A Milky Way Fossil Unearthed, Extreme Weather on a Roasted Planet, and a Space Telescope's Last Chance

Anna: Hello and welcome to Astronomy Daily. I'm

Anna.

Avery: And I'm, um, avery. It's Thursday the 18th

of June, and we have a stellar show lined up

for you today.

Anna: Stellar quite literally. Webb and

Hubble have just reclassified an entire

category of object in our own galaxy.

And it turns out the Milky Way has been

hiding a fossil from its own formation

right under our noses for 12 and a half

billion years.

Avery: We've also got a planet getting absolutely

roasted by its star. A, uh, nail biting space

rescue about to launch. A ghostly

supernova from Roman times caught in a

stunning new image. China sneaking up on

Earth's mysterious quasi moon and a star

that apparently ate one of its own planets.

Anna: Big day. Let's get into it.

Avery: Our first story is one of those moments in

astronomy where the textbooks need to be

rewritten. And it's happening right now.

Anna: For decades, a stellar system called

Terzon5, sitting about 22,000

light years away in the constellation

Sagittarius, has been listed in the

catalogs as a globular cluster. Just

another one of those ancient, densely packed

balls of stars orbiting our galaxy.

Avery: Well, not anymore. Researchers using both

the James Webb Space Telescope and the Hubble

Space Telescope have now definitively proven

that Tirzon 5 is something else entirely.

Something much older, much rarer, and far

more scientifically exciting.

Anna: They're calling it a bulge fossil fragment,

and the name says it all. This object isn't

a globular cluster. It's a surviving

relic, a clump of matter left over from the

formation of the Milky Way itself billions

of years ago.

Avery: A typical globular cluster has one ancient

population of stars. They all formed at

roughly the same time from the same material.

Simple, uniform, predictable. What Webb

and Hubble found in Turzon 5 is the opposite

of that.

Anna: Four generations of stars. Four

separate bursts of star formation spanning

billions of years. The oldest population

formed 12 and a half billion years ago when

the Milky Way itself was still being

assembled. Then a, uh, second generation at

4.7 billion years, a third at

3.8 billion and a four fourth most

recently, just two and a half billion years.

Avery: Four generations in what we thought was just

a run of the mill old star cluster. That's

extraordinary.

Anna: Webb was the key to cracking this.

Terzon5 sits in the densely packed

dust choked central bulge of the Milky Way,

a region so crowded and obscured that Hubble

alone couldn't fully resolve what was in

there. Webb's infrared vision cut

straight through the dust and cataloged far,

far more stars and far fainter stars than

any previous observation.

Avery: The research team, led by PhD student

Georgia Zullo from the University of Bologna,

cross referenced the new Webb data with 12

years of Hubble archival observations and the

picture that emerged was unambiguous. This

isn't a globular cluster. It never was.

Anna: The reason Terzon5 was able to keep forming

stars over billions of years is its sheer

mass. When supernovae exploded inside

it, generating heavier ELE and blasting out

gas and dust, lighter systems would have lost

all that material to space. Terzon

5 was massive enough to hold onto it, to

recycle it into new generations of stars.

Avery: It's a self enriching system. Each generation

of stars left behind the building blocks for

the next. The researchers describe it as a

cosmic fossil record, preserving the

progressive enrichment of heavier elements

across billions of years of star formation.

Anna: What's particularly remarkable is the

implication for how the Milky Way formed

billions of years ago. Objects like Terazon 5

would have been far more common. Primordial

clumps that eventually spread out and merged

to form the galaxy's central bulge. Most

of them lost their identity in that process.

Terzon 5 survived intact to

the present

Avery: day like a lump in an otherwise well

mixed cake batter, which is actually how the

researchers themselves described it.

Anna: There is one other known object like Tirzon

5, a system called Liller 1 that

was similarly reclassified a few years ago.

But the team is now going to examine between

40 and 50 other globular clusters

in the galactic bulge to see if any of them

are also bulge fossil fragments

hiding in plain sight.

Avery: A whole new category of object. Confirmed

results were presented at the 248th American

Astronomical Meeting this week and published

in the journal astronomy and Astrophysics.

Anna: 12 and a half billion years old and

still surprising us. Not bad.

Avery: Terzon5 from the same AAS meeting,

another web result, and this one involves a

planet enduring quite possibly the most

extreme weather in the known universe.

Anna: We're talking about HD

80606B, a

gas giant four times the mass of

Jupiter and one that NASA has literally given

its own poster in their exoplanet series

with the tagline the Roasted

Exoplanet.

Avery: It earned that title. HD

80606B follows an

extraordinarily elongated orbit around its

sun like star, one of the most eccentric

orbits of any known exoplanet. For most of

its 111 day year. It's cruising along

at a reasonable distance, but then it swings

in close, very close, in a brief

violent approach.

Anna: During that close approach, Webb's MRII M

instrument the mid infrared instrument

observed the planet's temperature skyrocket

by 1100 degrees Fahrenheit.

That's 600 degrees Celsius of warming

in the space of just a few hours. The kind of

temperature swing that makes Venus look

temperate.

Avery: Team leader Tiffany Kattaria from NASA's Jet

Propulsion Laboratory puts it hot

Jupiters are already considered some of the

most extreme exoplanets we know of. But even

among that population, HD

80606B is in a class of

its own. The eccentric orbit creates a

completely different beast.

Anna: What makes this study particularly

significant is the chemistry. Webb isn't

just measuring temperature, it's detecting

specific molecules in the planet's

atmosphere. The team identified signatures of

methane and carbon dioxide, tracking how

those chemicals appear and disappear

as the planet is heated and then cools again.

Avery: NASA's now retired Spitzer Space Telescope

had previously made infrared observations of

HD 80606 b and

lay the groundwork. But what Webb is

delivering is orders of magnitude more

detailed. Spitzer could tell you it was hot.

Webb can tell you exactly what's burning.

Anna: This has implications well beyond one

bizarre planet. HD

80606 b serves as a

kind of extreme test case, a, uh, natural

laboratory for understanding how atmospheres

of gas giants respond to rapid

intense heating. Understanding the chemistry

under those conditions helps scientists model

a huge range of planetary atmospheres,

from hot Jupiters to potentially more Earth

like worlds.

Avery: The research team says they're really just

getting started deciphering what Webb has to

tell them from this single dataset. A, uh,

planet getting roasted every 111 days.

And Webb has the front row seat

Anna: now to a story we've been watching closely

and one that is now coming down to the wire.

The rescue mission for NASA's Neil Jarrell

Swift Observatory is imminent.

Avery: Swift has had a remarkable 21 year career

studying gamma ray bursts, the most powerful

explosions in the universe, and acting as a

kind of co responder, flagging

transient events and alerting other

telescopes to follow up.

Anna: But Swift is in trouble. Its original orbit

was around 600 km altitude.

After 20 years, it is decayed down to

roughly 400 km. And the decay

is now accelerating because of increased

solar activity, which expands Earth's upper

atmosphere and creates more drag. Without

intervention speed, Swift will re enter

Earth's atmosphere sometime in autumn of this

year.

Avery: NASA's answer to that was to hire a startup.

Last September, the agency awarded a $30

million contract to Catalyst Space

Technologies in Flagstaff, Arizona, giving

them less than a year to build, test,

launch and fly a robotic spacecraft

to boost Swift into a higher orbit.

Anna: That spacecraft is called Link, and as of

this week it is ready. Engineers attached

Link to a Northrop Grumman Pegasus XL

rocket last week at NASA's Wallops Flight

Facility in Virginia. The rocket is now

physically attached to the underside of

Northrop Grumman's Stargazer aircraft, a

modified L1011 airliner, and

the whole assembly is en route to Kwajalein

Atoll in the Marshall Islands. The launch

site.

Avery: The Pegasus XL is an air launched

rocket. Instead of lifting off from a pad, it

drops from the aircraft at around

39,000ft and then fires its

solid rocket motors to reach orbit. Launch

is expected later this month. There's a

reason this particular rocket was chosen.

Swift flies at an unusual orbital

inclination of about 21 degrees,

specifically to avoid the South Atlantic

anomaly, a region of weaker magnetic

shielding. That orbit is very hard to reach

from conventional launch sites. Pegasus,

dropped from an aircraft over the equatorial

Pacific, can get there.

Anna: And here's a footnote that makes this mission

even more historically significant. This

will be the final flight of the Pegasus XL.

The vehicle has been flying since 1990,

the world's first privately developed orbital

launch vehicle. The 45 missions over

35 years. When Lynx separates from the

Pegasus XL over Kwajalein, that will be

the last time an air launched rocket carries

a spacecraft to orbit anywhere on Earth.

Avery: NASA held a media teleconference yesterday to

preview the mission. Once Link reaches orbit,

it'll spend two to three weeks closing in on

Swift approaching, carefully

imaging the observatory from standoff

distances to assess its current state and

then docking to boost it to a higher

altitude. Altitude. If all goes to plan,

Swift gets a new lease on life and the US

demonstrates a critical orbital servicing

capability that will matter enormously for

future missions.

Anna: A rescue mission, a final chapter for an

iconic rocket, and a preview of the future

of spacecraft servicing all in one launch.

We will absolutely be tracking this one.

Avery: Our fourth story takes us to the very heart

of the Milky Way and to a cosmic

explosion whose light reached Earth

1700 years ago in the third century

CE.

Anna: A stunning new multi telescope image

released today as NASA's Astronomy Picture of

the day has revealed what astronomers believe

is the remnant of that ancient supernova,

a blue glowing blob lurking near the

galactic center just waiting to be properly

identified.

Avery: The image is a technical marvel. It

combines data from four different

X ray observations from both NASA's Chandra

X Ray Telescope and ESA's XMM M

M Newton Space Telescope showing that blue

structure radio waves from the MeerKAT

telescope in South Africa, revealing a large

cloud of material and optical background

star data from the Pan Starrs telescopes in

Hawaii.

Anna: Each telescope is sensitive to a different

type of radiation, and together they build a

much richer picture than any single

observatory could. The blue emission in X

rays is particularly telling. It's the

signature of extremely hot gas, the kind you

get when a massive star explodes and its

shock waves slam M into the surrounding

interstellar medium.

Avery: The galactic center is an extraordinarily

challenging region to study. It's packed with

stars, threaded with gas and dust clouds,

and home to Sagittarius, a star,

the supermassive black hole at the heart of

our galaxy. Disentangling individual

structures in that environment is a serious

scientific challenge, which is why multi

wavelength approaches like this are so

Anna: valuable if confirmed as a

supernova remnant. This object joins a

rich catalog of such structures scattered

across the galaxy. The expanding shells

and shocked gas left behind by stellar

explosions. Each one is a window

into the life and death of massive M stars

and into the cycle of material that

ultimately seeded the formation of new

stars, planets, and, yes, the

atoms in our own bodies.

Avery: A star died spectacularly

17 centuries ago. We're only now

beginning to fully see what it left behind.

Anna: Story 5 and we're heading to a corner of

the solar system very close to home. Though

you've probably never heard of it, China's

Tianwen 2 spacecraft is now in the

vicinity of an asteroid called

Kamoalewa, and its upcoming

sample collection mission could resolve one

of the most intriguing, intriguing mysteries

in planetary science.

Avery: Kamoalewa, spelled K A

M M O O A

L E W A, is a Hawaiian

name, and with good reason. It was discovered

in 2016 by the Pan Starrs Telescope on

Haleakala in Hawaii, and the name was

given by Hawaiian language students working

with the University of Hawaii's Institute for

Astronomy. It means, roughly, an

oscillating celestial fragment,

Anna: and oscillating is apartment

Kamoalewa is what's called a

quasi satellite of Earth. It orbits the

sun, not Earth, but does so in an

orbit so similar to ours that it

perpetually loops around us in a kind of

slow, gravitationally choreographed dance.

It's been Earth's companion for more than a

century and will remain so for several more.

Avery: The asteroid itself is tiny, estimated

between 40 and 100 meters across.

It rotates once every 28 minutes, which is

very fast, and it may be a solid chunk of

rock rather than a loosely bound rubble pile.

You'd expect the rubble pile to fly apart at

that Spin rate.

Anna: Now, here's the really fascinating part. When

astronomers examined Kamoalewa's

reflectance spectrum, the specific pattern of

light it reflects, they found it matched

weathered lunar rock. That sparked a theory

this asteroid might actually be a

fragment of the Moon, blasted into space

by an ancient impact and subsequently

captured into this unusual Earth

accompanying orbit.

Avery: Which is exactly why China chose it as the

target for Tianwen 2, their asteroid

sample return mission that launched in May

2025. The spacecraft performed its main

orbit insertion burn on June 7, and

since then has been performing a uh, series

of smaller fine adjustment burns to zero in

on the asteroid. Amateur radio astronomers

in Germany and the Netherlands have

independently been tracking these maneuvers

by receiving Tianwen 2's X band signal.

Since China's space agency has released no

Anna: official updates, sample collection is

scheduled to begin on July 4, a date

that carries its own kind of poetry. With

Tianwen 2 departing Kamoalewa

in April 2027 and sample

capsule returning to Earth's surface in late

November 2027. If those samples

match lunar composition at the isotopic

level, the Moon fragment theory will be

confirmed, and we'll have a whole new

category of object in the solar system's

menagerie.

Avery: There's a wrinkle, though. A paper just

published in Nature Communications has

challenged the lunar origin story, suggesting

instead that Kamu Elewa might be an

ordinary rocky asteroid from the inner

asteroid belt, one that just happens to have

been heavily space weathered in a way that

mimics lunar material. So the debate is very

much alive, and Tianwen two samples will

settle it.

Anna: And this mission has a second act.

After delivering its samples, Tianwen 2

won't be done. It'll use an Earth gravity

assist to slingshot toward the main

asteroid belt, eventually rendezvousing with

an object called 311P

PAN STARS, an active asteroid. More

of a comet, really. In January

2035, one spacecraft, two

completely different destinations, a, uh,

decade apart.

Avery: Quite the itinerary. We'll keep you posted as

sampling operations approach.

Now for a final story for today is a

cautionary tale from about 1300 light years

away, and the reminder that not every

planet gets to live out its natural lifespan.

Anna: Meet TOI

5882, a, uh, binary

star system. Two stars orbiting

each other, looking, by most measures, like

a perfectly ordinary stellar pair.

Except that astronomers have now detected

a striking chemical difference between the

two stars, a difference that points to one of

them having consumed at least one of

its planets.

Avery: The study was led by Brooke Cotton of the

University of Michigan, and it builds on a

technique that's been growing in power over

recent years. When a star ingests a

planet, it swallows the planet's rocky

material iron, silicon, magnesium

and other elements that are rare in a star's

outer layers but abundant in a rocky world.

That leaves a detectable chemical

fingerprint.

Anna: In the case of TOI

5882, that imbalance is

there. One star in the pair carries the

chemical signature of having swallowed rocky

planetary material. The other doesn't.

The researchers estimate the consumed

material could amount to the equivalent of

several Earth masses, meaning this wasn't

just a small pebble. At least one

substantial planet met its end inside that

star.

Avery: The mechanics of how planets end up falling

into their host stars are still being

actively studied. And gravitational

interactions with other planets in the

system, gradual orbital decay, close

encounters early in the system's formation

all of these can perturb a planet's orbit

inward until it crosses the point of no

return. What's fascinating is that the

surviving star carries the record of what

happened to its twin's planetary family

written in its own chemistry.

Anna: As our ability to analyze stellar

compositions becomes ever more precise,

we're finding more and more binary systems

with this kind of chemical imbal, which

raises a sobering question about how

common planetary ingestion really is,

and whether our own solar system, with

Jupiter acting as a kind of gravitational

shepherd for the inner planets, has been

unusually well behaved.

Avery: Stars they can be a bit greedy sometimes,

apparently.

Anna: But on that cosmic note, it's time to wrap

up today's show.

Avery: What an episode today. A fossil from the dawn

of the Milky Way, a planet being roasted

alive, a 21 year old space telescope

getting a second chance at life, an ancient

supernova captured across four wavelengths,

a quasi moon about to give up its secrets,

and a star that ate its own planet. Not a

slow news day in space.

Anna: Never is. If you enjoyed today's show, please

do subscribe. Leave us a review and share

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looking up a little more. You'll find us

ah@astronomydaily IO and on

social media astrodaily pod. We'll

be back tomorrow with your Friday edition.

Until then, keep your eyes in the

Avery: sky and your mind in the stars. Good night

everyone.

Anna: Stories.

In this episode