Tag: astronomy

Confirmed: Betelguese is brightening, as predicted

1:58 pm

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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Astronomers photograph baby stars in Orion

9:17 am

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

10:16 am

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.
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A baffling repeating fast radio burst

1:36 pm

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

8:23 am

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

12:02 pm

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

9:42 pm

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

3:36 pm

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

8:47 am

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

11:52 am

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

9:31 am

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?

9:32 am

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

9:20 am

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

9:33 am

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

9:41 am

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

9:24 am

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

9:22 am

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

10:02 pm

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

2:25 pm

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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Newly discovered repeating fast radio burst breaks rules

12:46 pm

The uncertainty of science: Astronomers have discovered the second fast radio burst that also repeats its bursts, and the discovery occurred in a place where such bursts were not expected to occur.

On 19th June 2019, eight telescopes from the European VLBI Network (EVN) simultaneously observed a radio source known as FRB 180916.J0158+65. This source was originally discovered in 2018 by the CHIME telescope in Canada, which enabled the team to conduct a very high resolution observation with the EVN in the direction of FRB 180916.J0158+65. During five hours of observations the researchers detected four bursts, each lasting for less than two thousandths of a second.

…With the precise position of the radio source the team was able to conduct observations with one of the world’s largest optical telescopes, the 8-m Gemini North on Mauna Kea in Hawaii. Examining the environment around the source revealed that the bursts originated from a spiral galaxy named SDSS J015800.28+654253.0, located half a billion light years from Earth. The bursts come from a region of that galaxy where star formation is prominent.

“The found location is radically different from the previously located repeating FRB, but also different from all previously studied FRBs”, explains Kenzie Nimmo, PhD student at the University of Amsterdam. “The differences between repeating and non-repeating fast radio bursts are thus less clear and we think that these events may not be linked to a particular type of galaxy or environment. It may be that FRBs are produced in a large zoo of locations across the Universe and just require some specific conditions to be visible.”

The actual locations of only five such bursts have been identified, so any generalization about their origin or nature seems premature anyway.

The American Astronomical Society (AAS) is having its semi-annual convention right now in Hawaii, which is why we are suddenly having a burst of astronomy-related press announcements.

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New evidence: dark energy might not exist

5:46 pm

The uncertainty of science: New evidence once again suggests that the assumptions that resulted in the invention of dark energy in the late 1990s might have been in error, and that dark energy simply might not exist.

New observations and analysis made by a team of astronomers at Yonsei University (Seoul, South Korea), together with their collaborators at Lyon University and KASI, show, however, that this key assumption is most likely in error. The team has performed very high-quality (signal-to-noise ratio ~175) spectroscopic observations to cover most of the reported nearby early-type host galaxies of SN Ia, from which they obtained the most direct and reliable measurements of population ages for these host galaxies. They find a significant correlation between SN luminosity and stellar population age at a 99.5% confidence level. As such, this is the most direct and stringent test ever made for the luminosity evolution of SN Ia. Since SN progenitors in host galaxies are getting younger with redshift (look-back time), this result inevitably indicates a serious systematic bias with redshift in SN cosmology. Taken at face values, the luminosity evolution of SN is significant enough to question the very existence of dark energy. When the luminosity evolution of SN is properly taken into account, the team found that the evidence for the existence of dark energy simply goes away.

…Other cosmological probes, such as CMB (Cosmic Microwave Background) and BAO (Baryonic Acoustic Oscillations), are also known to provide some indirect and “circumstantial” evidence for dark energy, but it was recently suggested that CMB from Planck mission no longer supports the concordance cosmological model which may require new physics. Some investigators have also shown that BAO and other low-redshift cosmological probes can be consistent with a non-accelerating universe without dark energy. In this respect, the present result showing the luminosity evolution mimicking dark energy in SN cosmology is crucial and is very timely.

There was also this story from early December, also raising questions about the existence of dark energy.

Bottom line: The data that suggested dark energy’s existence was always shallow with many assumptions and large margins of uncertainty. This research only underlines that fact, a fact that many cosmologists have frequently tried to sweep under the rug.

Dark energy still might exist, but it behooves scientists to look coldly at the data and always recognize its weaknesses. It appears in terms of dark energy the cosomological community is finally beginning to do so.

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Hubble captures giant galaxy

2:01 pm

Giant spiral galaxy imaged by Hubble
Click for full image.

Cool image time! The above image, cropped and reduced to post here, was compiled from images taken by the Hubble Space Telescope in 2018 of one of the largest known spiral galaxies.

One of the most photogenic is the huge spiral galaxy UGC 2885, located 232 million light-years away in the northern constellation, Perseus. It’s a whopper even by galactic standards. The galaxy is 2.5 times wider than our Milky Way and contains 10 times as many stars, about 1 trillion. This galaxy has lived a quiescent life by not colliding with other large galaxies. It has gradually bulked up on intergalactic hydrogen to make new stars at a slow and steady pace over many billions of years. The galaxy has been nicknamed “Rubin’s galaxy,” after astronomer Vera Rubin (1928 – 2016). Rubin used the galaxy to look for invisible dark matter. The galaxy is embedded inside a vast halo of dark matter. The amount of dark matter can be estimated by measuring its gravitational influence on the galaxy’s rotation rate.

This majestic spiral galaxy might earn the nickname the “Godzilla Galaxy” because it may be the largest known in the local universe. The galaxy, UGC 2885, is 2.5 times wider than our Milky Way and contains 10 times as many stars.

But it is a “gentle giant,” say researchers, because it looks like it has been sitting quietly over billions of years, possibly sipping hydrogen from the filamentary structure of intergalactic space. This fuels modest ongoing star birth at half the rate of our Milky Way. In fact, its supermassive central black hole is a sleeping giant, too; because the galaxy does not appear to be feeding on much smaller satellite galaxies, it is starved of infalling gas.

There are mysteries here, many of which we are as yet entirely unaware of yet.

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Betelguese fades a full magnitude

12:46 am

Long term observations of the red giant star Betelguese have found it to have faded a full magnitude in the past few months, dropping it from 6th brightest in the sky to the 21st.

You will see a lot of bad journalism related to this story, hyping the fact that Betelguese is considered one of the top nearby stars to someday in the far future go supernovae. However, the recent change in brightness is unlikely related to this and is nothing unusual, as the star fluctuates regularly.

The current faintness of Betelgeuse appears to arise from the coincidence of the star being near the minimum light of the ~5.9-yr light-cycle as well as near, the deeper than usual, minimum of the ~425-d period.

The star is definitely interesting, because it is so large (if placed in our solar system its surface would be around the orbit of Jupiter) and so defuse, more like a partly filled gasbag. However, the odds of it going supernovae in the near future is quite unlikely.

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Protesters continue to shut down TMT

5:12 pm

Mob rule: Though an agreement has been reached between the anti-telescope protesters and the mayor of the Big Island to move a tent blocking the access road to Mauna Kea, the deal also provided that no construction will proceed, even though the consortium that is building the Thirty Meter Telescope (TMT) has gotten legal permission to do so.

They agreed to move the so-called “kupuna tent,” referring to the Hawaiian word for elder, as part of a deal announced by Big Island Mayor Harry Kim.

In exchange, Kim promised protesters there will be no attempts to deliver construction equipment to the telescope site “anytime soon,” according to Kim’s offer letter to Noe Noe Wong-Wilson, one of the protest leaders who is considered a kupuna. “I, Mayor Kim give you my personal assurances that no attempt will be made to move TMT construction equipment up the mountain for a minimum of two months,” his letter said.

Legally Kim doesn’t really have the right to do this, unless Hawaii has decided to completely abandon the rule of law. Then again, Hawaii has decided to abandon the rule of law, as it now lets mobs, not the law, determine who can build where and when.

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The importance of small telescopes to science and civilization

10:58 am

The main cluster of telescopes, on Mount Lemmon
Largest cluster of telescopes on Mount Lemmon, six visible with three just out of view.

On December 11, 2019 I was kindly given a personal tour by Alan Strauss, director of the Mount Lemmon Sky Center, of the telescopes located on the mountaintops of the Santa Catalina Mountains overlooking Tucson. Strauss runs the educational outreach program for the University of Arizona astronomy department and the Steward Observatory, both of which operate the mountaintop facility.

The telescopes, numbering almost a dozen, are in two groups, two telescopes on the peak of Mount Bigelow and the rest clustered on the higher peak of Mount Lemmon. None are very gigantic by today’s standards, with their primary mirrors ranging in size from 20- to 61-inches. For comparison, the largest operating telescope in the world on the Canary Islands is 409 inches across. Hubble has a 94-inch mirror. And the new giant telescopes under design or being built have mirrors ranging from 842 inches (Giant Magellan) to 1,654 inches (European Extremely Large Telescope).

Thus, the small telescopes in the Santa Catalinas generally don’t make the news. They are considered passe and out-of-date, not capable of doing the kind of cutting edge astronomy that all the coolest astronomers hunger for.

Yet, without them, we likely would not have future astronomers. » Read more

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Scientists reject discovery of biggest known black hole

9:20 am

The uncertainty of science: In three new papers published this week astronomers have found that the announced discovery in early December of the biggest super-massive black hole ever found, 70 times the mass of the Sun, does not hold up.

In a recent study (a peer-reviewed study published Nov. 27), a team of scientists reported the discovery of the binary system LB-1, which contains a star and, according to the findings, a black hole companion 70 times the mass of our sun. This was major news, a stellar-mass black holes (black holes formed by the gravitational collapse of a star) are typically less than half that massive. But while the study, led by Jifeng Liu, of the National Astronomical Observatory of China (NAOC) of the Chinese Academy of Sciences, was exciting, it was also wrong.

Three new papers came out this week that reexamined the findings from Liu’s study, and these studies say that LB-1’s black hole isn’t actually all that massive.

The new papers find that a closer look at the data finds that it wasn’t doing what the initial researchers thought.

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Interacting galaxies

8:42 am

Interacting galaxies
Click for full image.

Astronomers using the 8-meter Gemini Telescope on Mauna Kea today released a new image of the Heron galaxy, showing its interaction with a nearby neighbor.

The new image captures the slow and intimate dance of a pair of galaxies some 160 million light-years distant and reveals the sparkle of subsequent star formation fueled by the pair’s interactions.

The two galaxies, astronomers have concluded, have already “collided” at least once. However, galactic collisions can be a lengthy process of successive gravitational encounters, which over time can morph the galaxies into exotic, yet unrecognizable forms. These galaxies, as in all galactic collisions, are engaged in a ghostly dance as the distances between the stars in each galaxy preclude actual stellar collisions and their overall shapes are deformed only by each galaxy’s gravity.

One byproduct of the turbulence caused by the interaction is the coalescence of hydrogen gas into regions of star formation. In this image, these stellar nurseries are revealed in the form of the reddish clumps scattered in a ring-like fashion in the larger galaxy (and a few in the smaller galaxy). Also visible is a dusty ring that is seen in silhouette against the backdrop of the larger galaxy. A similar ring structure is seen in this previous image from the Gemini Observatory, likely the result of another interacting galactic pair.

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New Hubble images of Comet 2I/Borisov

12:17 pm

Comet 2I/Borisov taken by Hubble prior to and at its closest approach to Sun
Click for full image.

Scientists today released new images taken by the Hubble Space Telescope of the interstellar object Comet 2I/Borisov. The image on the left was taken prior to the comet’s closest approach to the Sun, while the image on the right was taken during that closest approach. The vertical smeared object to the left in the earlier image is a galaxy that happened to be in the field of view. The blue color of both images is a false color to bring out details.

“Hubble gives us the best upper limit of the size of comet Borisov’s nucleus, which is the really important part of the comet,” said David Jewitt, a UCLA professor of planetary science and astronomy, whose team has captured the best and sharpest look at this first confirmed interstellar comet. “Surprisingly, our Hubble images show that its nucleus is more than 15 times smaller than earlier investigations suggested it might be. Our Hubble images show that the radius is smaller than half-a-kilometer. Knowing the size is potentially useful for beginning to estimate how common such objects may be in the solar system and our galaxy. Borisov is the first known interstellar comet, and we would like to learn how many others there are.”

The first image was taken from a distance of 203 million miles, while the second was taken from 185 million miles. Expect more images in late December, when the comet makes its closest approach to Earth at a distance of 180 million miles.

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TESS captures outburst from comet

5:42 pm

Wirtanen outburst

The space telescope TESS, designed to look for exoplanets by imaging one hemisphere of the sky repeatedly over a full year, also successfully captured in those images the full outburst from the comet 46P/Wirtanen that occurred on September 26, 2018.

The animation created from those images is to the right.

According to Farnham, the TESS observations of comet Wirtanen were the first to capture all phases of a natural comet outburst, from beginning to end. He noted that three other previous observations came close to recording the beginning of an outburst event. Observations of a 2007 outburst from comet 17P/Holmes began late, missing several hours of the initial brightening phase of the event. In 2017, observations of an outburst from comet 29P/Schwassmann-Wachmann 1 (SW1) concluded early, due to limitations on pre-scheduled observation time. And, while observations from the UMD-led Deep Impact mission captured an outburst from comet Tempel 1 in unprecedented detail in 2005, the outburst was not natural—created instead by the mission’s impactor module. However, the current observations are the first to capture the dissipation phase in its entirety, Farnham said.

Although Wirtanen came closest to Earth on December 16, 2018, the outburst occurred earlier in its approach, beginning on September 26, 2018. The initial brightening of the outburst occurred in two distinct phases, with an hour-long flash followed by a more gradual second stage that continued to grow brighter for another 8 hours. This second stage was likely caused by the gradual spreading of comet dust from the outburst, which causes the dust cloud to reflect more sunlight overall. After reaching peak brightness, the comet faded gradually over a period of more than two weeks. Because TESS takes detailed, composite images every 30 minutes, the team was able to view each phase in exquisite detail.

The data from TESS is likely going to overwhelm the astronomy community for years.

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