very Large Telescope and the upcoming Extremely Large Telescope in Chile (for which similar instruments are in development). By working together with both space- and ground-based observatories, NIRPS will be able to gather clues on an exoplanet’s composition and even look for signs of life in its atmosphere.

To be able to operate in the infrared, the Near Infrared Planet Searcher (NIRPS) instrument needs to be kept extremely cool, to prevent heat from interfering with the observations. Here we see the cylindrical cryogenic chamber within which the instrument’s optical parts are installed. The cryogenic chamber keeps the components in a vacuum environment and cooled down to a freezing -190 degrees Celsius. Credit: F. Bouchy (Observatoire de Genève)/NIRPS consortium/ESO.

NIRPS was built by an international collaboration led by the Observatoire du Mont-Mégantic and the Institute for Research on Exoplanets team at the Université de Montréal in Canada and the Observatoire Astronomique de l’Université de Genève in Switzerland. Much of the mechanical and optical assembly and testing of the instrument was performed over the last few years at Université Laval’s Centre for Optics, Photonics and Lasers (COPL) laboratories by Prof. Simon Thibault and his team. The National Research Council of Canada’s Herzberg Astronomy and Astrophysics Research Centre contributed to the conception and construction of the spectrograph.

“After two years of integrating and testing the instrument in the lab, it is amazing for the optical engineering team to see NIRPS on the sky.” mentions Prof. Simon Thibault who is affiliated with the COPL and iREx and who overviewed optical integration and test phases at Université Laval.

Here we see the first raw data from the NIRPS instrument, the spectrum of Barnard’s star. Each horizontal line corresponds to a narrow region of light where both the absorption lines from the star and the absorption from the Earth’s atmosphere are visible. The dotted lines correspond to the so-called comb spectrum, a “ruler” that is used as a reference for the horizontal lines, so scientists can know which wavelengths of light they correspond to. Credit: ESO/NIRPS consortium.

Many Canadian members of the NIRPS have been working on site at La Silla for the instrument’s commissioning period and will continue to do so over the next several months to ensure the NIRPS’s scientific operations. The NIRPS science team, which includes several Canadian astronomers, is guaranteed 720 nights on the instrument during its first 5 years of operations due to their important contribution to the project. While the whole team was excited for NIRPS’s first light, it is safe to say that the best is yet to come!

More Information

The institutes involved in the NIRPS consortium are the Université de Montréal, Canada; the Université de Genève, Observatoire Astronomique, Switzerland; the Instituto de Astrofísica e Ciências do Espaço, Porto, Portugal; the Instituto de Astrofísica de Canarias, Spain; the Université de Grenoble, France; and the Universidade Federal do Rio Grande do Norte, Brazil.

The Canadian NIRPS team, led by Université de Montréal/The Institute for Research on Exoplanets/Observatoire du Mont-Mégantic and including Université Laval, the National Research Council of Canada’s Herzberg Astronomy and Astrophysics Research Centre, and the Royal Military College, was awarded funding by the Canadian Fund for Innovation to build the NIRPS instrument.


René Doyon
Professor, NIRPS co-Principal Investigator
Institute for Research on Exoplanets and Observatoire du Mont-Mégantic — Université de Montréal
Tel: +1 514 343 6111 x3204

Frédérique Baron
NIRPS Deputy Project Manager
Observatoire du Mont-Mégantic — Université de Montréal
Tel: +1 514 277 2858

Simon Thibault
Professor, NIRPS optical engineering team
Centre for Optics, Photonics and Lasers — Université Laval
Tel: +1 418 656 2131 x 412766

Anne-Sophie Poulin-Girard
Research Associate, NIRPS optical engineering team
Centre for Optics, Photonics and Lasers — Université Laval
Tel: +1 418 656 2131 x 404646

Nathalie Ouellette
Institute for Research on Exoplanets — Université de Montréal
Tel: +1 613 531 1762


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Rocket Lab’s CAPSTONE mission to the moon is key to establishing a lunar space station – TechCrunch



It may look like Rocket Lab is just launching a microwave-sized hunk of metal to the moon — but it’s crucial for our future in space

“Going to the moon is no joke.” So said Rocket Lab CEO Peter Beck, just days before the planned launch of CAPSTONE, a watershed mission for both NASA and the private space industry.

The mission is important, though you might not assume so based on the stats of the CAPSTONE CubeSat on its own: It’s about the size of a microwave oven and weighs in at just 55 pounds. But the end goal of the spacecraft’s roughly six-month stint in lunar orbit is to chart a favorable trajectory for a crewed station that will orbit the moon. Once established, that platform, dubbed Gateway, could unlock a whole new chapter in human space exploration.

Consider CAPSTONE (which stands for Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment) the first in-space step in NASA’s Artemis program, an ambitious plan to return humans to the moon by the middle of this decade. The Gateway platform could be used as a way station for lunar landers, a resupply junction for astronauts exploring the moon — or even a transfer point for missions to Mars and beyond.

Image Credits: NASA

The mission isn’t just a big deal for the Artemis program and public space exploration: Notably, it’s the result of a patchwork of collaboration between private industry and the space agency. The list of partners on NASA’s website for the mission includes:

And, of course, Rocket Lab for the launch services.

CAPSTONE is launching aboard a Rocket Lab Electron rocket from the company’s site on New Zealand’s remote Māhia Peninsula. “This is the highest mass and the highest performance Electron has ever had to fly by quite some margin,” Beck said. “The vehicle is absolutely stretched to its limits with respect to performance.”

In addition to actually launching the mission, Rocket Lab developed a special variant of its Photon spacecraft for this endeavor, which it’s calling the Lunar Photon. That spacecraft will conduct a series of orbits over a period of around six to eight days, increasing the velocity and apogee of the orbit over time. Then, Photon will perform the final burn, called the trans-lunar injection, which will set it on its course to the moon. Around 20 minutes after the injection, Photon and CAPSTONE will separate and the CubeSat alone will conduct the remaining maneuvers to reach its target orbit around the moon.

“The moon is a long way away,” Beck said, referring to the complexities of Photon’s maneuvers. “You’re traveling at huge velocities. So it only takes a smallest fraction of an angle error or a velocity error, and you just shoot way past where you need to be.”

“It’s like firing a bullet millions of kilometers, and it’s got to be exactly in the right place.”

An unusual orbit

The exact orbit that CAPSTONE will be exploring is called a near-rectilinear halo orbit (NRHO). That orbit, in the shape of a necklace, will bring CAPSTONE as close as 1,000 miles to the moon’s surface and as far away as 40,000 miles. Although the shape is odd, it’s a very stable orbit, which means greater efficiency and less use of propellant. NRHO was up against competing orbits, including low lunar orbit and distant retrograde orbit, as the ideal trajectory for Gateway; but as NASA explains, NRHO is a “best of both worlds” option that’ll provide astronauts with easy access to the lunar surface, a continuous line of sight to (and communication with) Earth and access to deep space.

But testing the NRHO orbit is not the only point of the mission. The CubeSat will also help NASA understand navigation, or how to generate an accurate estimation of Gateway’s trajectory, and station-keeping.

“Because the NRHO is marginally stable, Gateway and CAPSTONE will both require a gentle ‘nudge’ about once a week to stay in orbit,” Ethan Kayser, CAPSTONE mission design lead at Advanced Space, explained in a Reddit post. “CAPSTONE will be using the same strategy to design and execute these stationkeeping maneuvers, which occur once each revolution.” The eight propulsion thrusters built by Stella Exploration will be key to conducting these maneuvers.

CAPSTONE will arrive at its lunar orbit on November 13. After a roughly six-month orbital mission, NASA plans to crash the spacecraft into the moon at the end of its life. The launch is set to take place during an instantaneous launch window at 5:55 AM EDT on Tuesday, June 28, so be sure to follow TechCrunch for live coverage and reporting on the outocome of the mission launch.

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