Connect with us

In 2018, astronomers detected an exoplanet around the star 40 Eridani. It’s about 16 light-years away in the constellation Eridanus. The discovery generated a wave of interest for a couple of reasons. Not only is it the closest Super-Earth around a star similar to our Sun, but the star system is the fictional home of Star Trek’s Vulcan science officer, Mr. Spock.

It’s always fun when a real science discovery lines up with science fiction.

Eridani’s other name is HD 26965, and it’s actually a triple-star system. Astronomers discovered the system’s lone planet, Eridani b, using the radial velocity method. Orbiting planets tug on their stars, and the star’s movement creates a change in its spectrum. Astronomical telescopes with spectrometers can detect the changes.

Jian Ge, an astronomy professor at the University of Florida, led the study that presented the discovery in 2018. At the time, Ge said in a press release, “The new planet is a ‘super-Earth’ orbiting the star HD 26965, which is only 16 light years from Earth, making it the closest super-Earth orbiting another Sun-like star. The planet is roughly twice the size of Earth and orbits its star with a 42-day period just inside the star’s optimal habitable zone.”

A super-Earth in the habitable zone around a Sun-similar star ‘only’ 16 light-years away is an intriguing discovery. Its link with a beloved Star Trek character gave the discovery wings, and word spread.

However, in the intervening years, follow-up observations have not confirmed Eridani b’s existence. A 2021 study suggested that the change in the star’s spectrum was a false positive. Now, a new study says that the exoplanet fondly named Vulcan does not exist.

The study is “The Death of Vulcan: NEID Reveals That the Planet Candidate Orbiting HD 26965 Is Stellar Activity.” It’s published in The Astronomical Journal, and the lead author is Abigail Burrows, an astronomer at Dartmouth College.

“We revisit the long-studied radial velocity (RV) target HD 26965 using recent observations from the NASA-NSF “NEID” precision Doppler facility,” Burrows and her co-authors write. After a deeper, line-by-line analysis of the radial velocity data, “… we demonstrate that the claimed 45-day signal previously identified as a planet candidate is most likely an activity-induced signal.”

Activity-induced signal means that the signal comes from the star’s activity, not from the external tug of an exoplanet.

Vulcan’s initial detection was based on data from the Dharma Planet Survey (DPS.) DPS monitored about 150 nearby Sun-like stars for changes in their spectra. Data from the Keck Telescope and the HARPS planet-finding spectrograph also contributed to the discovery.

When the planet was detected in 2018, the discoverers recommended caution. They presented the data as they collected it, along with their best interpretation. That’s standard in science, and they were careful in calling it a candidate planet. In their paper, they also discussed “the possibility that the RV signal is actually produced by stellar rotation modulated activity.” That activity could be sunspots, convection irregularities, or other things.

But in the end, they concluded that what they were seeing was likely a planet.

“By carefully examining the RV data in the active and quiet phases of the star, and after carefully considering all possible stellar activity sources, we concluded that the coherent signal seen from HD 26965 is most likely from a planet, with some RV noise contributed by stellar activity,” the authors wrote in the 2018 paper.

The rest of us were happy to agree because finding a super-Earth around a nearby Sun-like star is the kind of thing we hope to find.

“Men sometimes see exactly what they wish to see.”

-Spock of Vulcan

Sadly for Vulcan, the newest research shows that the stellar activity isn’t noise. It accounts for the entire signal.

The new results are based on NEID, the NN-explore Exoplanet Investigations with Doppler spectroscopy. It’s a high-resolution spectrometer attached to the WIYN (Wisconsin-Indiana-Yale-NOIRLab) telescope at Kitt Peak Observatory. The researchers used NEID to capture 63 spectra from Eridani over a six-month period.

NEID revealed a lot of information about the star, including things like contrast and radial velocity. Together, NEID data paints a more complete picture of the star and its activity. In this new work, Burrows and her co-researchers showed that all of this activity lines up with the star’s 42-day rotation period.

“All measurements show a strong signal at or near the 42-day stellar rotation period,” they write.

Continue Reading

Frontier Adventure

Hubble’s Back, but Only Using One Gyro

Hubble gyros

The Hubble Space Telescope has experienced ongoing problems with one of its three remaining gyroscopes, so NASA has decided to shift the telescope into single gyro mode. While the venerable space telescope has now returned to daily science operations, single gyro mode means Hubble will only use one gyro to maintain a lock on its target. This will slow its slew time and decrease some of its scientific output. But this plan increases the overall lifetime of the 34-year-old telescope, keeping one gyro in reserve. NASA is also troubleshooting the malfunctioning gyro, hoping to return it online.

Last week, NASA said that the telescope and its instruments are stable and functioning normally.

Gyroscopes help the telescope orient itself in space, keeping it stable to precisely point at astronomical targets in the distant Universe. Hubble went into safe mode back in November 2023, and then again in April and May 2024 due to the ongoing issue, where the one gyro had been increasingly returning faulty readings.

Hubble gyros 1
The end of a Hubble gyro reveals the hair-thin wires known as flex leads. They carry data and electricity inside the gyro. Credit: NASA

Going in to safe mode suspends science operations, and in the meantime, engineers tried to troubleshoot to figure out why the gyro experiencing the fault-producing issues and doing work-arounds to get the telescope up and running again. The most recent last safe-mode event in May led the Hubble team to transition from a three-gyro operating mode to observing with only one gyro. This enables more consistent science observations while keeping the other operational gyro available for future use.

Launched in 1990, Hubble has more than doubled its expected design lifetime, providing stunning images and scientific discoveries that have changed our understanding of the Universe and re-written astronomy textbooks.

During its 34-year history, Hubble has had eight out of 22 gyros fail due to a corroded flex lead, which are thin (less than the width of a human hair) metal wires, that carry power in, and data out, of the gyro. The flex leads pass through a thick fluid inside the gyro and over time, the flex leads begin to corrode and can physically bend or break.

mike good hubble sm4
With his feet firmly anchored on the shuttle’s robotic arm, astronaut Mike Good maneuvers to retrieve the tool caddy required to repair the Space Telescope Imaging Spectrograph during the final Hubble servicing mission in May 2009. Periodic upgrades have kept the telescope equipped with state-of-the-art instruments, which have given astronomers increasingly better views of the cosmos. Credits: NASA

Thankfully, for the first 18 years of Hubble’s life in space, the telescope had the advantage of being able to be serviced and upgraded by space shuttle astronauts. For example, in 1999, four out of six gyros had failed, with the last one failing about a month before a servicing mission was scheduled to replace them (and do other upgrades to the telescope). This meant Hubble sat in safe mode waiting for the space shuttle and astronauts to arrive.

When the final planned Hubble servicing mission was (temporarily) canceled following the space shuttle Columbia disaster, engineers developed and inaugurated a two-gyro mode to prolong Hubble’s life. The mission was reinstated after outcry from scientists and the public, and so NASA figured out a way to mitigate the risks of flying the space shuttle. Servicing Mission 4 replaced all six gyros one last time in 2009, but it has been running on three since 2018. The
Did you miss our previous article…

Continue Reading

Frontier Adventure

A New Way to Prove if Primordial Black Holes Contribute to Dark Matter

Collapse Simulation 580x580 1

The early Universe was a strange place. Early in its history—in the first quintillionth of a second—the entire cosmos was nothing more than a stunningly hot plasma. And, according to researchers at the Massachusetts Institute of Technology (MIT), this soup of quarks and gluons was accompanied by the formation of weird little primordial black holes (PHBs). It’s entirely possible that these long-vanished PHBs could have been the root of dark matter.

MIT’s David Kaiser and graduate student Elba Alonso-Monsalve suggest that such early super-charged black holes were very likely a new state of matter that we don’t see in the modern cosmos. “Even though these short-lived, exotic creatures are not around today, they could have affected cosmic history in ways that could show up in subtle signals today,” Kaiser said. “Within the idea that all dark matter could be accounted for by black holes, this gives us new things to look for.” That means a new way to search for the origins of dark matter.

Dark matter is mysterious. No one has directly observed it yet. However, its influence on regular “baryonic” matter is detectable. Scientists have many suggestions for what dark matter could be, but until they can observe it, it’s tough to tell what the stuff is, exactly. Black holes could be likely candidates. But the mass of all the observable ones isn’t enough to account for the amount of dark matter in the cosmos. However, there may be a connection to black holes after all.

Black Holes Through Cosmic Time

Most of us are familiar with the idea of at least two types of black holes: stellar-mass and supermassive. There is also a population of intermediate-mass black holes, which are rare. The stellar-mass objects form when massive stars explode as supernovae and collapse to form black holes. These exist throughout many galaxies. The supermassive ones aggregate many millions of solar masses together. They form “hierarchically” from smaller ones and exist in the hearts of galaxies. The intermediate-mass ones probably form hierarchically as well and could be a hidden link between the other two types.

An image based on a supercomputer simulation of the cosmological environment where primordial gas undergoes the direct collapse to a black hole. Credit: Aaron Smith/TACC/UT-Austin.
An image based on a supercomputer simulation of the cosmological environment where primordial gas undergoes the direct collapse to create black holes. Credit: Aaron Smith/TACC/UT-Austin.

Black holes have formed throughout the history of the Universe. That’s why the idea of primordial black holes isn’t too much of a surprise, although they remain elusive. In their very primitive state, they’d be ultradense objects with the mass of an asteroid punched down into something the size of an atom. They probably didn’t last very long—maybe another quintillionth of a second. After formation, they either blinked out of existence or got scattered across the expanding Universe.

The Link Between Primordial Black Holes and Dark Matter

So, how could these weird PHBs affect the formation of dark matter if they winked in and out of existence so quickly? That’s where Kaiser and his student’s work come in. They suggest that as the first PHBs scattered, they somehow “tugged” on space-time and changed something that could explain dark matter. That same process could have produced even smaller black holes with a curious property called “color charge.” And, there’s a dark matter connection.

“Color charge” is a property of quarks and gluons, and it ends up gluing them together. Think of it as a “super-charge”. Kaiser and Alonso-Monsalve suggest that some of the very early PHBs had this “supercharge” in the same way as the quarks and gluons had it. If that’s true, then the earliest super-color-charged PHBs would have been an entirely new state of matter. We don’t see them around anymore because they likely evaporated a fraction of a second after they spawned. But, their existence was necessary, particularly to the formation of dark matter.


Continue Reading

Frontier Adventure

The Great Red Spot Probably Formed in the Early 1800s

Jupiter GRS and Permanent Spot

Jupiter’s Great Red Spot (GRS) is one of the Solar System’s defining features. It’s a massive storm that astronomers have observed since the 1600s. However, its date of formation and longevity are up for debate. Have we been seeing the same phenomenon all this time?

The GRS is a gigantic anti-cyclonic (rotating counter-clockwise) storm that’s larger than Earth. Its wind speeds exceed 400 km/h (250 mp/h). It’s an icon that humans have been observing since at least the 1800s, possibly earlier. Its history, along with how it formed, is a mystery.

Its earliest observations may have been in 1632 when a German Abbott used his telescope to look at Jupiter. 32 years later, another observer reported seeing the GRS moving from east to west. Then, in 1665, Giovanni Cassini examined Jupiter with a telescope and noted the presence of a storm at the same latitude as the GRS. Cassini and other astronomers observed it continuously until 1713 and he named it the Permanent Spot.

Unfortunately, astronomers lost track of the spot. Nobody saw the GRS for 118 years until astronomer S. Schwabe observed a clear structure, roughly oval and at the same latitude as the GRS. Some think of that observation as the first observation of the current GRS and that the storm formed again at the same latitude. But the details fade the further back in time we look. There are also questions about the earlier storm and its relation to the current GRS.

New research in Geophysical Research Letters combined historical records with computer simulations of the GRS to try to understand this chimerical meteorological phenomenon. Its title is “The Origin of Jupiter’s Great Red Spot,” and the lead author is Agustín Sánchez-Lavega. Sánchez-Lavega is a Professor of Physics at the University of the Basque Country in Bilbao, Spain. He’s also head of the Planetary Sciences Group and the Department of Applied Physics at the University.

“Jupiter’s Great Red Spot (GRS) is the largest and longest-lived known vortex of all solar system planets, but its lifetime is debated, and its formation mechanism remains hidden,” the authors write in their paper.

The researchers started with historical sources dating back to the mid-1600s, just after the telescope was invented. They analyzed the size, structure, and movement of both the PS and the GRS. But that’s not a simple task. “The appearance of the GRS and its Hollow throughout the history of Jupiter observations has been highly variable due to changes in size, albedo and contrast with surrounding clouds,” they write.

Jupiter GRS and Permanent Spot 1
This figure from the research compares the Permanent Spot (PS) and the current GRS. a, b, and c are drawings by Cassini from 1677, 1690, and 1691, respectively. d is a current 2023 image of the GRS. Image Credit: Sánchez-Lavega et al. 2024.

“From the measurements of sizes and movements we deduced that it is highly unlikely that the current GRS was the PS observed by G. D. Cassini. The PS probably disappeared sometime between the mid-18th and 19th centuries, in which case we can say that the longevity of the Red Spot now exceeds 190 years at least,” said lead author Sánchez-Lavega. The GRS was 39,000 km long in 1879 and has shrunk to 14,000 km since then. It’s also become more rounded.

Four views of Jupiter and its GRS. a is a drawing of the Permanent Spot by G. D. Cassini from 19 January 1672. b is a drawing by S. Swabe from 10 May 1851. It shows the GRS area as a clear oval with limits marked by its Hollow (drawn by a red dashed line). c is a Photograph by A. A. Common from 1879. d is a photograph from Observatory Lick with a yellow filter on 14 October 1890. Each image is an astronomical image of Jupiter with south up and east down. Image Credit: Sánchez-Lavega et al. 2024.Did you miss our previous article…

Continue Reading