TESS resumes normal operations
Engineers have apparently cleared the issue that caused TESS’s computers to reset unexpectedly, thus putting the spacecraft into safe mode, and have now resumed normal operations.
Tag: astronomy
Two solar eclipses coming to the U.S. next year
Map by Michael Zeiler (GreatAmericanEclipse.com). Click for original.
The U.S. public will get to see two different solar eclipses during a six month period, starting one year from today.
The map to the right, cropped and reduced to post here, shows the dates and the path of both eclipses.
On 14 October 2023, anyone under clear skies within a path that sweeps from Oregon to Texas and then through parts of Central and South America will see an annular (“ring”) eclipse. Just six months later, on 8 April 2024, a total solar eclipse will sweep from Mexico to Texas to the Canadian Maritimes, plunging day into night and revealing the magnificent solar corona for anyone fortunate to be within the path of totality and under clear skies. Nearly everyone in North America will have a partial solar eclipse both days.
As always with eclipses, great care must be taken to watch it. With the 2017 eclipse Diane and I had good filters, but even so I noticed my eyes were very tired for several days afterward.
Final decision: Arecibo will not be rebuilt
The National Science Foundation has made it official: It will not rebuild the Arecibo Observatory in Puerto Rico, though it will fund the facility as an education center instead.
Now, the National Science Foundation (NSF), which owns the site, has determined that despite scientists’ pleas, Arecibo Observatory won’t be getting any new telescope to replace the loss. The new education project also doesn’t include any long-term funding for the instruments that remain operational at the observatory, including a 40-foot (12 m) radio dish and a lidar system.
…Instead, the NSF intends to build on the observatory’s legacy as a key educational institution in Puerto Rico by transforming the site into a hub for science, technology, engineering and math (STEM) education, due to open in 2023, according to a statement. The observatory is also home to the Ángel Ramos Foundation Science and Visitor Center, which opened in 1997.
It seems unclear how this education center will function. Will it be a school that students attend? Or simply a type of museum with a visitors center? This new plan appears to call for about $2 million per year in funding, which does not appear enough to do much of anything, other than to keep the lights on and hang some pretty astronomy pictures on the walls.
The known near Earth asteroid catalog now tops 30,000
The catalog of known near Earth asteroids that have been identified using a number of survey telescopes in space and on the Earth now totals 30,039. As defined at the link:
An asteroid is called a near-Earth asteroid (NEA) when its trajectory brings it within 1.3 Astronomical Units (au) of the Sun. 1 au is the distance between the Sun and Earth, and so NEAs can come within at least 0.3 au, 45 million km, of our planet’s orbit.
Currently, near-Earth asteroids make up about a third of the roughly one million asteroids discovered so far in the Solar System. Most of them reside in the asteroid belt between Jupiter and Mars.
NEAs are also called NEOs (Near Earth Objects). The chart above, produced by the Center for NEO Studies which tracks these objects, shows the number of NEAs discovered over time.
Of the 30,039 now known, about 1,400 have orbits with “a non-zero” chance of hitting the Earth. None however will do so in the next hundred years at least.
Though the pace of discovery is vastly improving — as indicated by the steep rise in the curve in the graph — only when that curve begins to flatten out will we know that we are getting close to having a more-or-less complete survey of these objects.
Shells of dust surrounding massive binary star
Click for full image.
Cool image time! Using the Webb telescope, astronomers have detected a series of concentric shells surrounding the massive binary star dubbed Wolf-Rayet 140.
The infrared image to the right shows these shells quite clearly. As noted by astronomer Ryan Lau:
“On the night that my team’s Early Release Science observations of the dust-forming massive binary star Wolf-Rayet (WR) 140 were taken, I was puzzled by what I saw in the preview images from the Mid-Infrared Instrument (MIRI). There seemed to be a strange-looking diffraction pattern, and I worried that it was a visual effect created by the stars’ extreme brightness. However, as soon as I downloaded the final data I realized that I was not looking at a diffraction pattern, but instead rings of dust surrounding WR 140 – at least 17 of them.
“I was amazed. Although they resemble rings in the image, the true 3D geometry of those semi-circular features is better described as a shell. The shells of dust are formed each time the stars reach a point in their orbit where they are closest to each other and their stellar winds interact. The even spacing between the shells indicates that dust formation events are occurring like clockwork, once in each eight-year orbit. In this case, the 17 shells can be counted like tree rings, showing more than 130 years of dust formation. Our confidence in this interpretation of the image was strengthened by comparing our findings to the geometric dust models by Yinuo Han, a doctoral student at the University of Cambridge, which showed a near-perfect match to our observations.
Furthermore, the spectroscopy from Webb says these dust shells are carbon-enriched, showing that the dust released by these aged massive stars is a significant source of the carbon in the universe, the fundamental atom needed for life.
DART’s impact shortened Dimorphus’s orbit around Didymos by 32 minutes
LICIACube Explorer image just after the DART
impact. Dimorphus is the blob near the top.
After two weeks of analyzing the orbit of Dimorphus around its parent asteroid Didymos, astronomers have determined that the impact of DART on Dimorphus shortened its orbit by 32 minutes.
Prior to DART’s impact, it took Dimorphos 11 hours and 55 minutes to orbit its larger parent asteroid, Didymos. Since DART’s intentional collision with Dimorphos on Sept. 26, astronomers have been using telescopes on Earth to measure how much that time has changed. Now, the investigation team has confirmed the spacecraft’s impact altered Dimorphos’ orbit around Didymos by 32 minutes, shortening the 11 hour and 55-minute orbit to 11 hours and 23 minutes. This measurement has a margin of uncertainty of approximately plus or minus 2 minutes.
Before its encounter, NASA had defined a minimum successful orbit period change of Dimorphos as change of 73 seconds or more. This early data show DART surpassed this minimum benchmark by more than 25 times.
It also appears the ejecta from the impact — much greater than expected — helped propel Dimorphus, a result that I think was also not expected.
Researchers are now shifting to studying the debris and asteroid itself, to better understand what happened as well as the nature of Dimorphus itself. This will also include a European probe dubbed Hera that will launch in 2024 an dvisit both asteroids in 2026.
Webb gets first direct infrared image of exoplanet
Using the Webb Space Telescope, scientists have obtained that telescope’s first direct infrared image of an exoplanet, covering four different wavelengths.
The image to the right is from the wavelength image with the least distortion (formed by Webb’s own optics and the shape of its mirror and indicated by the faint ring surrounding the planet). The star indicates the masked location of the star itself.
The planet is about seven times the mass of Jupiter and lies more than 100 times farther from its star than Earth sits from the sun, direct observations of exoplanet HIP 65426 b show. It’s also young, about 10 million or 20 million years old, compared with the more than 4-billion-year-old Earth.
You can download the full research paper here.
Chandra takes an X-ray look at early Webb infrared observations
Chandra’s X-ray view of the Cartwheel Galaxy
Webb’s infrared view of the Cartwheel Galaxy
Click for full image.
Hubble’s optical view of the Cartwheel Galaxy. Click for original image.
Astronomers have now taken X-ray images using the orbital Chandra X-ray Observatory of four of the first Webb Space Telescope observations. The four targets were the Cartwheel Galaxy, Stephan’s Quintet, galaxy cluster SMACS 0723.3–7327, and the Carina Nebula.
The three images to the right illustrate the importance of studying astronomy across the entire electromagnetic spectrum. Each shows the Cartwheel Galaxy as seen by three of the world’s most important space-based telescopes, each looking at the galaxy in a different wavelength.
The top picture is Chandra’s new X-ray observations. As the press release notes,
Chandra data generally show higher-energy phenomena (like superheated gas and the remnants of exploded stars) than Webb’s infrared view. … X-rays seen by Chandra (blue and purple) come from superheated gas, individual exploded stars, and neutron stars and black holes pulling material from companion stars.
The middle picture was produced by Webb, shortly after the start of its science operations. It looks at the galaxy in the infrared.
In this near- and mid-infrared composite image, MIRI data are colored red while NIRCam data are colored blue, orange, and yellow. Amidst the red swirls of dust, there are many individual blue dots, which represent individual stars or pockets of star formation. NIRCam also defines the difference between the older star populations and dense dust in the core and the younger star populations outside of it.
The bottom picture was taken by the Hubble Space Telescope in 1995. I have rotated the image to match the others. It looks at the galaxy in optical wavelengths, the wavelengths that our eyes perceive.
Note how bright the central galactic region is in the infrared and optical, but is invisible in X-rays. Chandra is telling us that all the most active regions in the Cartwheel are located in that outer ring, not in its center.
Two days after DART’s impact of Dimorphus, ejected dust extends like a comet tail out more than 6,000 miles
Click for full image.
Using a telescope in Chile, astronomers photographed the ejecta two days after the impact of DART into the 525-foot-wide asteroid Dimorphus, and detected a tail of dust extending out more than 6,000 miles.
The picture to the right, cropped and reduced to post here, shows that tail.
In this new image, the dust trail — the ejecta that has been pushed away by the Sun’s radiation pressure, not unlike the tail of a comet — can be seen stretching from the center to the right-hand edge of the field of view. … At Didymos’s distance from Earth at the time of the observation, that would equate to at least 10,000 kilometers (6000 miles) from the point of impact.
Didymos is the larger parent asteroid that Dimorphus orbits.
It is still too soon to get the numbers on how Dimorphus’s path in space was changed by that impact. In fact, we still really don’t have a clear idea what is left of Dimophus itself. The ejecta cloud needs to clear somewhat to see what’s hidden inside it.
Interacting galaxies
Click for full image.
The news is light this morning, so this cool image will be the first of three. The picture to the right, cropped and reduced to post here, was taken by the Hubble Space Telescope and released today. From the caption:
The two interacting galaxies making up the pair known as Arp-Madore 608-333 seem to float side by side in this image from the NASA/ESA Hubble Space Telescope. Though they appear serene and unperturbed, the two are subtly warping one another through a mutual gravitational interaction that is disrupting and distorting both galaxies.
I did a search for any research of this galaxy pair, and found that its identification was only part of a larger survey, with only a little research done on its spectroscopy. Thus, I can’t tell you the size or distance, or how far apart from each other these galaxies lie.
SpaceX and Jared Isaacman offer private mission to NASA to raise Hubble’s orbit
Capitalism in space: In a press release issued yesterday, NASA revealed that it has signed an unfunded agreement with SpaceX and Jared Isaacman’s Polaris program (which has purchased a series of manned missions on Dragon) to study the possibility of sending one of those private manned missions to the Hubble Space Telescope to raise its orbit.
SpaceX – in partnership with the Polaris Program – proposed this study to better understand the technical challenges associated with servicing missions. This study is non-exclusive, and other companies may propose similar studies with different rockets or spacecraft as their model.
Teams expect the study to take up to six months, collecting technical data from both Hubble and the SpaceX Dragon spacecraft. This data will help determine whether it would be possible to safely rendezvous, dock, and move the telescope into a more stable orbit.
In my book describing the history of the people who created Hubble, The Universe in a Mirror, I repeatedly noted how throughout its history people have tried to kill it, first in the design phase, then in the budget, then during construction, then after it was launched and the mirror was found to be ground incorrectly, and then after the Columbia accident when NASA management tried to cancel its last shuttle servicing mission.
Every attempt failed. As I have noted in that book and many times since its publication, Hubble is a telescope that will not die. NASA has for years intended to launch a mission to de-orbit it when its orbit had decayed enough that it was unstable. I’ve always said that when that time came, someone would propose and push for a mission to instead raise that orbit.
That prediction is now coming true. Though no robot arm exists yet for Dragon to use to grab Hubble in any rendezvous attempt, creating one is hardly difficult. At that point raising the telescope’s orbit becomes relatively trivial.
Whether such a mission could do more, such as replace Hubble’s ailing gyroscopes, is unknown. It would be foolish however not to review that possibility as well.
Initial Webb results revised because telescope wasn’t yet fully calibrated
The uncertainty of science: Though it appears that no results will have to be abandoned, the scientists who published some of the very first results from the Webb Space Telescope have been scrambling to adjust and revise their papers because the telescope is only now getting fully calibrated.
“This caused a little bit of panic,” says Nathan Adams, an astronomer at the University of Manchester, UK, who, along with his colleagues, pointed out the problem in a 9 August update to a preprint they had posted in late July3. “For those including myself who had written a paper within the first two weeks, it was a bit of — ‘Oh no, is everything that we’ve done wrong, does it all need to go in the bin?’”
To try to standardize all the measurements, the STScI is working through a detailed plan to point Webb at several types of well-understood star, and observe them with every detector in every mode for every instrument on the telescope4. “It just takes a while,” says Karl Gordon, an astronomer at the STScI who helps lead the effort.
In the meantime, astronomers have been reworking manuscripts that describe distant galaxies on the basis of Webb data. “Everyone’s gone back over and had a second look, and it’s not as bad as we thought,” Adams says. Many of the most exciting distant-galaxy candidates still seem to be at or near the distance originally estimated. But other preliminary studies, such as those that draw conclusions about the early Universe by comparing large numbers of faint galaxies, might not stand the test of time. Other fields of research, such as planetary studies, are not affected as much because they depend less on these preliminary brightness measurements.
Overall, it does not appear the more precise calibrations will change much of signficance, since most of the earliest observations were simply that, observations, not theoretical. Because the distance estimates remain largely unchanged however the theorists are left with the same conundrum: The age and apparent nature of the most distant objects does not seem to fit with what the theories had predicted Webb would see.