Mars, MOXIE and More

NASA/JPL-Caltech's photo: '...the gold-plated Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) Instrument shines after being installed inside the Perseverance rover. (from 'MOXIE Sets Consecutive Personal Bests and Mars Records for Oxygen Production'; Forrest Meyen, MOXIE Science Team Member at Lunar Outpost; MARS PERSEVERANCE ROVER Blog (December 22, 2022))
MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) in the Perseverance rover before launch.

Humanity is one step closer to exploring Mars, in person. With people living and working on the surface. And eventually, I think, living there permanently.

That’s going to take time. But like I said, we’re one step closer.

This week I’ll be talking about In Situ Resource Utilization (ISRU), the NASA-ESA Sample Return Mission, and why we’re keeping our spaceships clean. Until they land, at any rate.

Living off the Land: Old Idea, New Applications

ESA/DLR/FU-Berlin's photo, via NASA: Jezero Crater's delta, image from ESA Mars Express Orbiter. (September 21, 2020)
Jezero Crater delta, Mars.

MOXIE Sets Consecutive Personal Bests and Mars Records for Oxygen Production
Forrest Meyen, MOXIE Science Team Member at Lunar Outpost, Mars 2020 Mission Blog (December 22, 2022)

“Perseverance has a unique device near its heart that inhales Mars’ atmosphere and exhales pure oxygen. This device is named MOXIE, the Mars Oxygen In Situ Resource Utilization Experiment. The toaster-sized MOXIE uses a high-temperature, electrochemical process called solid oxide electrolysis to strip oxygen ions from the carbon dioxide in the atmosphere of Mars. There are two little gas exit ports on MOXIE: one where oxygen flows out and another where a mixture of carbon monoxide and unreacted carbon dioxide exit.

“MOXIE is significant as the first demonstration on another planet of In Situ Resource Utilization (ISRU), a group of technologies that enable extraterrestrial ‘living off the land.’…”

SIO, NOAA, US Navy, NGA, GEBCO, image Landsat (04/09/2013) Rick Potts, Susan Antón, Leslie Aiello's image: oldest known spread of genus Homo, 1,900,000 to 1,700,000 years ago. (2013) via Smithsonian Magazine“Living off the land” while we see what’s over the horizon isn’t a new idea.

It’s what we’ve been doing for the last two million years: meeting folks whose ancestors got started before ours; and that’s another topic.

Or maybe not so much.

My father grew up in a pre-industrial pocket of North America, and remembers his family literally field-testing a kerosene lamp. I remember when space ships, robots and computers were “science fiction”.

Having been raised by someone from another era, and experiencing so much change, may help me see current events as a continuation of humanity’s long story.

Take folks my culture calls Hawaiians, for example.

When folks from the Society and Marquesas islands — again, our names — sailed to islands in the North Pacific, they took along animals and plants they’d need in their new home.

And met Menehune, folks who’d settled the islands before they did.

I gather that Menehune are “mythical”.1

Maybe so, but I suspect that my culture is still getting used to the idea that “natives” may know more about their history than our professors. And no, I emphatically do not think we’ll meet Martians, or humans who got there before we did.

Getting back to current plans for exploring Mars —

What’s changed, now that we’re getting ready for extended visits to other worlds, is how much we’ll need to pick up locally.

Martian Air and Oxygen

NASA/JPL-Caltech's photo: Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE). Lowering MOXIE into the Perseverance rover. (March 21, 2019)
Lowering MOXIE into the Perseverance rover before launch at the Jet Propulsion Laboratory. (2019)

On Earth, for example, we don’t need to bring our own oxygen. Apart from 14 peaks in the Himalaya and Karakoram mountain ranges.

Mars is another matter. Even if there were as much oxygen in the Martian atmosphere as there is in Earth’s, the oxygen pressure would be far too low for us.

Actually, the Martian atmosphere has lots of oxygen, but it’s chemically bound to carbon: as carbon dioxide.2

That’s where MOXI comes in.

How MOXIE Works

NASA's illustration: 'The Perserverance rover (previously called Mars 2020) is host to seven payloads, including MOXIE, which will validate the capability to harvest volatiles from the Martian atmosphere.' (2014)
Some of what’s inside the Perserverance rover.

MOXIE is the Mars Oxygen In-Situ Resource Utilization Experiment.

It’s very roughly the size of a car battery or toaster, 9.4 by 9.4 by 12.2 inches. Make that a 12-volt SLI (Starter, Lighting and Ignition) lead-acid battery like the one in my household’s van.

Anyway, MOXIE weighs around 33 pounds and has produced more than 10 grams of oxygen per hour.

“…The atmosphere around Jezero Crater, the present location of Perseverance, reached peak density for the year mid (Earth) summer. This presented the perfect opportunity for the MOXIE science team to step on the accelerator and test how fast we could safely produce oxygen. This test occurred on Sol 534 (Aug. 22, 2022) and produced a peak of 10.44 grams per hour of oxygen. This represented a new record for Martian oxygen production! The team was thrilled to surpass our design goal of 6 grams per hour by over 4.4 grams. The peak rate was held for 1 minute of the 70 minutes oxygen was produced during the run.

“MOXIE’s next opportunity to operate came recently. Despite the decreasing density of the Mars atmosphere, on Sol 630 (Nov. 28, 2022) MOXIE managed to break the record again and produce nearly 10.56 grams per hour at peak. Oxygen production was sustained for a 9.79 grams per hour for nearly 40 minutes….”
(Forrest Meyen, MOXIE Science Team Member at Lunar Outpost, Mars 2020 Mission Blog (December 22, 2022))

MOXIE’s 10 grams of oxygen per hour is nowhere near enough for astronauts on Mars. But that’s not MOXIE’s mission.

MOXIE, like the Mars 2020 mission’s helicopter, is a technical demonstration. It’s there to see if what we figure should work, actually will work on Mars.

Here’s how MOXIE works.

First, in technojargon.

Electrical energy passes through a solid oxide electrolyzer cell (SOEC), separating carbon dioxide into oxygen and carbon monoxide. The SOEC has a nonporous solid electrolyte between two porous electrodes.

Thermal dissociation and electrocatalysis liberates an oxygen atom from carbon dioxide. This process process involves oxygen ion valencies in the electrolyte’s crystal lattice transport oxygen ions to an electrolyte-anode interface.

But never mind electrolyte-anode interfaces. There won’t, happily, be a test on this.

Basically, MOXIE’s SOEC heats Martian air, breaking carbon dioxide into oxygen, carbon monoxide and carbon, with some carbon dioxide left over.3

Oxygen Isn’t Just For Us

'A Comparison of Previously Published Papers on the Economics of Lunar
In Situ Resource Utilization (ISRU)'; Robert Shishko, Ph.D.; Jet Propulsion Laboratory, California Institute of Technology (2019) Figure 1: A Lunar ISRU Plant Concept. Associated with Synopsis of Charania and DePasquale (2007)Folks on Mars will need oxygen for the same reason we need it here. But that’s not the only — or even the main — reason for designing oxygen-makers like MOXIE.

“…Many people initially assume that this means that MOXIE’s primary purpose is to produce oxygen for future astronauts to breathe. While this is certainly an application, the most significant use of MOXIE’s technological descendants will be to produce oxygen for use as an oxidizer in rockets created to return explorers back to Earth after a successful Mars mission….”
(Forrest Meyen, MOXIE Science Team Member at Lunar Outpost, Mars 2020 Mission Blog (December 22, 2022))

An oxidizer’s not much use without something to oxidize, so we’ll be developing other ISRU tech that produces methane on Mars.

Mars isn’t the only place where we’ll be getting supplies.

Lunar soil has the raw materials — silicon, aluminum, and glass — for making solar cells. Maybe not glass, exactly, but slica we can use to make glass.

Back in the late 1950s, S. T. Demetriades outlined how we could extract oxygen and other gasses from the outer atmosphere of Earth and the Solar System’s gas giants. I gather he’s better-known for his work in magnetohydrodynamics, and that’s yet another topic.4

The last I heard, the Propulsive Fluid Accumulator (PROFAC) Demetriades described is still more theory than hardware. But that sort of tech, and the orbiting fuel stations it would supply, sounds like a good idea.

Rock Samples From Mars and the Search for Life

NASA/JPL-Caltech/Perseverance: annotated image, showing the mission's first sample depot location: where the Mars rover will deposit a group of sample tubes for possible future return to Earth. The depot location is 'Three Forks' in Jezero Crater. (August 29, 2022)
Image from Perseverance: sample tube depot location, “Three Forks”, Jezero Crater. (August 29, 2022)

NASA and ESA Agree on Next Steps to Return Mars Samples to Earth
Dewayne Washington, Karen Fox, Erin Morton (NASA); D. C. Agle (Jet Propulsion Laboratory, Pasadena, California) (October 28, 2022)

“The agency’s Perseverance rover will establish the first sample depot on Mars.

“The next step in the unprecedented campaign to return scientifically selected samples from Mars was made on Oct. 19 with a formal agreement between NASA and its partner ESA (European Space Agency). The two agencies will proceed with the creation of a sample tube depot on Mars. The sample depot, or cache, will be at ‘Three Forks,’ an area located near the base of an ancient river delta in Jezero Crater….”

“…The next step in the unprecedented campaign…”??

I’m not a great fan of how word “unprecedented” has been used lately.

A Precedented and Perfunctory Protestation

Someone's illustration of the 'Revelation 12 sign:' an imaginative mix of astrology, astronomy and folklore; with a dash of Bible-based beliefs for flavor.Happily, reporters and editors seem to realize that America’s perennial End Times Bible Prophecy reboot is anything but news.

Natural disasters are another matter.

Take this headline from a couple years back, for example:

If that sounds familiar, maybe you remember when I talked about “Colorado Families … Unprecedented Thanksgiving”, November 25, 2020.

Briefly, this time: all or nearly all folks living in 2020’s Colorado weren’t there during the 1918 pandemic. But Colorado wasn’t uninhabited back then. Not even after Charlie Phye, Jessie May Hines-Phye and their six children died.

  • 1918: When the flu came to CSU
    Kate Jeracki; with additional research by Mark Luebker, Office of the President, Vicky Lopez-Terrill, Cory Rubertus, University Archives and Special Collections; College News, Colorado State University (March 23, 2020)
  • Gunnison Colorado
    Influenza Encyclopedia, University of Michigan Library
  • The Phye Family
    Judy Walker, Dr. Adrienne LeBailly; The Pandemic Influenza Storybook

Bringing Back Rocks From Mars

NASA illustration: Mars 2020 caching strategy.)Now, about Perseverance, NASA, ESA (European Space Agency) and their “unprecedented” plans for bringing back rock samples from Mars.

In this case, we’re not looking at the usual journalistic puffery, exaggeration and outright misdirection.

Although a European Space Agency’s existence is remarkable.

I suspect that noticing what happened during the 20th century’s double-header global war encouraged Europe’s survivors to wonder if cooperation might make sense.

Wrenching myself back on-topic, what’s “unprecedented” in efforts to return samples from Mars isn’t the international cooperation angle.

And it’s not bringing back extraterrestrial samples.

Apollo 11 did that in 1969. So did the robotic Luna 16 probe in 1970. The Mir space station collected samples from low Earth orbit in 1996 through 1997.

Although it crashed in the Utah desert, the Genesis spacecraft returned samples from beyond our moon’s orbit in 2004.

The Soviet Fobos-Grunt mission would have returned samples from the Martian moon Phobos, but it crashed into the southern Pacific Ocean after a few orbits of Earth.

And we’ve already collected some material from Mars, right here on Earth. Scientists have learned quite a bit by studying Martian meteorites that fell on our planet.

But this is the first time we’ve tried getting samples back from the Martian surface: from “another planet”, as the NASA press release said.

That is a “first.” Provided that we view Earth’s moon as a satellite, rather than seeing the Earth-Moon system as a double planet.5

Sealed Samples, Sanitary Spacecraft

NASA/JPL-Caltech photo: Sample tube number 266, used to collect the first sample of Martian rock by NASA's Perseverance rover. The laser-etched serial number helps science team identify the tubes and their contents. Photo probably taken at Jet Propulsion LaboratoryI’m glad that scientists have been careful about not letting Terrestrial microbes hitch rides of our robotic probes. I also think taking reasonable precautions about material we’re bringing back makes sense.

The key word there is “reasonable”.

I enjoyed the 1971 “Andromeda Strain” film, partly because the super-secret laboratory’s fail-safe device — a nuclear bomb — would, ironically, have given the space bugs the one thing they lacked: energy. The crystalline micro-critters were almost starving, down here at the bottom of Earth’s atmosphere.

And that’s yet again another topic, almost.

Since one of our many questions about Mars and other worlds is whether or not they support or supported life, not letting our microbes loose on them is a good idea.6

Traces of Life

NASA's photo: 'The planetary landing spacecraft Viking I under assembly at Martin Marietta Aerospace. Learning about instrument sensitivity during the Ranger missions led to the use of white tech suits during assembly, which is a standard practice today.'If, say, someone had sneezed on one of the Viking landers — actually, if the person had been experiencing the common cold, we might be okay. The 200 or so microscopic pests that cause colds are all viruses.

If a few, say, rhinoviruses dropped onto the martian surface, they’d stay inert until a host came along; or, more likely, until radiation broke them up. Viruses don’t do much unless they’re inside a living cell.

Now, if a rhinoscleroma bacterium or two made the trip: they’d probably die. But I’m not entirely sure about that. Terrestrial life has been adapting to ‘unsurvivable’ conditions for a very long time.

Either way, though, there’d be at least pieces of living things — or, in the case of viruses, not-exactly-living things — on Mars. And those pieces might get blown around to other places.

Unless Martian life was very different from our version, we might never know if chemical traces of life we eventually found there were home-grown, or originally from Earth.

So I see good reason for keeping our robot spacecraft free of both living microorganisms and chemical traces of microorganisms. Make that as free as possible.

And being careful about returning samples. If for no other reason than to keep eager-to-eat terrestrial microcritters away from high-value research material.

And I’ll grant that some non-terrestrial organisms might survive, once they got here. Maybe even long enough to make trouble. So being cautious about returning samples does make sense.7

Sample Return Mission’s Current Plans

This one minute, 47 second video almost certainly doesn’t show exactly how the NASA-ESA Mars Sample Return mission will try bringing back samples from Mars.

But it’s a pretty good illustration of what’s being planned, as of July 2022.

If all goes well, a rover and/or robotic helicopters will fetch sample tubes from the cache(s) Perseverance is stocking, loading them on the Mars Ascent Vehicle (MAV).

The MAV is a small rocket that will have been brought in on the Sample Retrieval Lander: a lander/launch platform.

Well, comparatively small. The current MAV design is a foot and a half in diameter and 10 feet tall.

NASA-ESA Mars Sample Return mission plans have changed, a lot, since 2001. I strongly suspect they’ll change again before the mission’s robots leave Earth. Which, again if all goes well, will be in 2028.

But right now it looks like the Sample Retrieval Lander will throw the MAV a few meters above the lander, giving the MAV’s front a little extra push. Then, with it’s nose pointed above the horizon, the MAV’s first stage will ignite.8

This is not, putting it mildly, a simple process.

Photo from From BAS, via BBC News: 'In good shape: Halley station is now being readied for the summer season'. Jonathan Amos, BBC News (November 10, 2017)I’ve got more to say about getting samples back from Mars. And a great deal more to say about what we’ll likely do after that.

Along with what we’ve done so far, in less-unsurvivable environments.

But that will wait for another time.

Meanwhile, here’s more of what I’ve written:

1 Periods, perceptions and perspective:

2 Air and oxygen:

3 MOXIE, ISRU and car batteries:

4 Mars, materials, means and magnetohydrodynamics:

5 Rocks and rockets:

6 Rock samples and reasonable caution:

7 Studying life on Earth, and maybe elsewhere:

8 Bringing back rocks from Mars:

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A Doomed World, Spiraling to Destruction

NASA's illustration: Kepler-1658 b, a previously-discovered hot Jupiter which recent data and analysis says may be spiraling into its host star. (December 19, 2022)
Artist’s impression: Kepler-1658 b, a “hot Jupiter” in a decaying orbit. (December 19, 2022)

Kepler-1658 b, KOI-4.01, is a “hot Jupiter”. In another 2,500,000 years, give or take a bit, it won’t be there any more.

That makes it a hot subject for scientists: literally and figuratively.

Kepler-1658 b is also the the Kepler space telescope’s first confirmed exoplanet.

Frederik de Wit's 'Planisphaerium coeleste' star chart. (1670) Frederik de Wit, via Wikimedia Commons, used w/o permission.As usual, the star KOI-4 (the fourth star observed by the Kepler space telescope) had a whole mess of other designations: 2MASS J19372557+3856505, KIC 3861595, TYC 3135-652-1 and WISE J193725.57+385650.4.

But never mind that. I’ve talked about star names and designations before:

Besides, today I’ll be talking about Kepler-1658 b and why studying it matters.

To scientists, at any rate.

Kepler-1658 b, Designations and “Dunkelheim”, a Dark World

Jim Cornmell's sky chart of Caldwell Objects (September 3, 2006)) via Wikipedia, used w/o permission.Kepler-1658 b, KOI-4.01, was the first exoplanet discovered by the Kepler space telescope team.

Then how come it’s not Kepler-1 b, or KOI-1.01?

And, more to the point, why are scientists so interested in this distant world?

Kepler-1658 b’s designations are easier to explain, so I’ll start with that.

KOI stands for Kepler Object of Interest. It’s a list of 150,000 stars observed by the Kepler space telescope.

The KOI list is a subset of the KIC, Kepler Input Catalog’s 13,200,000 stars, give or take.

With nearly two dozen major current star catalogs, why make another one?

For one thing, no existing catalog — from the AC to ZC catalogues — had the breadth and depth of information needed for the Kepler space telescope. And that’s another topic.

We knew about KOI-1.01, KOI-2.01 and KOI-3.01 before Kepler began observing.

KOI-1.01, AKA TrES-2b, TrES-2, and Kepler-1b, for example: the darkest known exoplanet. It’s another hot Jupiter, discovered and confirmed in 2006. TrES-2b.

KOI-101 et cetera hasn’t been given an official name to go with its alphabet soup designations, so I’ll dub in Dunkelheim: dark home. Not that I think it’s anyone’s home.

Dunkelheim is yet another hot Jupiter; a little wider and more massive than the Solar System’s Jupiter, and hot: 1,885 Kelvin, give or take. That’s around 1,611 Celsius. It’s also the darkest known planet, darker than coal, reflecting less than 1% of its sun’s light.1

Why Kepler-1658 b isn’t Kepler-1 b

Kepler space telescope's viewing area. Each rectangle rectangles shows where one of Kepler's 95-megapixel charge-coupled device, or CCD cameras is pointed. Scientists selected these areas to avoid the region's brightest stars (the largest black dots).KOI-4 was the first star in the KOI list that hadn’t been previously confirmed as having an exoplanet. So when the Kepler team published a list of possible exoplanets, that made it the first exoplanet candidate discovered by Kepler.

When scientists find evidence that there’s a planet orbiting another star, that’s an exoplanet candidate. If more analysis shows that there exoplanet candidate really is a planet, it’s a confirmed exoplanet. If not, it stays a candidate exoplanet.

KOI-4.01 was an exoplanet candidate in 2009 because Kepler had detected a slight periodic dimming of the star.

Then scientists noticed a second dimming of KOI-4. The second dimming happened when the candidate exoplanet would have gone behind the star relative to Earth.

Since the Kepler team figured KOI-4 was about 1.1 times as wide as our sun, the dips in the star’s brightness would make KOI-4.01 about as wide as Neptune. Which wouldn’t be big enough to account for secondary dip.

And so KOI-4.01 got reclassified as a false alarm.

Provisionally. Conditionally. Until more analysis and data said otherwise. The Kepler-1658 b story is, putting it mildly, complicated.

“…The initial classification in the Kepler Input Catalog (KIC, Brown et al. 2011) for KOI 4 implied a 1.1 solar radius (R ) main-sequence star with an effective temperature (Teff ) of 6240 K (Brown et al. 2011). Based on a primary transit depth of 0.13%, this stellar classification implied that KOI 4 is orbited by a Neptune-sized planet. However, because a deep secondary eclipse was observed, KOI 4.01 was marked as a false positive (FP) in early Kepler KOI catalogs, since a secondary eclipse would not be observable for a Neptune-sized planet orbiting a main sequence star.
“The NASA Exoplanet Archive reveals a more detailed picture of the complex vetting history of Kepler’s first exoplanet candidate. KOI 4.01 was not listed in the first KOI catalog (Borucki et al. 2011a) but appeared as a ‘moderate probability candidate’ in the second KOI catalog (Borucki et al. 2011b), with the host star noted as a rapid rotator (v sin i = 40 km s−1). In the third catalog, Batalha et al. (2013) listed KOI 4.01 as a PC but it was marked back to a FP in the fourth catalog (Burke et al. 2014), likely due to the secondary eclipse….”
(“The Curious Case of KOI 4: Confirming Kepler’s First Exoplanet“, Ashley Chontos et al., The Astronomical Journal (Submitted March 4, 2019))

At any rate, by 2019 scientists had realized that KOI-4 was 2.89 times as wide as our sun. Give or take 0.12.

Ashley Chontos and others took another look at the data, showed that KOI-4.01 is bit wider than Jupiter, and published more than a dozen pages of text, charts, tables and equations explaining why Kepler 1658 b is worth even more study.2

Planetary Systems: the Solar System and Many More

Natalie Batalha's and Wendy Stenzel's chart of exoplanet populations found with Kepler data. (2017) (NASA and Ames Research Center)
Exoplanets, charted by radius and orbital period. From Kepler data.(2017)

When we started looking for planets circling other stars, we figured we’d find planetary systems like our own: small, rocky planets close to the star; gas giants farther out.

If we found any at all. The nebular hypothesis said that most stars should have planets. But it wasn’t the only explanation for how the Solar System began.

Some said that the Solar System began when another star either passed very close to, or hit, ours.

Distances between stars being what they are, that made the formation of a planetary system wildly improbable.

Immanuel Kant, Pierre Laplace or someone else developed the first nebular hypotheses for how our sun got planets. Basically, the idea is that stars and planets start out as clouds of gas and dust. A cloud’s gravity pulls it into an increasingly dense mass.

The collapsing cloud starts spinning — make that spinning faster. Its the angular momentum thing, like a figure skater spinning faster by pulling in his or her arms.

The faster-spinning cloud keeps collapsing. Eventually it’s a disk of gas and dust with a new star in the middle. Then physics happens in the disk, forming planets.3

By 1990, scientists had several reasonable explanations for why the disk would settle into rocky planets near the star and gas giants farther away.

Then we started finding other planetary systems.

Assorted “Firsts”: and Bellerophon, an Exoplanet That Shouldn’t Exist

Artist's impression of extrasolar planets in the pulsar, PSR B1257+12. (2006) From NASA/JPL-Caltech/R. Hurt (SSC), via Wikimedia Commons, used w/o permission.The first confirmed exoplanets, PSR B1257+12 B and PSR B1257+12 C, were close to their star: but their star was a pulsar, which raised a whole mess of questions.

The other first exoplanet discovered, Gamma Cephei Ab — we do have an official name for this one, Tadmor — is more over nine times as massive as Jupiter.

Tadmor’s year is a tad more than 900 days long. Which is not why it’s called Tadmor.

Tadmor’s discovery was in 1988, when some Canadian scientists said they’d found evidence that Gamma Cephei A had a planet. Then in 2002, other scientists confirmed that Gamma Cephei Ab was a planet, not something else

PSR B1257+12 B and PSR B1257+12 C, were the first confirmed exoplanets.

They were also the first known super-Earths. Super-Earths are (almost certainly rocky) planets more massive than Earth but less massive than Saturn, Uranus or Neptune.

There’s nothing like super-Earths in the Solar System, and we had more surprises coming.

The first planet found orbiting a main-sequence star was 51 Pegasi b, confirmed in 1995.

The planet’s official name is Dimidium, some folks call it Bellerophon, and I am not diving down that rabbit hole.

Dimidium/Bellerophon’s star, 51 Pegasi, is a little more massive, wider, and brighter than ours: but not by much.

Bellerophon, on the other hand, isn’t like anything in our Solar System.

It’s roughly half Jupiter’s mass — that’s not the odd part — but it whips around its star about every four and a quarter days. That’s because it’s only 0.0527 astronomical units away from 51 Pegasi.

By comparison, Mercury’s orbiting our star at about 0.387 astronomical units.

If then-current explanations of how planets form were right, Bellerophon shouldn’t have been there. But it was.

Then we started finding a whole lot more hot Jupiters.4

Finding Strange New Worlds

NASA/JPL-Caltech's illustration: TRAPPIST-1 and Solar planetary systems (February 22, 2017)
Illustration: TRAPPIST-1 and Solar planetary systems, TRAPPIST-1 system enlarged 25x. (2017)

Hot Jupiters, gas giants orbiting close to their stars, aren’t uncommon. But they’re not as common as it looked a couple decades back.

Early methods for detecting planets were good at spotting massive planets orbiting very close to their stars. Small wonder we found so many, early on.

Also small wonder we haven’t found a planetary system that’s pretty much like ours. Not yet, at any rate. New methods and data accumulating since the early 1990s has been letting scientists detect less massive planets in larger orbits.

But we’d still be hard-pressed to detect a planetary system like ours, apart maybe around our closest neighbors.

That said, we have found a vaguely-familiar-looking planetary system.

And we’ve been learning a very great deal about planets and planetary systems.5

55 Cancri A’s Planetary System: (Not) Just Like Ours

NASA/JPL-Caltech's artist's concept: two planetary systems - 55 Cancri's (top) and the Solar System. Blue lines show the orbits of planets, including the dwarf planet Pluto in our Solar System. The 55 Cancri system is currently the closest known analogue to our solar system, but it's not all that close. image credit: NASA/JPL-Caltech (2007)
Two planetary systems: 55 Cancri’s and the Solar System. NASA/JPL-Caltech. (2007)

55 Cancri is a binary star. One star, 55 Cancri A, is a K-type star on the main-sequence (probably), smaller and cooler than ours. 55 Cancri B is a red dwarf.

55 Cancri A’s five known planets are in roughly-circular orbits. The most distant one, Lipperhey, is a gas giant and about as far from 55 Cancri A as Jupiter is from our sun.

So far, the 55 Cancri A planetary system sounds a lot like the Solar System.

I figure that’s why 55 Cancri A’s planets — b, c, d, e and f — have names: Galileo, Brahe, Lipperhey, Janssen and Harriot.

But the rest, from Janssen, the nearest its star, to Harriot, in 55 Cancri A’s habitable zone, aren’t quite like anything in our Solar System.

Here’s a quick list and description, in increasing distance from 55 Cancri A:

  • e (Janssen) first super-Earth discovered around a main-sequence star
  • b (Galileo) a hot Jupiter
  • c (Brahe) probably a gas giant, mass similar to Saturn, about 0.24 AU from its star
  • f (Harriot) probably a gas giant, orbiting in 55 Cancri A’s habitable zone
  • d (Lipperhey) a gas giant, orbiting 55 Cancri A at 5.77 AU

Then there’s TOI-2180 b, a gas giant that’s a little closer to its star than Earth is to ours. Depending on which catalog you’re looking at, it orbits TOI-2180 or HD 238894.

Both designations are for the same star. It’s slightly more massive, a little hotter and a whole lot older that our sun.6

And that brings me to why Kepler-1658 b rates so much attention. Almost. First, I’ll talk about why Kepler-1658 b’s star was on the main sequence, and isn’t now.

Life Cycles of Stars

cmglee, NASA Goddard Space Flight Center's illustration: 'Stellar evolution of low-mass (left cycle) and high-mass (right cycle) stars, with examples in italics.' (2014) via Wikimedia Commons, used w/o permission.
Stellar evolution of low-mass and high-mass stars. (2014)

NASA's 'Stellar Evolution' infographic. (Posted July 9, 2012, image created October 13, 2009)Backing up a little, stars begin as collapsing clouds of gas and dust.

After a while, the lump in the middle of the cloud — a protostar, surrounded by a protoplanetary disk in Geek-speak — gets smaller and denser, it gets hotter. For the same reason a bike pump gets hotter after you’ve filled your tires.

When the protostar gets dense and hot enough, its hydrogen starts fusing into helium and the star lights up. What happens after that depends mainly on how massive the star is.7

Mass and the Main Sequence

Unknown author's (probably Prialnik, Dina; 'An Introduction to the Theory of Stellar Structure and Evolution', Cambridge University Press (2000)) Hertzsprung-Russell diagram, showing the evolutionary tracks of stars with different starting masses. Each track starts where the star has evolved to the main sequence and stops when fusion stops (for massive stars) and at the end of the red-giant branch (for stars 1 Solar mass and less). A yellow track is shown for the Sun, which will become a red giant after its main-sequence phase ends before expanding further along the asymptotic giant branch, which will be the last phase in which the Sun undergoes fusion.At this point, I could start rambling on about proton-proton chains and CNO cycles, blue giants and brown dwarfs; and then meander past the asymptotic giant, red giant and subgiant branches.8 But I won’t.

Although I’d better say a little about the subgiant branch.

How long a star stays on the main sequence depends on how much mass it starts with. Basically, the heavier a star is, the less time it spends on the main sequence.

When stars with between six tenths and ten Solar masses — mid-sized stars — start running out of hydrogen, they get bigger and brighter and move onto the subgiant branch.

Kepler 1658 b’s star — yes! I am finally back to Kepler 1658 b — is about 1.45 times our sun’s mass, and nearly three times as wide. It’s a spectral class F star that’s running out of fuel and has moved onto the subgiant branch.

And that’s why studying 1658 b matters.9 To scientists, anyway. Some scientists, that is, and science fans like me.

Science, Kepler-1658 b and Me

Ashley Chontos et al., 'Figure 3. Surface gravity versus effection temperature for confirmed Kepler exoplanet hosts. Gray points represent confirmed hosts, with known asteroseismic hosts in black. Kepler-1658, represented by the red star, sits in an underpopulated area of stellar parameter space as a massive, evolved subgiant.' (2019)Kepler 1658 b is a very special exoplanet.

It’s one of only a dozen or so whizzing around mildly-massive subgiant stars.

“…Kepler-1658 is a subgiant with Teff = 6216 ± 78 K, R? = 2.89 ± 0.12 R , and M?= 1.45 ± 0.06 M . As a massive subgiant, Kepler-1658 is currently undergoing a rapid phase of stellar evolution, joining only 9 known exoplanet hosts with similar properties (15 including statistically validated planets)….”
(“The Curious Case of KOI 4: Confirming Kepler’s First Exoplanet“, Ashley Chontos et al., The Astronomical Journal (Submitted March 4, 2019))

That’s important for several reasons.

First, mid-sized stars on the Hertzsprung-Russell diagram’s subgiant branch are changing from main-sequence stars into red giants. The Hertzsprung-Russell diagram is a brightness-mass diagram developed in the early 20th century.

Back to mid-sized stars. They’re in the subgiant transitional stage for a only short time. Short on a cosmic scale, that is. A few million years isn’t much, compared to the 13,787,000,000 years since this universe started.10

Stars that are a bit more massive than ours, in this transitional stage, and have massive planets in tight orbits — like I said, we’ve only spotted maybe a dozen or so.

A Star’s Spin

'The Curious Case of KOI 4: Confirming Kepler’s First Exoplanet Detection,' Ashley Chontos et al. - 'Figure 4. Top: Transit-clipped Quarter 11 long-cadence light curve for Kepler-1658. Bottom: Lomb-Scargle periodogram showing a strong peak at 5.66 ± 0.31 days, which we interpret as the stellar rotation period.' (2019)Kepler-1658 b’s star may be an oddball, too.

Ashley Chontos and her team didn’t have all that much data to work with — Kepler-1658b is a bit over 2,600 light-years away.

So they used mathematical tools like the Lomb-Scargle Periodogram to make sense of what they did have.

Lomb-Scargle Periodograms let researchers detect periodicity in unevenly-sampled data sets. Its generic name is least-squares spectral analysis; and it’s also callled the Vaníček method, Gauss-Vaniček method and Lomb method. None of which matters much in everyday life.

The point is that Kepler-1658 b’s star (probably) rotates ever five and two thirds days. That’s fairly fast, certainly compered to our sun’s leisurely 25 and spare change equatorial rotation period.

My memory tells me that at least a few ‘how planetary systems form’ ideas said that planets wouldn’t happen around fast-rotating stars.

It had something to do with angular momentum. Which, the last I checked, scientists still weren’t sure about when it came to how it got distributed between a star and its planets.11

Dealing With Data, Accepting New Knowledge

B. Saxton (NRAO/AUI/NSF)/ALMA (ESO/NAOJ/NRAO)'s infrared image of Elias 2-27's protoplanetary diak. (2018)
Planetary systems under construction: dusty discs surrounding nearby young stars. (2018)

I’ll occasionally get asked ‘how can scientists know how…’ stars form, old the universe is, and so on.

The short answer is, they don’t.

Not the way I can know that a plant grows from a seed.

Most seeds grow into plants in a matter of weeks or months. I can know that a seed grows into a plant by sticking it in soil and checking its progress every day or so.

Maybe somewhere in this galaxy, or in another, there are folks who live longer than we do. And have watched clouds of gas and dust condense into stars and planets.

Or at least have records spanning millions of years, the way we have an archive going back a few thousand.

Right now, we’re stuck with observing our part of this galaxy; and comparing recent data with what’s been recorded since we started keeping track of stars and planets.

Where things like protoplanetary disks are in play, previous records don’t go back more than a few decades. It’s only recently that we’ve had telescopes and other tools that let us see that sort of detail.

The good news is that we can see a very great many stars: big, small, new, old, and almost everything in between.

We can’t observe a single molecular cloud collapse into stars and planets.12 But we can spot examples of the process in various stages of development.

Distant Stars, Pixels and Making Sense

'The Curious Case of KOI 4: Confirming Kepler’s First Exoplanet Detection,' Ashley Chontos et al. - 'Figure 6. Panel (a): Target pixel files of Kepler-1658 averaged over one full quarter. Panel (b): A difference image using frames coinciding with the maxima and minima of a phase curve calculated from the measured rotation period. The star marks the location of Kepler-1658, and the companion identified using AO imaging is marked with a cross.' (2019)Now, about Kepler-1658 b: we don’t have sharp images of that star and planet.

At 2,600-plus light-years, we’re doing well to get the data we do have.

Making the job harder, there’s another star in Earth’s sky that’s about one Kepler-pixel away from Kepler-1658.

I’m running short on time, so here’s how Ashley Chontos and all explained what they did:

“…To create the difference image, we subtracted the data around the troughs from the data around the peaks. We did this for each pixel, creating a difference image which gives an indication of the relative strength of the rotational signal over the postage stamp. We then compared the difference image to an average image from the same observing quarter (Figure 6), and found that in 11 of the 17 quarters the pixel with the brightest flux is the same as the pixel where the rotational signal is the strongest….”
(“The Curious Case of KOI 4: Confirming Kepler’s First Exoplanet“, Ashley Chontos et al., The Astronomical Journal (Submitted March 4, 2019))

Since I have free will — and that’s yet another topic — I could decide that I won’t believe Ashley Chontos and other scientists.

Depending on which flavor of crackpottyness I picked, I could insist that astronomy was a government plot to enslave us all. Or a Satanic snare, because there’s no mention of exoplanets in the Bible.

Or something else, equally imaginative and running counter to what we’ve been learning about this universe.

But that doesn’t make sense. Not to me.

Paying Attention, Pursuing Truth

Roger Sinnott, Rick Fienberg's IAU /Sky and Telescope magazine sky map: Cygnus. (June 5, 2011)Wrapping up for the week: You can’t see Kepler 1658 without a very, very good telescope.

But it’s in a familiar constellation, Cygnus; a bit south of a line between Gamma Cygni and Vega, and about a third of the way over from Gamma Cygni.

Gamma Cygni’s name, one of them, is Sadr. Like many star names, it’s from Arabic, and transliteration being what it is, also spelled Sador and Sadir in my language.

Gamma Cygni/Sadr is at the intersection of my culture’s Northern Cross, an asterism; or it’s between Cygnus the swan’s wingtips.

At least one team of scientists has been paying attention to Kepler-1658 and its hot Jupiter; learning more about stars, planets, tides and physics in the process.

“…As the first evolved system with detected inspiral, Kepler-1658 is a new benchmark for understanding tidal physics at the end of the planetary life cycle….”
(“The Possible Tidal Demise of Kepler’s First Planetary System“, Shreyas Vissapragada, Ashley Chontos, et al.; The Astronomical Journal (December 19, 2022))

One point the team made is that Kepler-1658 b is, or seems to be, brighter that expected when it’s passing behind its sun — from Earth’s viewpoint.

That’s unusual, particularly for a hot Jupiter. KOI-1.01, the hot Jupiter I dubbed “Dunkelheim”, for example, is the darkest known exoplanet.

Shreyas Vissapragada et al. suggest that Kepler-1658 b is glowing, thanks to tidal heating plus its star-hugging orbit.

That makes sense. We’ve known about tidal heating — heat coming from a planet or satellite getting flexed as it changes distance from its star or planet. And Kepler-1658 b has a slightly eccentric orbit.

And I’m sure we’ll learn a great deal more by studying Kepler-1658 b. Maybe the knowledge won’t end world hunger or let the Cubs win the World Series again.13

But I think paying attention to the world around us is a good idea. Even if it doesn’t have an immediate dollars-and-cents payoff.

Putting This Universe in Perspective

Hubble/ESA's image: NGC 4848 and other galaxies. (2020)
NGC 4848 and other galaxies. Wisdom 11:22

I don’t have to take notice of what’s around me, or keep up with some of what we’re learning about this wonder-packed universe.

But again: I think it’s a good idea. And I’m far from the first person who thought so.

Question the beauty of the earth, question the beauty of the sea, question the beauty of the air…. They all answer you, ‘Here we are, look; we’re beautiful.’…
“…So in this way they arrived at a knowledge of the god who made things, through the things which he made.”
(Sermon 241, St. Augustine of Hippo (ca. 411) [emphasis mine])

“Indeed, before you the whole universe is like a grain from a balance,
or a drop of morning dew come down upon the earth.
“But you have mercy on all, because you can do all things;
and you overlook sins for the sake of repentance.”
(Wisdom 11:2223 [emphasis mine])

My interest in the beauties and wonders surrounding us connects with my opinion that pursuing truth is a good idea. None of which interferes with my faith.

If we’re doing it right,pursuing truth and beauty will lead us to God. (Catechism of the Catholic Church, 27, 31-35, 74)

That’s because all truth points toward God. Showing an interest in God’s creation and taking God seriously makes sense. (Catechism, 27, 31-35, 41, 74, 282-289, 293-294, 1723, 2294, 2500)

I’ve talked about that before. Rather often:

1 Catalogs and strange worlds:

2 Kepler-1658 b’s story, in very brief:

3 Learning where planets come from:

4 An expanding exoplanet frontier:

5 (Not) just like home:

6 Still not just like home:

7 Current best models for how planets and stars form:

8 Some geek-speak:

9 Some of why Kepler-1658 b matters:

10 Stars, the universe and a sense of scale:

11 Aren’t you glad there won’t be a test on this?

12 Seeds, clouds and history:

13 Wrapping it up for the week; Cygnus, the Chicago Cubs, stars and physics:

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Joseph Ratzinger, Pope Benedict XVI: 1927-2022

Pope Benedict XVI, March 2009. BBC News (December 31, 2022)
Pope Benedict XVI, March 2009. (BBC News)

Pope Emeritus Benedict XVI died this morning — Saturday, December 31, 2022.

His death is international news, but I don’t have much to say at the moment.

Headlines included the all-too-predictable political spins and ‘hidden meanings.’

And, happily, I saw the following articles: one from BBC News, the other from Vatican News; both giving a pretty good overview of our former pope.

“A Great Intellectual and Scholar”

Former Pope Benedict XVI dies at 95
Emily McGarvey, BBC News (December 31, 2022)

“…Following news of the former pope’s death people began gathering in St Peter’s Square in Rome.

“Annamaria, 65, and Patrizia, 64, visiting from the northern Italian city of Bologna, said they went there immediately as soon as they heard about the death.

“‘We came here to pray. He was a great pontiff, certainly very different from Francis, he was a great intellectual and scholar. Like the rest of the Church we will always remember him,’ Annamaria told the BBC….”

Crisis, Controversy and Responsibility

Benedict XVI and the Eucharist. (December 31, 2022)
“The late Pope Emeritus Benedict XVI before the Eucharist” (Vatican News)

‘God is love’: The key to Benedict’s pontificate
Vatican News (December 31, 2022)

“…As a young man, already esteemed as a theologian, Ratzinger had followed the council sessions as the peritus of Cardinal Frings of Cologne, leaning toward the reformist wing….

“…According to the young theologian, the texts ‘should respond to the most pressing questions and should do so, as far as possible, not judging or condemning, but using maternal language.’ Ratzinger favoured the foreseen liturgical reform and the reasons for its providential inevitability. He would say that to retrieve the true nature of the liturgy, it was necessary that the ‘Latin wall be demolished.’…

“…But the future Benedict XVI was also a direct witness of the post-conciliar crisis, of the controversies in the universities and theological faculties. He witnessed the questioning of essential truths of the faith and unchecked experimentation with the liturgy. Already in 1966, just a year after the Council ended, he would say that he saw a ‘low-cost Christianity’ in the offing….

“…2006 was also the year of the ‘Regensburg affair’. In giving a discourse at the university where he had taught, the Pontiff cited a historical source, without appropriating it as his own, that ended up sparking protests in the Muslim world due to how his remarks were exploited or taken out of context in the media. From then on, the Pope multiplied signs of attention toward Muslims….

“…In January 2009, the Pope decided to revoke the excommunication of four bishops illicitly ordained by Bishop Marcel Lefebvre, among whom was Richard Williamson, who denied the existence of the gas chambers. Controversy then exploded in the Jewish world, leading the Pope to take up pen and paper and, writing to all the world’s bishops, assuming full responsibility….”

Vatican News has, understandably, been giving quite a bit of attention to Benedict XVI’s life and death:

Two Millennia and Counting

Dnalor 01's photo: Cathedra Petri, Chair of Peter or Throne of Peter; in St. Peter's Basilica, Vatican City; by Gian Lorenzo Bernini (1657-1666). (May 15, 2005) via Wikimedia Commons, released under license CC-BY-SA 3.0, used w/o permission.We’ve been blessed with good Popes lately: including Saints Pius X, John XXIII, Paul VI and John Paul II. And, as one of my daughters said, we’ve needed them.

Time for me to wrap this up.

Popes come and go. The Church continues, and has for two millennia and counting.

Every half-millennium, roughly, so far, we’ve hit rough patches. I’ve talked about that before. Among other things:

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