Tag Archives: astronomy

TMT protesters abandon camp due to Wuhan virus fears

The protesters who have been blocking construction of the Thirty Meter Telescope (TMT) on Mauna Kea in Hawaii have abandoned their camp due to fears of COVID-19.

Though this gives the consortium an opportunity to begin construction, don’t expect it. Based on info I’ve gotten from within the astronomy community (most of which is liberal and thus very focused on identity politics), the consortium that wants to build TMT is torn over these protests, with many astronomers sympathetic to the protesters’ false claims of bigotry and religious oppression.

TMT will not be built in Hawaii. Whether it is built at all remains an open question.

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New radio telescope discovers many new Fast Radio Bursts

A new radio telescope in Canada, designed to detect the mysterious and as-yet unexplained Fast Radio Bursts (FRB), has in the past year raised the total of known FRBs from 30 to 700, including nine repeating bursts.

This confirms an earlier very preliminary analysis that there were two different types of bursts, those that repeat and those that don’t.

Warning: It is very dangerous to take these results too seriously. A lot of uncertainty exists, including some basic facts about the bursts.

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Webb telescope further delayed by COVID-19

As part of its decision to shut down most of the agency’s operations due to fear of the COVID-19 virus, NASA’s has suspended all work on the James Webb Telescope, further delaying this much delayed space telescope.

The follow-on to the popular Hubble Space Telescope [Ed: a NASA lie that is not true], years late and billions over budget, it was on track for launch in March 2021, though some NASA officials were hinting there might be another delay. Today’s action almost certainly assures it. “The James Webb Space Telescope team … is suspending integration and testing operations. Decisions could be adjusted as the situation continues to unfold over the weekend and into next week. The decision was made to ensure the safety of the workforce. The observatory remains safe in its cleanroom environment.” — NASA

I must repeat this incessantly, as it appears too many modern space reporters are very ignorant about their own field. Webb is not a” follow-on to Hubble.” Astronomers made the decision in the late 1990s to build an infrared space telescope instead, which is what Webb is. For more than a decade they, and NASA, lied to the public about this, claiming Webb was a better version of Hubble, in order to garner support for building Webb.

I have been calling NASA on lie this since 2008, when I wrote The Universe in a Mirror, which I think eventually forced the agency to stop doing it. It is shameful however for a reporter now, in 2020, to still spread it.

As for Webb, this decision by NASA will certainly delay it again. The project is already fourteen years behind schedule, with its budget ballooning from $500 million to about $10 billion. All told, a perfect example of government in action.

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Comet C/2019 ATLAS brightening

Comet ATLAS, discovered in 2019 by a telescopic survey looking for near Earth asteroids, is brightening more than expected as it approaches the Sun, and could by May be visible to the naked eye.

Jonathan Shanklin, Director of the British Astronomical Association’s Comet Section, reports that the current comet, C/2019 Y4, brightened quite rapidly in mid February, and adds “as of March 11 there is no sign of a slowdown in the rate of brightening. It is already visible in large binoculars . . . The uncertainty in brightness at the time of perihelion is large, though the worst case indicator is 2nd magnitude. It will remain well placed for UK observers into May and could become a prominent object.”

If 2nd magnitude is the dimmest they presently expect, this comet will be one of the brightest objects in the sky come May. Stay tuned!

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An exoplanet where it rains iron

Astronomers have discovered an exoplanet 640 light years away hot enough for iron to be vapor in the atmosphere and to condense out as rain.

The high-resolution spectrum reveals lots of iron vapor within the sliver of atmosphere undergoing the transition from day to night. However, this iron vapor signature is missing from the sliver of atmosphere transitioning from night to day. The astronomers think this happens because strong winds push iron vapor to the nightside, where it cools and condenses into clouds.

“This planet has a twilight zone at a temperature close to the iron condensation temperature,” Ehrenreich explains, “so the change in atmospheric composition (with iron vs. without iron) is occurring right where we are able to observe.”

Because the planet is a gas giant, there’s no surface onto which the droplets can fall, says coauthor Nuno Santos (University of Porto, Portugal). But the planet’s gravity likely pulls the clouds downward, enveloping the nightside in iron fog. The global winds then push the clouds and fog onto the dayside, where the vaporization-condensation cycle repeats again.

Very exotic, and alien, and I guarantee it is probably far more alien than we so far can guess.

You can find out more in this second more detailed article.

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Astronomers more precisely estimate the diameter of neutron stars

Using several different techniques, astronomers now estimate that the typical neutron star will have a diameter of 11 kilometers, or about 7 miles.

What is significant about this new estimate is that if that neutron star happens to be orbiting a black hole and get pulled into it, it will be swallowed whole instead of being ripped apart.

Their results, which appeared in Nature Astronomy today, are more stringent by a factor of two than previous limits and show that a typical neutron star has a radius close to 11 kilometers. They also find that neutron stars merging with black holes are in most cases likely to be swallowed whole, unless the black hole is small and/or rapidly rotating. This means that while such mergers might be observable as gravitational-wave sources, they would be invisible in the electromagnetic spectrum.

In other words, such cataclysmic events would be largely invisible to observers.

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Japan suspends funding to TMT

The Japanese government has confirmed that it has suspended payment of its annual contribution to the budget of the Thirty Meter Telescope (TMT) because of the project’s inability to begin construction on Mauna Kea in Hawaii.

Japanese astronomers strongly prefer placing TMT on Mauna Kea because it is relatively close to Japan, unlike the proposed replacement site in the Grand Canary Islands in the Atlantic.

I would say this is the next nail in the coffin for TMT in Hawaii. The National Science Foundation (NSF) has money to fund construction of a big telescope for U.S. astronomers, but has not been able to decide on whether to give the money to TMT, or to the Giant Magellan Telescope (GMT), already under construction in Chile, or to both.

Astronomers have been lobbying for dual funding, using the argument that the two telescopes are in the opposite north and south hemispheres. Moving TMT to the Grand Canaries, at a higher latitude than Hawaii, strengthens this argument. With the apparent exit of Japan it could be that the way is now cleared to give up on Hawaii and for TMT to make the move to a more welcoming site.

Hawaii’s protesters, supported by the state’s Democratically-controlled government, will of course celebrate. What they will be celebrating however will be the death-knell of science in Hawaii.

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Birth of a planetary nebula

Beginnings of a planetary nebula

Astronomers, using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile have created a multi-spectral radio image of a dying star in its very initial stages of becoming a beautiful planetary nebula.

[Using ALMA,] the team obtained a very detailed view of the space around W43A. “The most notable structures are its small bipolar jets,” says Tafoya, the lead author of the research paper published by the Astrophysical Journal Letters. The team found that the velocity of the jets is as high as 175 km per second, which is much higher than previous estimations. Based on this speed and the size of the jets, the team calculated the age of the jets to be less than a human life-span.

“Considering the youth of the jets compared to the overall lifetime of a star, it is safe to say we are witnessing the ‘exact moment’ that the jets have just started to push through the surrounding gas,” explains Tafoya. “The jets carve through the surrounding material in as little as 60 years. A person could watch their progress throughout their lifetime.”

Over time those jets, thought to be caused by the interaction of the central star with a smaller secondary star that orbits it, will interact increasingly with the surrounding gas. The result will be a quite spectacular planetary nebula.

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Review of Kepler data uncovers seventeen more possible exoplanets

Worlds without end: In reviewing the entire Kepler database of 200,000 stars, scientists have found seventeen more candidate exoplanets, including one only 1.5 times the mass of the Earth that is also in the habitable zone.

From the paper’s abstract:

We present the results of an independent search of all ~200,000 stars observed over the four year Kepler mission (Q1–Q17) for multiplanet systems, using a three-transit minimum detection criterion to search orbital periods up to hundreds of days. We incorporate both automated and manual triage, and provide estimates of the completeness and reliability of our vetting pipeline. Our search returned 17 planet candidates (PCs) in addition to thousands of known Kepler Objects of Interest (KOIs), with a 98.8% recovery rate of already confirmed planets. We highlight the discovery of one candidate, KIC-7340288 b, that is both rocky (radius $\leqslant 1.6{R}_{\oplus }$) and in the Habitable Zone (insolation between 0.25 and 2.2 times the Earth’s insolation). Another candidate is an addition to the already known KOI-4509 system.

I must emphasize that these are candidate exoplanets, meaning their existence has not been confirmed by other observations, and could very well turn out to be false positives.

Still, that this independent review matched the previous list of Kepler candidates within 98.8% means that the list of exoplanet candidates from Kepler is solid and worth further study. With thousands of candidates, however, that further study is likely going to take a very long time. And the backlog will be growing significantly with the many thousands of additional exoplanet candidates expected to be found by TESS.

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First image of possible asteroid in orbit around the Earth

asteroid orbiting the Earth?
Click for full image.

The Gemini telescope in Hawaii has produced the first image of what might be only the second asteroid ever discovered in orbit around the Earth.

The newly discovered orbiting object has been assigned the provisional designation 2020 CD3 by the International Astronomical Union’s Minor Planet Center. If it is natural in origin, such as an asteroid, then it is only the second known rocky satellite of the Earth ever discovered in space other than the Moon. The other body, discovered in 2006, has since been ejected out of Earth orbit. 2020 CD3 was discovered on the night of 15 February 2020 by Kacper Wierzchos and Teddy Pruyne at the Catalina Sky Survey operating out of the University of Arizona’s Lunar and Planetary Laboratory in Tucson, Arizona.

The photo to the right has been cropped to post here. The streaks are stars, since the telescope was tracking the asteroid in an attempt to cull the most resolution of it from the image.

This object is only a few yards across, and could very well be a piece of space junk from a mission launched many decades ago. It is also not in a stable orbit around the Earth, and is expected to be ejected from that orbit in April.

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Confirmed: Betelguese is brightening, as predicted

More observations have now confirmed that Betelguese is once again brightening, as predicted.

Photometry secured over the last ~2 weeks shows that Betelgeuse has stopped its large decline of delta-V of ~1.0 mag relative to September 2019. The star reached a mean light minimum of = 1.614 +/- 0.008 mag during 07-13 February 2020. This is approximately 424+/-4 days after the last (shallower: V ~ +0.9 mag) light minimum was observed in mid-December 2018. Thus the present fading episode is consistent with the continuation of the persistent 420-430 day period present in prior photometry.

In other words, the star’s dimming, though deeper than earlier dips, was right in line with a well-known variation cycle. While absolutely worth close observation and study, the data now strongly suggests that this is relatively normal behavior for this aging red giant star. It will likely go supernova sometime in the future, not likely now.

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As predicted, Betelguese’s dimming has ceased

As predicted by astronomers, Betelguese’s dimming has ceased and has even begun to brighten slightly in the past week.

The graph here and at the link shows the uptick clearly. As this was exactly what was expected if the star followed its past cyclical patterns, this strongly suggests that we will not see any supernovae from the star anytime in the near future.

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Astronomers photograph baby stars in Orion

Some of the baby stars surveyed
Click for full image.

Astronomers using two radio telescopes have created multi-wavelength radio images of 300 protoplanetary disks, or proplyds, found in the star forming region in the constellation Orion. The image to the right shows only a small sampling of the proplyds imaged.

“This survey revealed the average mass and size of these very young protoplanetary disks,” said John Tobin of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, and leader of the survey team. “We can now compare them to older disks that have been studied intensively with [the radio telescope] ALMA as well.”

What Tobin and his team found, is that very young disks can be similar in size, but are on average much more massive than older disks. “When a star grows, it eats away more and more material from the disk. This means that younger disks have a lot more raw material from which planets could form. Possibly bigger planets already start to form around very young stars.”

Of the disks photographed, four appear to be extremely young, probably less than ten thousand years, because of their very blobby and irregular shape.

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Images reveal changes in Betelgeuse’s shape as it has been dimming

Betelgeuse dimmed
Click for full image.

Using the Very Large Telescope in Chile astronomers have produced before and after images of the red giant Betelgeuse, showing the changes to the star in the past year as it has dimmed by about 36%.

The image to the right, cropped and reduced to post here, was taken in December and shows the star in its dimmed state. Below the fold is a short video that compares this image with a photograph taken in January 2019. The star was then more spherical and evenly bright.

Betelgeuse’s misshaped profile and uneven brightness is not actually a new thing. See for example this 2017 image, where I noted that the bulge on the star’s side suggested “that continuous observations would reveal the outer atmosphere waxing and waning almost like the stuff inside a lava lamp.” The star is a giant gasbag that in the past has frequently been observed with dark patches on its surface and a sense that it is not always spherical. Those changes however have not occurred with such a significant dimming, a full magnitude

In late December I had posted a story noting that the dimming appeared to be expected, caused by the alignment of two different regular fluctuations of brightness, one 5.9 years long and the other 0.5 year long. It was expected that the star would begin brightening again.

Right now astronomers estimate that the low point in these cycles will occur on approximately February 21st. If the star begins to brighten following that date it would confirm that this dimming is just part of its cycles. If not, then it could be that we are in the preliminaries to a supernova event that would probably make Betelgeuse bright enough to be seen during the day.
» Read more

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A baffling repeating fast radio burst

Astronomers are baffled by a fast radio burst, a phenomenon that is a mystery in its own right, that also repeats its bursts in what appears to be a regular pattern.

Researchers looking at data from the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project (CHIME/FRB) first spotted this FRB, known as FRB 180916.J0158+65, in 2019. In January 2020, they published a paper in the journal Nature that reanalyzed old data and found more than one burst from FRB 180916.J0158+65. They traced this FRB back to a relatively nearby spiral galaxy. What’s new in this latest paper, published Feb. 3 to the arXiv database, is the regular pattern in the bursts. The FRB, they found, goes through four-day cycles of regular activity, bleating out radio waves into space on an almost hourly basis. Then it goes into a 12-day period of silence. Sometimes the source seems to skip its usual four-day awake periods, or lets out only a single burst. CHIME/FRB is able to watch the FRB only some of the time, they noted, so it’s likely the detector misses many FRBs during the awake period.

At present they have no idea what is causing the pattern, other than a realization that it defies all the theories for explaining the previously discovered fast radio bursts.

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An update on Comet 2I/Borisov

Link here.

Overall, this second known interstellar object to pass through the solar system appears to be a very typical comet. They have found however that its nucleus is much smaller than at first thought, only 200 to 500 meters across, which means that radiation pressure from the Sun could cause its rotation to spin up, with the possibility that this spin could get fast enough to cause the comet to break up.

The comet made its closest approach to the Sun in December, and will spend the next year-plus flying outward to beyond Saturn.

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Successful first light for CHEOPS space telescope

The science team for Europe’s exoplanet-hunting CHEOPS space telescope announced today that the telescope has successfully obtained its first pictures, and that all appears to be working correctly.

Preliminary analysis has shown that the images from CHEOPS are even better than expected. However, better for CHEOPS does not mean sharper as the telescope has been deliberately defocused. This is because spreading the light over many pixels ensures that the spacecraft’s jitter and the pixel-to-pixel variations are smoothed out, allowing for better photometric precision. “The good news is that the actual blurred images received are smoother and more symmetrical than what we expected from measurements performed in the laboratory,” says Benz. High precision is necessary for CHEOPS to observe small changes in the brightness of stars outside our solar system caused by the transit of an exoplanet in front of the star. Since these changes in brightness are proportional to the surface of the transit planet, CHEOPS will be able to measure the size of the planets. “These initial promising analyses are a great relief and also a boost for the team,” continues Benz.

I suspect the planned fuzziness of their images is why the press release did not include them.

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Two defunct satellites barely miss each other

Missed it by that much: According to the US Space Command, two defunct satellites, one the first infrared space telescope ever launched and the other a military technology test satellite, apparently did not collide tonight, barely missing each other.

Prior to impact it was estimated they could get within as little as 40 feet. Since the military satellite had booms 60 feet long, the possibility of impact was quite real, especially because there was also a margin of error in the calculations and the two satellites were traveling almost 33,000 mph relative to each other. Had they hit each other the cloud of debris would have caused enormous problems, as the pieces would have been a threat to many other satellites presently in orbit.

Fortunately they missed each other. The problem of many such defunct satellites and upper stages and general space junk still exists however. Someone could make some good money providing a service to clean this stuff up. I suspect governments would be willing to pay to have it done.

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First images from Inouye Solar Telescope

Close-up of the Sun by Inouye Telescope

Scientists have released the first images of the Sun taken by the new Daniel K. Inouye Solar Telescope on the island of Maui in Hawaii.

The image to the right, cropped to post here, is today’s released image, a close-up of the Sun’s surface granular structure, with each cell about the size of Texas.

Right now most of the telescope’s instruments are not yet on line. It is expected the telescope will become fully operational in July.

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GAO warns of more Webb delays

The race to the bottom between Webb and SLS continues! A new Government Accountability Office (GAO) report warns that there is high likelihood that NASA will not meet its March 2021 target launch date for the James Webb Space Telescope.

The report noted that the program performed an updated joint confidence level analysis of the mission’s cost in schedule in October. “Because of schedule delays resulting from technical challenges coupled with remaining risks faced by the project, the analysis assessed only a 12 percent confidence level for the project’s ability to meet the March 2021 launch readiness date,” the report stated.

NASA missions usually set cost and schedule estimates at the 70% confidence level. Using that metric, the launch would likely take place in July 2021, a delay of four months, according to the report.

Webb is now more than a decade behind schedule, with its budget ballooning from $1 billion to just under $10 billion. These facts essentially wiped out almost all new astronomical projects in the 2010s.

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Two abandoned satellites might collide

According to a company that monitors objects in low Earth orbit, two abandoned satellites might actually collide on January 29..

The two satellites, NASA’s IRAS space telescope and the experimental U.S. Naval Research Lab satellite GGSE-4, will swing past each other at 6:39 p.m. EST at an altitude of about 559 miles in the skies above Pittsburgh, Pennsylvania. They’ll be hurtling along their orbit at a relative velocity of about 32,880 miles per hour and could swing within 50 feet of each other.

LeoLabs noted that, at the time of the tweet, the odds of a collision were about 1 in 100 and said the relatively large size of the two spacecraft increased the risk of a collision.

IRAS was the first infrared space telescope ever launched, and operated for ten months after its launch in 1983. The other spacecraft was a National Security Agency test satellite of surveillance technology.

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Strange things at center of Milky Way

Astronomers have discovered an additional four more weird objects orbiting the supermassive black hole, dubbed Sagittarius A* (pronounced A-star) for a total of six, all of which display behavior that is inexplicable.

Part of a new class called G objects, they look compact most of the time and stretch out when their orbits bring them closest to the black hole. Those orbits range from about 100 to 1000 years. “These objects look like gas and behave like stars,” says Andrea Ghez, director of the Galactic Centre Group at the University of California, Los Angeles (UCLA) and co-author of a paper in the journal Nature.

The new discoveries are known simply as G3 to G6. G1 was discovered by Ghez’s research group back in 2005, and G2 by astronomers in Germany in 2012. “The fact that there are now several of these objects observed near the black hole means that they are, most likely, part of a common population,” says co-author Randy Campbell, from the Keck Observatory in Hawaii.

It is not surprising that the intense gravitational field of Sagittarius A* rips these objects into elongated stretched objects as their orbits bring them close to the black hole. What is very very puzzling is their apparent ability to spring back to compact form as their orbits take them away from the black hole.

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A second exoplanet orbiting Proxima Centauri?

Worlds without end: Astronomers think they have found evidence of a second exoplanet orbiting the nearest star, Proxima Centauri.

The planet, a super-Earth called Proxima Centauri c (Proxima c for short), has at least six times more mass than Earth and orbits its star every 5.2 years.

…“Stars like Proxima Centauri are rather restless and continuously present eruptions and spots on their surface, which make the detection of a planetary-induced oscillation very complicated,” says coauthor Fabio Del Sordo (University of Crete and Foundation for Research and Technology-Hellas in Heraklion, Greece). Because the observations span almost two decades, the scientists have confidently ruled out those sources of noise, but they caution that follow-up observations are needed to confirm that the signal comes from a planet.

There is a lot of uncertainty here, requiring an independent confirmation of this result. It would not be surprising if this exoplanet vanished when others took a look, finding it a creation not of a periodic gravitation wobble but of the random fluctuations of the star itself.

If it does exist, it will not likely be a place where life exists. Too far from this very dim red dwarf star to get enough energy. However, as a super-Earth it might someday in the far future be a great mining world.

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Spitzer SpaceTelescope shutdown in a week

After sixteen years in orbit, NASA will shut down the Spitzer Space Telescope on January 22, 2020,

The telescope is still functional in a somewhat limited manner but NASA wishes to save the annual budget of $14 million to operate it. Moreover, it will become redundant and significantly superseded once the infrared James Webb Space Telescope launches and becomes operational next year.

NASA had hoped a private organization would take over Spitzer’s operation, but apparently got no takers.

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First asteroid discovered that circles Sun closer than Venus

Astronomers have detected the first asteroid circling the Sun in an orbit that lies entirely inside Venus’s orbit.

In addition to being the first known asteroid with this orbit, the space rock, called 2020 AV2, has the smallest aphelion, or distance from the sun, of any known natural object in the solar system, excluding Mercury. Moreover, by traveling around the sun in a mere 151 days, 2020 AV2 has the shortest orbital period of any known asteroid, according to The Virtual Telescope Project, an online observatory based in Italy.

The reason this is a first is because it is very hard to find such small objects orbiting closer to the Sun than Earth. The glare of the Sun limits what can be spotted. This fact is also why the scientists are unsure of the size of 2020 AV2.

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More superEarth exoplanets found circling nearby stars

Worlds without end: Among a new bunch of thirteen exoplanets, astronomers have discovered two more superEarth-sized exoplanets circling nearby red dwarf stars.

The two potentially habitable planets are orbiting GJ180 and GJ229A, which are among the nearest stars to our own Sun, making them prime targets for observations by next-generation space- and land-based telescopes. They are both super-Earths with at least 7.5 and 7.9 times our planet’s mass and orbital periods of 106 and 122 days respectively.

The Neptune-mass planet—found orbiting GJ433 at a distance at which surface water is likely to be frozen—is probably the first of its kind that is a realistic candidate for future direct imaging. “GJ 433 d is the nearest, widest, and coldest Neptune-like planet ever detected,” Feng added.

For a lot of reasons it is likely that life as we know it probably does not exist on these planets. Nonetheless, their close proximity makes it possible to study them, and since we have no such planets in our own solar system they can teach us a lot about planetary formation and evolution.

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Arecibo shut temporarily due to earthquakes

The Arecibo Observatory in Puerto Rico has suspended all operations temporarily because of the swarm of earthquakes that have hit the island in the past two weeks.

The strongest of those quakes was a 6.4 temblor early in the morning of Tuesday (Jan. 7). An initial survey conducted by drone after that event found no damage to the massive radio dish or the equipment above it, an Arecibo Observatory representative said here at the 235th meeting of the American Astronomical Society on Tuesday (Jan. 7).

However, safety protocols mean that observatory personnel can’t examine the dish or its accessories until the ground stops shaking, and it’s difficult to predict when that will happen.

The observatory was about to embark on a yearlong refitting to repair damage caused by Hurricane Maria in 2017. They have set January 10th as a tentative reopen date.

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Webb telescope remains on schedule for March 2021 launch

Good news: According to NASA and Northrop Grumman officials, the James Webb Space Telescope remains on schedule for its March 2021 launch by an Ariane 5 rocket.

This might be the first update on Webb in years where no new delays were announced. Instead, the Space Telescope Science Institute in Maryland, which will manage the telescope, is preparing to release in two weeks its first call for research proposals.

Proposals will be due May 1, with the institute making selections later in the summer. …[I]nstitute officials said they expect to receive 1,000 to 1,600 proposals, seeking some fraction of the 6,000 hours of observing time that will be available in that initial round of observations. About 300 proposals will be selected for Cycle 1, which will begin once spacecraft commissioning is complete about six months after launch.

Let us all pray that all goes well during launch and spacecraft deployment.

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TESS finds its first Earth

Worlds without end: TESS has discovered its first Earth-sized planet, orbiting a M dwarf star within the habitable zone.

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.”

We could also give this story the subhead “the uncertainty of science.” Note how a revision of the star’s mass changed the planet’s. Though I am sure they have improved their estimate of the star, this error illustrates how easy it is to get a final astronomical conclusion wrong. There are always a lot of assumptions long the way, any one of which could have a margin of error significant enough to change the final result.

In other TESS news, the space telescope has also found an exoplanet orbiting a stellar binary system of two stars.

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Astronomers predict nova outburst later this century

Based on the rate of material spiraling from one star to another in a nearby stellar binary system, astronomers now predict that the two stars will merge sometime between 2067 and 2099, producing a nova that will among the brightest stars in the sky, visible to the naked eye for about a month.

From the press release:

Currently, the faint star V Sagittae, V Sge, in the constellation Sagitta, is barely visible, even in mid-sized telescopes. However, around the year 2083, this innocent star will explode, becoming as bright as Sirius, the brightest star visible in the night sky. During this time of eruption, V Sge will be the most luminous star in the Milky Way galaxy. … “We now have a strong prediction for the future of V Sge,” said Professor Emeritus Bradley E. Schaefer, LSU Department of Physics & Astronomy. “Over the next few decades, the star will brighten rapidly. Around the year 2083, its accretion rate will rise catastrophically, spilling mass at incredibly high rates onto the white dwarf, with this material blazing away. In the final days of this death-spiral, all of the mass from the companion star will fall onto the white dwarf, creating a supermassive wind from the merging star, appearing as bright as Sirius, possibly even as bright as Venus.”

“V Sge is exponentially gaining luminosity with a doubling time scale of 89 years,” said Frank. “This brightening can only result with the rate of mass falling off the normal companion star increasing exponentially, ultimately because the binary orbit is in-spiraling rapidly.”

“In anticipation of this fast decaying of the orbit, the fate of V Sge is sealed,” stated Schaefer. “The critical and simple physics are derived from V Sge having the companion star being much more massive than the white dwarf star, so forcing the rate of mass transfer to rise exponentially. Anticipating the next few decades, V Sge will in-spiral at a rapid pace with increasing brightness. Inevitably, this in-spiral will climax with the majority of the gas in the normal star falling onto the white dwarf, all within the final weeks and days. This falling mass will release a tremendous amount of gravitational potential energy, driving a stellar wind as never before seen, and raise the system luminosity to just short of that of supernovae at peak.”

This explosive event will have peak brightness over a month, with two stars merging into one star. The end result of the merger will produce a single star with a degenerate white dwarf core, a hydrogen-burning layer, surrounded by a vast gas envelope mostly of hydrogen.

The press release has not yet been posted, but the press materials for the announcement can be found here.

If their hypothesis turns out to be true, it will be the first such event ever predicted.

Note that they are not predicting a supernova, an event caused by a variety of ways (all related to the death of a star). This is a less spectacular nova event, though because of its relative nearness will be very bright in our sky.

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