| |
EI2GYB > ASTRO 09.10.25 12:01l 137 Lines 7687 Bytes #999 (0) @ WW
BID : 46356_EI2GYB
Read: GUEST
Subj: Webb unveils doomed star that could help solve mystery
Path: DB0FHN<DB0FFL<OE2XZR<OE6XPE<UA6ADV<I0OJJ<IR0AAB<VE3TOK<VE3CGR<GB7OSW<
GB7BED<DM4RW<EI2GYB
Sent: 251009/0948Z @:EI2GYB.DGL.IRL.EURO #:46356 LinBPQ6.0.25
#####
_ _ _ _ #### _\_
/ \ ___| |_ _ __ ___ | \ | | _____ _____ ##=-[.].]
/ _ \ / __| __| '__/ _ \ | \| |/ _ \ \ /\ / / __| #( _\
/ ___ \\__ \ |_| | | (_) | | |\ | __/\ V V /\__ \ # \__|
/_/ \_\___/\__|_| \___/ |_| \_|\___| \_/\_/ |___/ \___/
.' `.
+------------------------------------------------------------------------------+
Webb unveils doomed star that could help solve mystery of missing massive red
supergiants
A Northwestern University-led team of astronomers has captured the most
detailed glimpse yet of a doomed star before it exploded. Using NASA's James
Webb Space Telescope (JWST), the international team identified a supernova's
source star, or progenitor, at mid-infrared wavelengths for the first time.
These observations-combined with archival images from the Hubble Space
Telescope-revealed the explosion came from a massive red supergiant star,
cloaked in an unexpected shroud of dust.
The discovery may help solve the decades-old mystery of why massive red
supergiants rarely explode. After all, theoretical models predict red
supergiants should make up the majority of core-collapse supernovae. The new
study shows these stars do explode but are simply hidden out of sight, within
thick clouds of dust. With JWST's new capabilities, astronomers can finally
pierce through the dust to spot these phenomena, closing the gap between theory
and observation.
The study appears in The Astrophysical Journal Letters. It marks the JWST's
first detection of a supernova progenitor.
"For multiple decades, we have been trying to determine exactly what the
explosions of red supergiant stars look like," said Northwestern's Charlie
Kilpatrick, who led the study. "Only now, with JWST, do we finally have the
quality of data and infrared observations that allow us to say precisely the
exact type of red supergiant that exploded and what its immediate environment
looked like. We've been waiting for this to happen-for a supernova to explode
in a galaxy that JWST had already observed. We combined Hubble and JWST data
sets to completely characterize this star for the first time."
An expert on the lives and deaths of massive stars, Kilpatrick is a research
assistant professor at Northwestern's Center for Interdisciplinary Exploration
and Research in Astrophysics. Aswin Suresh, a graduate student in physics and
astronomy at Northwestern's Weinberg College of Arts and Sciences and member of
Kilpatrick's research group, is a key co-author on the paper.
Reddest, dustiest progenitor ever observed
Using the All-Sky Automated Survey of Supernovae, astronomers first detected
the supernova, dubbed SN2025pht, on June 29, 2025. Its light had traveled from
a nearby galaxy called NGC 1637, located 40 million light-years away from Earth.
By comparing Hubble and JWST images of NGC 1637 from before and after the
star's explosion, Kilpatrick, Suresh and their collaborators found SN2025pht's
progenitor star. It was immediately striking-extremely bright and incredibly
red. Although the star shined about 100,000 times brighter than our sun,
surrounding dust obscured much of this light. The dusty veil was so thick, in
fact, that the star appeared more than 100 times dimmer in visible light than
it would appear without the dust. Because dust blocked out shorter, bluer
wavelengths of light, the star also appeared surprisingly red.
"It's the reddest, dustiest red supergiant that we've seen explode as a
supernova," Suresh said.
Massive stars in the late stages of their lives, red supergiants are among the
largest stars in the universe. When their cores collapse, they explode as Type
II supernovae, leaving behind either a neutron star or black hole. The most
familiar example of a red supergiant is Betelgeuse, the bright reddish star in
the shoulder of the constellation Orion.
"SN2025pht is surprising because it appeared much redder than almost any other
red supergiant we've seen explode as a supernova," Kilpatrick added. "That
tells us that previous explosions might have been much more luminous than we
thought because we didn't have the same quality of infrared data that JWST can
now provide."
Clues hidden in dust
The deluge of dust could help explain why astronomers have struggled to find
red supergiant progenitors. Most massive stars that explode as supernovae are
the brightest and most luminous objects in the sky. So, theoretically, they
should be easy to spot before they explode. But that hasn't been the case.
Astronomers posit that the most massive aging stars also might be the dustiest.
These thick cloaks of dust might dim the stars' light to the point of utter
undetectability. The new JWST observations support this hypothesis.
"I've been arguing in favor of that interpretation, but even I didn't expect to
see such an extreme example as SN2025pht," Kilpatrick said. "It would explain
why these more massive supergiants are missing because they tend to be dustier."
In addition to the presence of dust itself, the dust's composition was also
surprising. While red supergiants tend to produce oxygen-rich, silicate dust,
this star's dust appeared rich with carbon. This suggests that powerful
convection in the star's final years may have dredged up carbon from deep
inside, enriching its surface and altering the type of dust it produced.
"The infrared wavelengths of our observations overlap with an important
silicate dust feature that's characteristic of some red supergiant spectra,"
Kilpatrick said. "This tells us that the wind was very rich in carbon and less
rich in oxygen, which also was somewhat surprising for a red supergiant of this
mass."
A new era for exploding stars
The new study marks the first time astronomers have used JWST to directly
identify a supernova progenitor star, opening the door to many more
discoveries. By capturing light across the near- and mid-infrared spectrum,
JWST can reveal hidden stars and provide missing pieces for how the most
massive stars live and die.
The team is now searching for similar red supergiants that may explode as
supernovae in the future. Observations by NASA's upcoming Nancy Grace Roman
Space Telescope may help this search. Roman will have the resolution,
sensitivity and infrared wavelength coverage to see these stars and potentially
witness their variability as they expel out large quantities of dust near the
end of their lives.
"With the launch of JWST and the upcoming Roman launch, this is an exciting
time to study massive stars and supernova progenitors," Kilpatrick said. "The
quality of data and new findings we will make will exceed anything observed in
the past 30 years."
+------------------------------------------------------------------------------+
================================================================================
= ____ __ ____ ___ _ _ ____ ____ ____ ____ =
= ( __)( )(___ \ / __)( \/ )( _ \ ( _ \( _ \/ ___) =
= ) _) )( / __/( (_ \ ) / ) _ ( ) _ ( ) _ (\___ \ =
= (____)(__)(____) \___/(__/ (____/ (____/(____/(____/ =
= Serving The Irish Packet Radio Network Since 2006 =
= Packet: EI2GYB@EI2GYB.DGL.IRL.EURO / EI2GYB@WINLINK.ORG =
= Email/PayPal: EI2GYB@GMAIL.COM =
================================================================================
Read previous mail | Read next mail
| |
