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00:00:00 --> 00:00:03 Anna: Hello and welcome to Astronomy Daily. I'm
00:00:03 --> 00:00:03 Anna.
00:00:03 --> 00:00:06 Avery: And I'm, um, avery. It's Thursday the 18th
00:00:06 --> 00:00:08 of June, and we have a stellar show lined up
00:00:08 --> 00:00:09 for you today.
00:00:09 --> 00:00:12 Anna: Stellar quite literally. Webb and
00:00:12 --> 00:00:15 Hubble have just reclassified an entire
00:00:15 --> 00:00:18 category of object in our own galaxy.
00:00:18 --> 00:00:20 And it turns out the Milky Way has been
00:00:20 --> 00:00:22 hiding a fossil from its own formation
00:00:23 --> 00:00:25 right under our noses for 12 and a half
00:00:26 --> 00:00:26 billion years.
00:00:27 --> 00:00:29 Avery: We've also got a planet getting absolutely
00:00:29 --> 00:00:32 roasted by its star. A, uh, nail biting space
00:00:32 --> 00:00:35 rescue about to launch. A ghostly
00:00:35 --> 00:00:37 supernova from Roman times caught in a
00:00:37 --> 00:00:40 stunning new image. China sneaking up on
00:00:40 --> 00:00:42 Earth's mysterious quasi moon and a star
00:00:42 --> 00:00:45 that apparently ate one of its own planets.
00:00:45 --> 00:00:47 Anna: Big day. Let's get into it.
00:00:47 --> 00:00:50 Avery: Our first story is one of those moments in
00:00:50 --> 00:00:52 astronomy where the textbooks need to be
00:00:52 --> 00:00:54 rewritten. And it's happening right now.
00:00:55 --> 00:00:57 Anna: For decades, a stellar system called
00:00:57 --> 00:01:00 Terzon5, sitting about 22
00:01:00 --> 00:01:01 light years away in the constellation
00:01:01 --> 00:01:04 Sagittarius, has been listed in the
00:01:04 --> 00:01:07 catalogs as a globular cluster. Just
00:01:07 --> 00:01:09 another one of those ancient, densely packed
00:01:09 --> 00:01:11 balls of stars orbiting our galaxy.
00:01:12 --> 00:01:15 Avery: Well, not anymore. Researchers using both
00:01:15 --> 00:01:17 the James Webb Space Telescope and the Hubble
00:01:17 --> 00:01:20 Space Telescope have now definitively proven
00:01:20 --> 00:01:23 that Tirzon 5 is something else entirely.
00:01:23 --> 00:01:26 Something much older, much rarer, and far
00:01:26 --> 00:01:27 more scientifically exciting.
00:01:28 --> 00:01:30 Anna: They're calling it a bulge fossil fragment,
00:01:30 --> 00:01:33 and the name says it all. This object isn't
00:01:33 --> 00:01:36 a globular cluster. It's a surviving
00:01:36 --> 00:01:39 relic, a clump of matter left over from the
00:01:39 --> 00:01:42 formation of the Milky Way itself billions
00:01:42 --> 00:01:42 of years ago.
00:01:43 --> 00:01:45 Avery: A typical globular cluster has one ancient
00:01:45 --> 00:01:48 population of stars. They all formed at
00:01:48 --> 00:01:50 roughly the same time from the same material.
00:01:51 --> 00:01:54 Simple, uniform, predictable. What Webb
00:01:54 --> 00:01:57 and Hubble found in Turzon 5 is the opposite
00:01:57 --> 00:01:57 of that.
00:01:57 --> 00:02:00 Anna: Four generations of stars. Four
00:02:00 --> 00:02:03 separate bursts of star formation spanning
00:02:03 --> 00:02:05 billions of years. The oldest population
00:02:05 --> 00:02:08 formed 12 and a half billion years ago when
00:02:08 --> 00:02:10 the Milky Way itself was still being
00:02:10 --> 00:02:13 assembled. Then a, uh, second generation at
00:02:13 --> 00:02:16 4.7 billion years, a third at
00:02:16 --> 00:02:19 3.8 billion and a four fourth most
00:02:19 --> 00:02:21 recently, just two and a half billion years.
00:02:22 --> 00:02:25 Avery: Four generations in what we thought was just
00:02:25 --> 00:02:27 a run of the mill old star cluster. That's
00:02:27 --> 00:02:28 extraordinary.
00:02:29 --> 00:02:31 Anna: Webb was the key to cracking this.
00:02:31 --> 00:02:34 Terzon5 sits in the densely packed
00:02:34 --> 00:02:36 dust choked central bulge of the Milky Way,
00:02:37 --> 00:02:40 a region so crowded and obscured that Hubble
00:02:40 --> 00:02:42 alone couldn't fully resolve what was in
00:02:42 --> 00:02:45 there. Webb's infrared vision cut
00:02:45 --> 00:02:47 straight through the dust and cataloged far,
00:02:47 --> 00:02:50 far more stars and far fainter stars than
00:02:50 --> 00:02:52 any previous observation.
00:02:52 --> 00:02:54 Avery: The research team, led by PhD student
00:02:54 --> 00:02:57 Georgia Zullo from the University of Bologna,
00:02:57 --> 00:03:00 cross referenced the new Webb data with 12
00:03:00 --> 00:03:03 years of Hubble archival observations and the
00:03:03 --> 00:03:05 picture that emerged was unambiguous. This
00:03:05 --> 00:03:08 isn't a globular cluster. It never was.
00:03:08 --> 00:03:11 Anna: The reason Terzon5 was able to keep forming
00:03:11 --> 00:03:14 stars over billions of years is its sheer
00:03:14 --> 00:03:17 mass. When supernovae exploded inside
00:03:17 --> 00:03:20 it, generating heavier ELE and blasting out
00:03:20 --> 00:03:23 gas and dust, lighter systems would have lost
00:03:23 --> 00:03:25 all that material to space. Terzon
00:03:25 --> 00:03:28 5 was massive enough to hold onto it, to
00:03:28 --> 00:03:31 recycle it into new generations of stars.
00:03:31 --> 00:03:34 Avery: It's a self enriching system. Each generation
00:03:34 --> 00:03:36 of stars left behind the building blocks for
00:03:36 --> 00:03:39 the next. The researchers describe it as a
00:03:39 --> 00:03:42 cosmic fossil record, preserving the
00:03:42 --> 00:03:44 progressive enrichment of heavier elements
00:03:44 --> 00:03:46 across billions of years of star formation.
00:03:47 --> 00:03:49 Anna: What's particularly remarkable is the
00:03:49 --> 00:03:51 implication for how the Milky Way formed
00:03:52 --> 00:03:55 billions of years ago. Objects like Terazon 5
00:03:55 --> 00:03:58 would have been far more common. Primordial
00:03:58 --> 00:04:00 clumps that eventually spread out and merged
00:04:00 --> 00:04:03 to form the galaxy's central bulge. Most
00:04:03 --> 00:04:05 of them lost their identity in that process.
00:04:06 --> 00:04:09 Terzon 5 survived intact to
00:04:09 --> 00:04:09 the present
00:04:09 --> 00:04:12 Avery: day like a lump in an otherwise well
00:04:12 --> 00:04:14 mixed cake batter, which is actually how the
00:04:14 --> 00:04:16 researchers themselves described it.
00:04:16 --> 00:04:19 Anna: There is one other known object like Tirzon
00:04:19 --> 00:04:22 5, a system called Liller 1 that
00:04:22 --> 00:04:25 was similarly reclassified a few years ago.
00:04:25 --> 00:04:28 But the team is now going to examine between
00:04:28 --> 00:04:31 40 and 50 other globular clusters
00:04:31 --> 00:04:34 in the galactic bulge to see if any of them
00:04:34 --> 00:04:36 are also bulge fossil fragments
00:04:36 --> 00:04:38 hiding in plain sight.
00:04:38 --> 00:04:41 Avery: A whole new category of object. Confirmed
00:04:42 --> 00:04:44 results were presented at the 248th American
00:04:44 --> 00:04:47 Astronomical Meeting this week and published
00:04:47 --> 00:04:50 in the journal astronomy and Astrophysics.
00:04:50 --> 00:04:53 Anna: 12 and a half billion years old and
00:04:53 --> 00:04:55 still surprising us. Not bad.
00:04:55 --> 00:04:58 Avery: Terzon5 from the same AAS meeting,
00:04:58 --> 00:05:01 another web result, and this one involves a
00:05:01 --> 00:05:03 planet enduring quite possibly the most
00:05:03 --> 00:05:06 extreme weather in the known universe.
00:05:06 --> 00:05:08 Anna: We're talking about HD
00:05:08 --> 00:05:11 80606B, a
00:05:11 --> 00:05:13 gas giant four times the mass of
00:05:13 --> 00:05:16 Jupiter and one that NASA has literally given
00:05:16 --> 00:05:19 its own poster in their exoplanet series
00:05:19 --> 00:05:21 with the tagline the Roasted
00:05:21 --> 00:05:22 Exoplanet.
00:05:23 --> 00:05:25 Avery: It earned that title. HD
00:05:25 --> 00:05:27 80606B follows an
00:05:27 --> 00:05:30 extraordinarily elongated orbit around its
00:05:30 --> 00:05:33 sun like star, one of the most eccentric
00:05:33 --> 00:05:36 orbits of any known exoplanet. For most of
00:05:36 --> 00:05:38 its 111 day year. It's cruising along
00:05:38 --> 00:05:41 at a reasonable distance, but then it swings
00:05:41 --> 00:05:44 in close, very close, in a brief
00:05:44 --> 00:05:45 violent approach.
00:05:46 --> 00:05:48 Anna: During that close approach, Webb's MRII M
00:05:49 --> 00:05:51 instrument the mid infrared instrument
00:05:52 --> 00:05:54 observed the planet's temperature skyrocket
00:05:54 --> 00:05:57 by 1100 degrees Fahrenheit.
00:05:57 --> 00:06:00 That's 600 degrees Celsius of warming
00:06:00 --> 00:06:03 in the space of just a few hours. The kind of
00:06:03 --> 00:06:05 temperature swing that makes Venus look
00:06:05 --> 00:06:06 temperate.
00:06:06 --> 00:06:09 Avery: Team leader Tiffany Kattaria from NASA's Jet
00:06:09 --> 00:06:12 Propulsion Laboratory puts it hot
00:06:12 --> 00:06:14 Jupiters are already considered some of the
00:06:14 --> 00:06:17 most extreme exoplanets we know of. But even
00:06:17 --> 00:06:19 among that population, HD
00:06:19 --> 00:06:22 80606B is in a class of
00:06:22 --> 00:06:24 its own. The eccentric orbit creates a
00:06:24 --> 00:06:26 completely different beast.
00:06:26 --> 00:06:28 Anna: What makes this study particularly
00:06:28 --> 00:06:31 significant is the chemistry. Webb isn't
00:06:31 --> 00:06:34 just measuring temperature, it's detecting
00:06:34 --> 00:06:36 specific molecules in the planet's
00:06:36 --> 00:06:39 atmosphere. The team identified signatures of
00:06:39 --> 00:06:42 methane and carbon dioxide, tracking how
00:06:42 --> 00:06:44 those chemicals appear and disappear
00:06:44 --> 00:06:47 as the planet is heated and then cools again.
00:06:48 --> 00:06:51 Avery: NASA's now retired Spitzer Space Telescope
00:06:51 --> 00:06:53 had previously made infrared observations of
00:06:53 --> 00:06:56 HD 80606 b and
00:06:56 --> 00:06:58 lay the groundwork. But what Webb is
00:06:58 --> 00:07:00 delivering is orders of magnitude more
00:07:00 --> 00:07:03 detailed. Spitzer could tell you it was hot.
00:07:03 --> 00:07:06 Webb can tell you exactly what's burning.
00:07:06 --> 00:07:09 Anna: This has implications well beyond one
00:07:09 --> 00:07:11 bizarre planet. HD
00:07:11 --> 00:07:14 80606 b serves as a
00:07:14 --> 00:07:16 kind of extreme test case, a, uh, natural
00:07:16 --> 00:07:19 laboratory for understanding how atmospheres
00:07:19 --> 00:07:22 of gas giants respond to rapid
00:07:22 --> 00:07:25 intense heating. Understanding the chemistry
00:07:25 --> 00:07:28 under those conditions helps scientists model
00:07:28 --> 00:07:30 a huge range of planetary atmospheres,
00:07:30 --> 00:07:33 from hot Jupiters to potentially more Earth
00:07:33 --> 00:07:34 like worlds.
00:07:35 --> 00:07:36 Avery: The research team says they're really just
00:07:36 --> 00:07:39 getting started deciphering what Webb has to
00:07:39 --> 00:07:41 tell them from this single dataset. A, uh,
00:07:41 --> 00:07:44 planet getting roasted every 111 days.
00:07:44 --> 00:07:46 And Webb has the front row seat
00:07:46 --> 00:07:49 Anna: now to a story we've been watching closely
00:07:49 --> 00:07:51 and one that is now coming down to the wire.
00:07:52 --> 00:07:54 The rescue mission for NASA's Neil Jarrell
00:07:54 --> 00:07:56 Swift Observatory is imminent.
00:07:57 --> 00:08:00 Avery: Swift has had a remarkable 21 year career
00:08:00 --> 00:08:02 studying gamma ray bursts, the most powerful
00:08:02 --> 00:08:05 explosions in the universe, and acting as a
00:08:05 --> 00:08:07 kind of co responder, flagging
00:08:07 --> 00:08:09 transient events and alerting other
00:08:09 --> 00:08:10 telescopes to follow up.
00:08:11 --> 00:08:14 Anna: But Swift is in trouble. Its original orbit
00:08:14 --> 00:08:17 was around 600 km altitude.
00:08:17 --> 00:08:19 After 20 years, it is decayed down to
00:08:19 --> 00:08:22 roughly 400 km. And the decay
00:08:22 --> 00:08:25 is now accelerating because of increased
00:08:25 --> 00:08:28 solar activity, which expands Earth's upper
00:08:28 --> 00:08:31 atmosphere and creates more drag. Without
00:08:31 --> 00:08:33 intervention speed, Swift will re enter
00:08:33 --> 00:08:36 Earth's atmosphere sometime in autumn of this
00:08:36 --> 00:08:36 year.
00:08:37 --> 00:08:39 Avery: NASA's answer to that was to hire a startup.
00:08:40 --> 00:08:42 Last September, the agency awarded a $30
00:08:42 --> 00:08:45 million contract to Catalyst Space
00:08:45 --> 00:08:48 Technologies in Flagstaff, Arizona, giving
00:08:48 --> 00:08:51 them less than a year to build, test,
00:08:51 --> 00:08:53 launch and fly a robotic spacecraft
00:08:54 --> 00:08:56 to boost Swift into a higher orbit.
00:08:56 --> 00:08:59 Anna: That spacecraft is called Link, and as of
00:08:59 --> 00:09:02 this week it is ready. Engineers attached
00:09:02 --> 00:09:05 Link to a Northrop Grumman Pegasus XL
00:09:05 --> 00:09:08 rocket last week at NASA's Wallops Flight
00:09:08 --> 00:09:11 Facility in Virginia. The rocket is now
00:09:11 --> 00:09:13 physically attached to the underside of
00:09:13 --> 00:09:16 Northrop Grumman's Stargazer aircraft, a
00:09:16 --> 00:09:18 modified L1011 airliner, and
00:09:18 --> 00:09:21 the whole assembly is en route to Kwajalein
00:09:21 --> 00:09:24 Atoll in the Marshall Islands. The launch
00:09:24 --> 00:09:24 site.
00:09:25 --> 00:09:27 Avery: The Pegasus XL is an air launched
00:09:27 --> 00:09:30 rocket. Instead of lifting off from a pad, it
00:09:30 --> 00:09:32 drops from the aircraft at around
00:09:32 --> 00:09:35 39ft and then fires its
00:09:35 --> 00:09:37 solid rocket motors to reach orbit. Launch
00:09:37 --> 00:09:40 is expected later this month. There's a
00:09:40 --> 00:09:42 reason this particular rocket was chosen.
00:09:43 --> 00:09:45 Swift flies at an unusual orbital
00:09:45 --> 00:09:48 inclination of about 21 degrees,
00:09:48 --> 00:09:51 specifically to avoid the South Atlantic
00:09:51 --> 00:09:53 anomaly, a region of weaker magnetic
00:09:53 --> 00:09:56 shielding. That orbit is very hard to reach
00:09:56 --> 00:09:59 from conventional launch sites. Pegasus,
00:09:59 --> 00:10:01 dropped from an aircraft over the equatorial
00:10:01 --> 00:10:03 Pacific, can get there.
00:10:03 --> 00:10:05 Anna: And here's a footnote that makes this mission
00:10:05 --> 00:10:08 even more historically significant. This
00:10:08 --> 00:10:11 will be the final flight of the Pegasus XL.
00:10:12 --> 00:10:14 The vehicle has been flying since 1990,
00:10:15 --> 00:10:18 the world's first privately developed orbital
00:10:18 --> 00:10:20 launch vehicle. The 45 missions over
00:10:20 --> 00:10:23 35 years. When Lynx separates from the
00:10:23 --> 00:10:26 Pegasus XL over Kwajalein, that will be
00:10:26 --> 00:10:29 the last time an air launched rocket carries
00:10:29 --> 00:10:32 a spacecraft to orbit anywhere on Earth.
00:10:33 --> 00:10:35 Avery: NASA held a media teleconference yesterday to
00:10:35 --> 00:10:38 preview the mission. Once Link reaches orbit,
00:10:38 --> 00:10:41 it'll spend two to three weeks closing in on
00:10:41 --> 00:10:43 Swift approaching, carefully
00:10:44 --> 00:10:46 imaging the observatory from standoff
00:10:46 --> 00:10:48 distances to assess its current state and
00:10:48 --> 00:10:50 then docking to boost it to a higher
00:10:50 --> 00:10:53 altitude. Altitude. If all goes to plan,
00:10:53 --> 00:10:56 Swift gets a new lease on life and the US
00:10:56 --> 00:10:58 demonstrates a critical orbital servicing
00:10:58 --> 00:11:01 capability that will matter enormously for
00:11:01 --> 00:11:01 future missions.
00:11:02 --> 00:11:04 Anna: A rescue mission, a final chapter for an
00:11:04 --> 00:11:07 iconic rocket, and a preview of the future
00:11:07 --> 00:11:10 of spacecraft servicing all in one launch.
00:11:10 --> 00:11:13 We will absolutely be tracking this one.
00:11:13 --> 00:11:15 Avery: Our fourth story takes us to the very heart
00:11:15 --> 00:11:18 of the Milky Way and to a cosmic
00:11:18 --> 00:11:20 explosion whose light reached Earth
00:11:20 --> 00:11:23 1700 years ago in the third century
00:11:23 --> 00:11:23 CE.
00:11:24 --> 00:11:27 Anna: A stunning new multi telescope image
00:11:27 --> 00:11:30 released today as NASA's Astronomy Picture of
00:11:30 --> 00:11:32 the day has revealed what astronomers believe
00:11:32 --> 00:11:35 is the remnant of that ancient supernova,
00:11:35 --> 00:11:38 a blue glowing blob lurking near the
00:11:38 --> 00:11:41 galactic center just waiting to be properly
00:11:41 --> 00:11:41 identified.
00:11:42 --> 00:11:44 Avery: The image is a technical marvel. It
00:11:44 --> 00:11:46 combines data from four different
00:11:47 --> 00:11:50 X ray observations from both NASA's Chandra
00:11:50 --> 00:11:53 X Ray Telescope and ESA's XMM M
00:11:53 --> 00:11:56 M Newton Space Telescope showing that blue
00:11:56 --> 00:11:59 structure radio waves from the MeerKAT
00:11:59 --> 00:12:01 telescope in South Africa, revealing a large
00:12:01 --> 00:12:04 cloud of material and optical background
00:12:04 --> 00:12:06 star data from the Pan Starrs telescopes in
00:12:06 --> 00:12:07 Hawaii.
00:12:07 --> 00:12:10 Anna: Each telescope is sensitive to a different
00:12:10 --> 00:12:12 type of radiation, and together they build a
00:12:12 --> 00:12:14 much richer picture than any single
00:12:14 --> 00:12:17 observatory could. The blue emission in X
00:12:17 --> 00:12:20 rays is particularly telling. It's the
00:12:20 --> 00:12:23 signature of extremely hot gas, the kind you
00:12:23 --> 00:12:25 get when a massive star explodes and its
00:12:25 --> 00:12:28 shock waves slam M into the surrounding
00:12:28 --> 00:12:29 interstellar medium.
00:12:29 --> 00:12:32 Avery: The galactic center is an extraordinarily
00:12:32 --> 00:12:34 challenging region to study. It's packed with
00:12:34 --> 00:12:37 stars, threaded with gas and dust clouds,
00:12:37 --> 00:12:40 and home to Sagittarius, a star,
00:12:40 --> 00:12:42 the supermassive black hole at the heart of
00:12:42 --> 00:12:45 our galaxy. Disentangling individual
00:12:45 --> 00:12:47 structures in that environment is a serious
00:12:47 --> 00:12:50 scientific challenge, which is why multi
00:12:50 --> 00:12:52 wavelength approaches like this are so
00:12:52 --> 00:12:54 Anna: valuable if confirmed as a
00:12:54 --> 00:12:57 supernova remnant. This object joins a
00:12:57 --> 00:13:00 rich catalog of such structures scattered
00:13:00 --> 00:13:03 across the galaxy. The expanding shells
00:13:03 --> 00:13:06 and shocked gas left behind by stellar
00:13:06 --> 00:13:09 explosions. Each one is a window
00:13:09 --> 00:13:11 into the life and death of massive M stars
00:13:12 --> 00:13:14 and into the cycle of material that
00:13:14 --> 00:13:17 ultimately seeded the formation of new
00:13:17 --> 00:13:20 stars, planets, and, yes, the
00:13:20 --> 00:13:22 atoms in our own bodies.
00:13:22 --> 00:13:25 Avery: A star died spectacularly
00:13:25 --> 00:13:27 17 centuries ago. We're only now
00:13:27 --> 00:13:29 beginning to fully see what it left behind.
00:13:30 --> 00:13:33 Anna: Story 5 and we're heading to a corner of
00:13:33 --> 00:13:36 the solar system very close to home. Though
00:13:36 --> 00:13:39 you've probably never heard of it, China's
00:13:39 --> 00:13:41 Tianwen 2 spacecraft is now in the
00:13:41 --> 00:13:44 vicinity of an asteroid called
00:13:44 --> 00:13:46 Kamoalewa, and its upcoming
00:13:46 --> 00:13:49 sample collection mission could resolve one
00:13:49 --> 00:13:51 of the most intriguing, intriguing mysteries
00:13:51 --> 00:13:53 in planetary science.
00:13:53 --> 00:13:56 Avery: Kamoalewa, spelled K A
00:13:56 --> 00:13:59 M M O O A
00:13:59 --> 00:14:02 L E W A, is a Hawaiian
00:14:02 --> 00:14:04 name, and with good reason. It was discovered
00:14:04 --> 00:14:07 in 2016 by the Pan Starrs Telescope on
00:14:07 --> 00:14:10 Haleakala in Hawaii, and the name was
00:14:10 --> 00:14:12 given by Hawaiian language students working
00:14:12 --> 00:14:15 with the University of Hawaii's Institute for
00:14:15 --> 00:14:17 Astronomy. It means, roughly, an
00:14:17 --> 00:14:19 oscillating celestial fragment,
00:14:20 --> 00:14:22 Anna: and oscillating is apartment
00:14:22 --> 00:14:25 Kamoalewa is what's called a
00:14:25 --> 00:14:28 quasi satellite of Earth. It orbits the
00:14:28 --> 00:14:31 sun, not Earth, but does so in an
00:14:31 --> 00:14:33 orbit so similar to ours that it
00:14:33 --> 00:14:36 perpetually loops around us in a kind of
00:14:36 --> 00:14:39 slow, gravitationally choreographed dance.
00:14:39 --> 00:14:42 It's been Earth's companion for more than a
00:14:42 --> 00:14:45 century and will remain so for several more.
00:14:46 --> 00:14:48 Avery: The asteroid itself is tiny, estimated
00:14:48 --> 00:14:51 between 40 and 100 meters across.
00:14:51 --> 00:14:54 It rotates once every 28 minutes, which is
00:14:54 --> 00:14:57 very fast, and it may be a solid chunk of
00:14:57 --> 00:14:59 rock rather than a loosely bound rubble pile.
00:15:00 --> 00:15:02 You'd expect the rubble pile to fly apart at
00:15:02 --> 00:15:03 that Spin rate.
00:15:04 --> 00:15:07 Anna: Now, here's the really fascinating part. When
00:15:07 --> 00:15:09 astronomers examined Kamoalewa's
00:15:09 --> 00:15:12 reflectance spectrum, the specific pattern of
00:15:12 --> 00:15:15 light it reflects, they found it matched
00:15:15 --> 00:15:18 weathered lunar rock. That sparked a theory
00:15:18 --> 00:15:21 this asteroid might actually be a
00:15:21 --> 00:15:23 fragment of the Moon, blasted into space
00:15:23 --> 00:15:26 by an ancient impact and subsequently
00:15:26 --> 00:15:29 captured into this unusual Earth
00:15:29 --> 00:15:30 accompanying orbit.
00:15:30 --> 00:15:33 Avery: Which is exactly why China chose it as the
00:15:33 --> 00:15:36 target for Tianwen 2, their asteroid
00:15:36 --> 00:15:38 sample return mission that launched in May
00:15:38 --> 00:15:41 2025. The spacecraft performed its main
00:15:41 --> 00:15:44 orbit insertion burn on June 7, and
00:15:44 --> 00:15:46 since then has been performing a uh, series
00:15:46 --> 00:15:49 of smaller fine adjustment burns to zero in
00:15:49 --> 00:15:52 on the asteroid. Amateur radio astronomers
00:15:52 --> 00:15:54 in Germany and the Netherlands have
00:15:54 --> 00:15:56 independently been tracking these maneuvers
00:15:56 --> 00:15:59 by receiving Tianwen 2's X band signal.
00:15:59 --> 00:16:02 Since China's space agency has released no
00:16:02 --> 00:16:04 Anna: official updates, sample collection is
00:16:04 --> 00:16:07 scheduled to begin on July 4, a date
00:16:07 --> 00:16:10 that carries its own kind of poetry. With
00:16:10 --> 00:16:13 Tianwen 2 departing Kamoalewa
00:16:13 --> 00:16:16 in April 2027 and sample
00:16:16 --> 00:16:18 capsule returning to Earth's surface in late
00:16:18 --> 00:16:21 November 2027. If those samples
00:16:21 --> 00:16:24 match lunar composition at the isotopic
00:16:24 --> 00:16:27 level, the Moon fragment theory will be
00:16:27 --> 00:16:30 confirmed, and we'll have a whole new
00:16:30 --> 00:16:32 category of object in the solar system's
00:16:32 --> 00:16:33 menagerie.
00:16:33 --> 00:16:35 Avery: There's a wrinkle, though. A paper just
00:16:35 --> 00:16:38 published in Nature Communications has
00:16:38 --> 00:16:40 challenged the lunar origin story, suggesting
00:16:40 --> 00:16:43 instead that Kamu Elewa might be an
00:16:43 --> 00:16:46 ordinary rocky asteroid from the inner
00:16:46 --> 00:16:48 asteroid belt, one that just happens to have
00:16:48 --> 00:16:50 been heavily space weathered in a way that
00:16:50 --> 00:16:53 mimics lunar material. So the debate is very
00:16:53 --> 00:16:56 much alive, and Tianwen two samples will
00:16:56 --> 00:16:57 settle it.
00:16:57 --> 00:17:00 Anna: And this mission has a second act.
00:17:00 --> 00:17:03 After delivering its samples, Tianwen 2
00:17:03 --> 00:17:06 won't be done. It'll use an Earth gravity
00:17:06 --> 00:17:08 assist to slingshot toward the main
00:17:08 --> 00:17:11 asteroid belt, eventually rendezvousing with
00:17:11 --> 00:17:14 an object called 311P
00:17:14 --> 00:17:17 PAN STARS, an active asteroid. More
00:17:17 --> 00:17:19 of a comet, really. In January
00:17:19 --> 00:17:22 2035, one spacecraft, two
00:17:22 --> 00:17:24 completely different destinations, a, uh,
00:17:24 --> 00:17:25 decade apart.
00:17:26 --> 00:17:28 Avery: Quite the itinerary. We'll keep you posted as
00:17:28 --> 00:17:30 sampling operations approach.
00:17:30 --> 00:17:33 Now for a final story for today is a
00:17:33 --> 00:17:36 cautionary tale from about 1300 light years
00:17:36 --> 00:17:38 away, and the reminder that not every
00:17:38 --> 00:17:40 planet gets to live out its natural lifespan.
00:17:41 --> 00:17:43 Anna: Meet TOI
00:17:43 --> 00:17:46 5882, a, uh, binary
00:17:46 --> 00:17:48 star system. Two stars orbiting
00:17:48 --> 00:17:51 each other, looking, by most measures, like
00:17:51 --> 00:17:54 a perfectly ordinary stellar pair.
00:17:54 --> 00:17:57 Except that astronomers have now detected
00:17:57 --> 00:18:00 a striking chemical difference between the
00:18:00 --> 00:18:03 two stars, a difference that points to one of
00:18:03 --> 00:18:06 them having consumed at least one of
00:18:06 --> 00:18:06 its planets.
00:18:07 --> 00:18:09 Avery: The study was led by Brooke Cotton of the
00:18:09 --> 00:18:11 University of Michigan, and it builds on a
00:18:11 --> 00:18:14 technique that's been growing in power over
00:18:14 --> 00:18:16 recent years. When a star ingests a
00:18:16 --> 00:18:19 planet, it swallows the planet's rocky
00:18:19 --> 00:18:22 material iron, silicon, magnesium
00:18:22 --> 00:18:24 and other elements that are rare in a star's
00:18:24 --> 00:18:27 outer layers but abundant in a rocky world.
00:18:27 --> 00:18:29 That leaves a detectable chemical
00:18:29 --> 00:18:30 fingerprint.
00:18:30 --> 00:18:32 Anna: In the case of TOI
00:18:32 --> 00:18:35 5882, that imbalance is
00:18:35 --> 00:18:38 there. One star in the pair carries the
00:18:38 --> 00:18:41 chemical signature of having swallowed rocky
00:18:41 --> 00:18:44 planetary material. The other doesn't.
00:18:44 --> 00:18:46 The researchers estimate the consumed
00:18:46 --> 00:18:49 material could amount to the equivalent of
00:18:49 --> 00:18:52 several Earth masses, meaning this wasn't
00:18:52 --> 00:18:54 just a small pebble. At least one
00:18:54 --> 00:18:57 substantial planet met its end inside that
00:18:57 --> 00:18:58 star.
00:18:58 --> 00:19:01 Avery: The mechanics of how planets end up falling
00:19:01 --> 00:19:02 into their host stars are still being
00:19:02 --> 00:19:05 actively studied. And gravitational
00:19:05 --> 00:19:06 interactions with other planets in the
00:19:06 --> 00:19:09 system, gradual orbital decay, close
00:19:09 --> 00:19:12 encounters early in the system's formation
00:19:12 --> 00:19:14 all of these can perturb a planet's orbit
00:19:14 --> 00:19:16 inward until it crosses the point of no
00:19:16 --> 00:19:19 return. What's fascinating is that the
00:19:19 --> 00:19:21 surviving star carries the record of what
00:19:21 --> 00:19:23 happened to its twin's planetary family
00:19:24 --> 00:19:25 written in its own chemistry.
00:19:26 --> 00:19:28 Anna: As our ability to analyze stellar
00:19:28 --> 00:19:31 compositions becomes ever more precise,
00:19:31 --> 00:19:34 we're finding more and more binary systems
00:19:34 --> 00:19:36 with this kind of chemical imbal, which
00:19:36 --> 00:19:39 raises a sobering question about how
00:19:39 --> 00:19:41 common planetary ingestion really is,
00:19:42 --> 00:19:45 and whether our own solar system, with
00:19:45 --> 00:19:47 Jupiter acting as a kind of gravitational
00:19:47 --> 00:19:50 shepherd for the inner planets, has been
00:19:50 --> 00:19:51 unusually well behaved.
00:19:52 --> 00:19:54 Avery: Stars they can be a bit greedy sometimes,
00:19:55 --> 00:19:56 apparently.
00:19:56 --> 00:19:59 Anna: But on that cosmic note, it's time to wrap
00:19:59 --> 00:20:00 up today's show.
00:20:00 --> 00:20:02 Avery: What an episode today. A fossil from the dawn
00:20:02 --> 00:20:05 of the Milky Way, a planet being roasted
00:20:05 --> 00:20:08 alive, a 21 year old space telescope
00:20:08 --> 00:20:10 getting a second chance at life, an ancient
00:20:10 --> 00:20:13 supernova captured across four wavelengths,
00:20:13 --> 00:20:16 a quasi moon about to give up its secrets,
00:20:16 --> 00:20:19 and a star that ate its own planet. Not a
00:20:19 --> 00:20:20 slow news day in space.
00:20:20 --> 00:20:23 Anna: Never is. If you enjoyed today's show, please
00:20:23 --> 00:20:26 do subscribe. Leave us a review and share
00:20:26 --> 00:20:28 Astronomy Daily with someone who should be
00:20:28 --> 00:20:30 looking up a little more. You'll find us
00:20:30 --> 00:20:33 ah@astronomydaily IO and on
00:20:33 --> 00:20:36 social media astrodaily pod. We'll
00:20:36 --> 00:20:38 be back tomorrow with your Friday edition.
00:20:38 --> 00:20:40 Until then, keep your eyes in the
00:20:40 --> 00:20:43 Avery: sky and your mind in the stars. Good night
00:20:43 --> 00:20:43 everyone.
00:20:56 --> 00:20:56 Anna: Stories.