S27E47: Stellar Nurseries: Unveiling the Origins of Brown Dwarfs and Starbursts

[00:00:00] This is SpaceTime Series 27 Episode 47 for broadcast on the 17th of April 2024.

[00:00:06] Coming up on SpaceTime, new research shows that brown dwarves are far more star-like than

[00:00:12] previously thought. Astronomers expecting a nova event before the end of this year.

[00:00:18] And we look at the extreme starburst galaxy M82. All that and more coming up on SpaceTime.

[00:00:25] Welcome to SpaceTime with Stuart Gary.

[00:00:46] A new study suggests that brown dwarves are created through the same processes as stars

[00:00:51] and not like planets. Brown dwarves are failed stars which don't have enough mass to trigger

[00:00:56] the core nuclear fusion process which makes stars like our sun shine. They fit into a category between

[00:01:03] the largest planets which are about 13 times the mass of Jupiter and the smallest spectral type M

[00:01:08] red dwarf stars which are about 75 to 80 times the mass of Jupiter or about 0.08 solar masses.

[00:01:15] However some brown dwarves start out their lives as red dwarf stars.

[00:01:20] However as they age they burn through so much of their core nuclear fusion material

[00:01:24] that they lose the mass needed to generate the pressures and temperatures which trigger and

[00:01:29] maintain nuclear fusion. Consequently they cease being stars and instead become brown dwarves.

[00:01:36] And really when you think about it that should have been the first clue.

[00:01:39] Stars are born through the gravitational collapse of cold dark molecular gas and dust clouds.

[00:01:46] On the other hand planets are formed by the accretion of gas and dust through static electricity

[00:01:51] into ever larger clumps which eventually have enough gravity to attract other clumps and become

[00:01:56] protoplanetary bodies which then continue to grow through accretion until they clear out their

[00:02:01] orbits in the protoplanetary disk and become fully fledged planets. The new observations

[00:02:06] reported in the monthly notices of the Royal Astronomical Society show that brown dwarves

[00:02:11] are created by the same complex spiral and streamer gas structures as stars.

[00:02:16] These structures are known as feeding filaments because they feed the gaseous material from

[00:02:21] the surroundings to the newly born stars sort of like cosmic umbilical cords. The new observations

[00:02:27] provide fresh insights into whether the birth of a giant planet takes a similar course to that

[00:02:32] of a star. Before now scientists didn't know whether brown dwarves form in the same way

[00:02:38] as sun-like stars or not. A test of this hypothesis requires high sensitivity and

[00:02:43] high angular resolution observations of the brown dwarves during their earliest formation stages.

[00:02:49] To accomplish this the authors used ALMA, the Atacama Large Millimetre Sub-Millimeter

[00:02:54] Array Radio Telescope in Chile to study an extremely young brown dwarf known as Sir M16

[00:03:00] located in the northern tip of the constellation Serpent. The studies lead author Vasma

[00:03:07] Riaz from the University Observatory Munich says his observations revealed spectacular large scale

[00:03:12] spiral and streamer-like structures that have never been seen before heading towards a newly born

[00:03:18] brown dwarf. The filaments cover a vast area about 2,000 to 3,000 astronomical units and

[00:03:24] are connected directly to Sir M16. An astronomical unit is the average distance between the sun

[00:03:30] and the earth, about 150 million kilometers or 8.3 light minutes or if you prefer 8 light minutes

[00:03:37] and 13 light seconds. Riaz says further clumps of matter were also seen around the object which

[00:03:43] themselves could potentially evolve into other young brown dwarves. These observations show for

[00:03:49] the first time the influence of the external environment which results in asymmetric mass

[00:03:53] accretion via feeding filaments onto a brown dwarf in the making. The spiral structures

[00:03:59] and streamers provide important clues about how brown dwarves form. The authors simulated possible

[00:04:05] scenarios and then compared these with the data from the Alma Observatory. They found the large

[00:04:11] structures could be explained by collisions of collapsing clumps within a star-forming region.

[00:04:16] For this to occur such collisions would need have happened at least once during the lifetime

[00:04:21] of the star-forming core. The author's numerical simulation showed that these collisions would

[00:04:26] trigger the collapse of even small clumps to form brown dwarves. Spirals and streamers of various

[00:04:32] sizes and morphologies formed due to the collisions happening sideways and not head on.

[00:04:37] If the model is correct it implies a dynamic brown dwarf formation process similar to sun-like

[00:04:43] stars where chaotic interactions in the star-forming environment are common place from an early

[00:04:48] stage. Now in another scenario possibility the simulation showed that the observed structures

[00:04:54] correspond to the large pseudo-disc around a very young brown dwarf where the pseudo-discs

[00:04:59] been twisted by the rotation of the brown dwarves core in the presence of a strong magnetic field.

[00:05:05] If this model is correct it means the magnetic field plays an important role in the brown dwarves

[00:05:09] formation process. A comparison of the actual observations with the models supports a gravitational

[00:05:15] in-force scenario which can explain the asymmetric mass accretion seen in the shape

[00:05:20] of the spirals and streamers. Exactly the same as what's seen around forming stars.

[00:05:26] This is space-time. Still to come astronomers expecting a nova event before the end of the

[00:05:32] year and we examine the extreme starburst galaxy Messier 82. All that and more still to come

[00:05:39] on space-time.

[00:05:50] Astronomers are expecting a distant star to explode in a spectacular event called a nova

[00:06:01] sometime between now and September. The once-in-a-lifetime event involves a type of star known as a

[00:06:07] white dwarf in a binary system in the constellation Croneborialis the Northern Crown located some

[00:06:13] 3000 light-years away. The binary system is normally far too faint to be seen with the unaided eye

[00:06:20] but every 80 years or so the white dwarf pulls off so much material from its nearby companion star

[00:06:26] red giant that it triggers a spectacular explosion called a nova or new star on the white dwarf

[00:06:31] surface. Now this massive thermo-nuclear explosion isn't powerful enough to destroy the

[00:06:37] white dwarf but it's bright enough to be clearly visible from Earth. In fact it'll be the

[00:06:42] third time that humans have witnessed this event from the same star since it was first discovered

[00:06:46] by Irish astronomer John Birmingham back in 1866 then reappeared in 1946. The studies lead author

[00:06:54] Summer Starfield and yes that is his real name from the Arizona State University says there are

[00:06:59] only around 10 recurring novae in the Milky Way and surrounding galaxies. He says novae usually

[00:07:05] explode maybe once every 100,000 years but recurrent novae repeat their outbursts on human

[00:07:11] time scales. So what are we talking about here? Well white dwarves are the exposed stellar cores

[00:07:18] of sun-like stars that have run out of fuel. See a star shines by fusing hydrogen into helium

[00:07:24] in its core. Eventually it'll run out of core hydrogen and so the fusion process stops and

[00:07:29] the stellar core starts to contract. Now as it contracts it causes pressures and temperatures

[00:07:35] to increase in the core until eventually things get hot and tight enough for fusion to reignite

[00:07:41] this time fusing the helium in the core into carbon and oxygen. Now at the same time a very

[00:07:46] thin layer of hydrogen on the outside of the core also begins burning causing the stars out of

[00:07:51] gaseous envelope to heat up and expand. Now because the surface of this bloated stellar

[00:07:57] envelope is now much further away from the core it actually gets cooler. That means it turns

[00:08:02] redder turning the star into what we call a red giant. Eventually the star will run out of core

[00:08:07] helium and because it's not massive enough to fuse the carbon and oxygen it's made into

[00:08:12] heavier elements the star dies. The outer envelope eventually floats away from the core

[00:08:18] as a spectacular ball of gas and dust caught a planetary nebula leaving the stars

[00:08:22] white-heart stellar core exposed as a white dwarf which we left to slowly cool over the aeons.

[00:08:30] This will be the ultimate fate of our sun in around 7 billion years from now.

[00:08:35] However if the white dwarf is close enough in the binary system to its companion star it can

[00:08:40] start to gravitationally suck material from that companion star. This will gradually build up on

[00:08:45] the surface of the white dwarf until it reaches a critical mass and explodes as a nova. Then

[00:08:50] the process starts over again. But exactly when it reaches critical mass? Well that's the $64 question.

[00:08:58] This is space time. Still to come astronomers discover the starburst galaxy messier 82 is

[00:09:05] manufacturing new stars 10 times faster than the Milky Way and later in the science report

[00:09:11] a new study says homosexual behavior may have developed in mammals several times because

[00:09:16] it plays a crucial role in social bonding. All that and more still to come on space time.

[00:09:37] Astronomers have discovered that the starburst galaxy messier 82 is manufacturing new stars

[00:09:43] some 10 times faster than the Milky Way. Located 12 million light years away in the constellation

[00:09:49] Ursa Major, M82 is relatively compact in size but has been shown to host a frenzy of star-forming

[00:09:56] activity. Astronomers made the discovery using NASA's James Webb Space Telescope's

[00:10:01] near infrared camera which they were using to study the galaxy's center in far greater

[00:10:05] detail than ever previously possible. The study's lead author Alberto Bellardo from

[00:10:10] the University of Maryland says M82 has garnered a variety of observations over the years

[00:10:15] because it can be considered a prototypical starburst galaxy. Starburst simply means the

[00:10:20] galaxy is making lots and lots of new stars. Star formation continues to maintain a sense

[00:10:26] of mystery for scientists because it's shrouded by curtains of gas and dust,

[00:10:31] creating an obstacle for observing the process. Both NASA's Spitzer Space Telescope and the

[00:10:36] Hubble Space Telescope have previously observed the same galaxy but it took Webb's infrared

[00:10:42] abilities to peer through the veil of gas and dust allowing scientists to study the very center

[00:10:48] of the galaxy. The observations reported in the astrophysical journal show clumpy tendrils

[00:10:53] extending above and below the galaxy's plane. These gaseous streamers are actually galactic

[00:10:59] winds rushing out from the core of the galaxy and triggering starbursts. One area of focus

[00:11:05] was understanding how this galactic wind, which is caused by the rapid rate of star formation

[00:11:10] and subsequent supernova activity, is being launched and influencing the surrounding environment.

[00:11:16] By resolving the central region of M82, scientists could examine where the wind originates

[00:11:21] in the process gaining an insight into how hot and cold components interact within the wind.

[00:11:26] Webb was able to trace the structure of the galactic wind through its emissions of

[00:11:30] sooty chemical molecules known as polycyclic aromatic hydrocarbons or PAHs. PAHs can sort of

[00:11:37] be considered as very small dust grains that survive in cooler temperatures but are destroyed in

[00:11:42] hot conditions. Much to the team's surprise, Webb's view of the PAH emissions highlights the

[00:11:48] galactic wind's fine structure, an aspect previously unknown. The filament emissions

[00:11:53] extend away from the central region with a heart of the star formations located.

[00:11:58] Another unanticipated find was the similar structure between the PAH emissions and that of

[00:12:03] hot ionised gas. Bilalho says he was unexpected to see PAH emissions resemble ionised gas because PAHs

[00:12:10] are not supposed to live very long when exposed to such strong radiation fields, so perhaps they're

[00:12:15] being replenished all the time. The discovery challenges theories and shows that further

[00:12:20] investigation is needed. In fact, Webb's observations of M82 in the near-infrared are

[00:12:26] sparing further questions about star formation, some of which the authors hope to answer with

[00:12:30] additional data gathered from another starburst galaxy. To other papers from the same team,

[00:12:36] this time characterising the stellar clusters and correlations among the components of the wind

[00:12:40] of M82 are now almost ready for publication. In the near future, the authors will also

[00:12:46] have spectroscopic observations of M82 from Webb available for their analysis,

[00:12:51] as well as complementary large-scale images of the galaxy and its winds.

[00:12:55] The spectral data will help astronomers determine accurate ages for the star clusters

[00:13:00] and provide a sense of timing for how long each phase of star formation lasts in the starburst

[00:13:05] galaxy environment. This report from NASA TV.

[00:13:10] NASA's James Webb Space Telescope has taken a new look at the starburst galaxy,

[00:13:16] Messier 82. This galaxy hosts a lot of star formation activity, sprouting new stars

[00:13:23] 10 times faster than our own Milky Way. Star formation is hidden by dense curtains of dust

[00:13:29] and gas, but Webb can see through these murky conditions by peering an infrared light.

[00:13:34] Webb's near-infrared camera or near-cam pointed toward the starburst galaxy centre

[00:13:39] to get a better look at a vibrant community of new stars in unprecedented detail.

[00:13:44] Clumpy red tendrils can be seen extending above and below the galaxy's plane.

[00:13:49] Dark brown groupings of heavy dust are threaded throughout M82's glowing white core, even in

[00:13:55] infrared view. Looking closer toward the centre, small green specks represent concentrated areas

[00:14:02] of iron, most of which are the dense remains of exploded stars called supernova remnants.

[00:14:08] Small patches that appear red signify regions where molecular hydrogen is being lit up

[00:14:14] by a nearby young star's radiation. Using Webb to inspect the activity in galaxies like these

[00:14:21] can deepen astronomers' understanding of the early universe by getting a closer look at the

[00:14:26] physical conditions that foster the formation of new stars. This Space Time

[00:14:44] And time that I take another brief look at some of the other stories making news in science this

[00:14:52] week with a science report. A new study claims homosexual behaviour may have evolved repeatedly

[00:14:59] in mammals because it plays an important role in social bonding and reducing conflict.

[00:15:04] The findings reported in the journal Nature Communications looked at previous studies and

[00:15:09] traced the evolution of the behaviours while also looking at relationships with other behaviours.

[00:15:14] They found that same-sex sexual behaviours are widespread across over 1500 mammal species,

[00:15:20] including bonobos, chimpanzees, big horn sheep, lions, wolves and wild goats. It's seen in both

[00:15:27] females and males and appears to have multiple independent origins, but is most likely to

[00:15:33] evolve in social species, especially in species that often have adult males killing other

[00:15:38] adult males. The team suggests that homosexual behaviour may have been an adaption to

[00:15:43] reduce risks of violent conflicts and maintain positive relationships. These results can't be

[00:15:49] extended to humans according to the authors who say the study only looked at short-term

[00:15:53] courtships rather than more permanent sexual preferences. A new study has found that 40%

[00:16:01] of the world's coastlines have seen a significant increase in simultaneous heat waves in extreme

[00:16:06] sea level rise, especially in tropical regions such as the Pacific Islands.

[00:16:11] A report in the journal Communications Earth and Environment claims that under a

[00:16:15] high-emissions scenario, global coastlines could on average experience 38 days of

[00:16:20] simultaneous heat waves in extreme sea levels each year between 2025 and 2049.

[00:16:27] That compares to just seven days per year between 1989 and 2013.

[00:16:34] Canadian researchers checking up on the TV, computer and video game usage of kids during

[00:16:39] their teenage years have found a potential link to psychotic experiences.

[00:16:44] A report in the Journal of the American Medical Association found that teens who

[00:16:47] played video games a lot and those who increased and then decreased their computer

[00:16:52] usage during their teenage years were more likely to experience a psychotic episode.

[00:16:57] The researchers found that this link listened slightly for video gaming when they adjusted

[00:17:01] for mental health and interpersonal problems at age 12, but the link didn't change for

[00:17:06] computer use. Samsung's launched its new 2024 range of TVs, including a new 98-inch mega-screen

[00:17:14] with a mega-price range to match. With the details, we're joined by technology editor

[00:17:20] Alex Sahar of Roit from TechAdvice.Live. Yes, well they've got three different models.

[00:17:24] The cheapest one is $6,755. They're crystal UHD 4K smart TV. Then they have a 98-inch QLED

[00:17:32] model, also 4K. That one's $11,649 Australian dollars and the most expensive one is the Neo QLED

[00:17:39] 4K, the QN90D, the top of the range model. It's $15,172 Australian dollars.

[00:17:46] Question without notice. It wasn't all that many years ago that we were told that TVs were

[00:17:51] actually listening to our conversations so they could report back to their masters what we

[00:17:55] like to watch on TV. Is that still going on? As far as I know it is. Yeah, there are

[00:17:59] features inside the TV that allow the TV manufacturers to see what it is you're watching,

[00:18:04] whether it's free-to-wear or streaming. There was talk that Vizio, a brand that's well-known in the U.S.,

[00:18:11] that they were making more money from selling this data than they were from selling the actual

[00:18:15] TVs. If you go into the settings of your TV, the smart TV operating system that your computer

[00:18:20] has, then there's a way of switching off the sending of this information back to the manufacturer

[00:18:25] who really shouldn't be spying on you. In fact, we used to have cameras inside of the TVs,

[00:18:30] which was very much a big brother George Orwell-style scenario. Your TV.

[00:18:34] And well, we don't have cameras inside of our TVs anymore. I mean, you can actually

[00:18:38] attach a camera to some TV so that you can do Skype calls. Yeah, but the TV's, it used to

[00:18:43] have that. In fact, I remember a famous story when former Prime Minister Tony Abbott was

[00:18:48] visiting China and they saw that there was a TV there and they unplugged it and

[00:18:53] turned it off. Somebody came to the door for room service and they sort of turned the TV back on

[00:18:57] and they realized, hang on something's not right here. So they actually unplugged the TV and took

[00:19:01] it outside the room because the TV was being used as a way to listen into the private

[00:19:06] conversations. At least that was the story. I can verify that it did happen. Yeah, well,

[00:19:10] there you go. And the modern TVs do have these much fancier processes inside just like

[00:19:14] your smartphone has a newer processor every year. I mean, the top of the line one

[00:19:18] in the Samsung TV is the NQ8 AI Gen 3 processor. And this is obviously better than the Gen 2 that

[00:19:25] I had last year. And there's a lot of these AI features inside monitor for playing games.

[00:19:30] And if 98 inches isn't enough for you, you can go to 110 inches with high sense.

[00:19:36] Yes. Now, high sense is another one of the big manufacturers. This one is from China.

[00:19:39] And they also on the same day that Samsung launched their TVs, they launched a range of TVs

[00:19:43] too. Now most of them are going to come out in May, whereas most of Samsung's available

[00:19:47] right now, but they have a 110 inch TV that's coming. Now the price of that has not yet been

[00:19:53] announced, but their 85 inch TV is $8999 Australian dollars. So we don't yet know

[00:20:00] what this 110 inch TV will be, but that 100 inch TV, which is two inches bigger than the Samsung

[00:20:06] and LG models that are also at this 98 inch size, that's $6,999. And high sense actually

[00:20:12] boasts of having IMAX certification as well as Dolby Vision IQ and all the other things they have

[00:20:17] in their flagship models. But one thing of note, high sense did not mention the word AI anywhere

[00:20:22] that I can see in its press release. Presumably there are technologies in the background too,

[00:20:27] against mood and motion when you're watching sport and improve all sorts of things when

[00:20:31] you're watching movies. But interestingly, high sense didn't mention AI, whereas Samsung and LG

[00:20:36] have mentioned that very much so in their 2024 ranges. Speaking of AI, Swan has a new home security

[00:20:43] system that's just loaded with AI. Yes, Swan is an Australian security company based in Melbourne

[00:20:48] that they sell all over the world. And they've got this new AI driven home shield, they're calling

[00:20:53] it the future of smart home security as you would imagine. And they have an AI driven voice

[00:20:58] assistant, which actually will answer the door for you when someone pushes the doorbell and

[00:21:03] whether it's an Australian accent or a US accent or a bunch of other accents will actually appear to

[00:21:08] be somebody at home answering your questions, telling you where to put packages or just giving you

[00:21:13] human like responses. And it's all driven by the Amazon backend, something called Amazon Bedrock.

[00:21:18] Now Amazon has invested four billion US dollars into a company called Anthropic,

[00:21:22] who has a system called Claude, which is now version three. And it's a big competitor

[00:21:27] to open AI's chat GPT in Google's Gemini. One of the demos that I saw, which was recorded

[00:21:32] by somebody who was at CES, was talking to this doorbell, pushed the doorbell and saying,

[00:21:36] look, I've got a package for you. And his voice, which sounds very human saying, oh yeah,

[00:21:40] we'll just leave it by the front door. I'll come down and get it a bit later.

[00:21:42] Somebody else said, oh, I want to sell you something. And the voice said, no,

[00:21:45] look, I'm not in the market for that. Thanks very much.

[00:21:47] But this technology has been around for years, didn't we see it in Ferris Bielder's day off?

[00:21:54] Who is it?

[00:21:54] It's Ned Rooney, Ferris. I'd like to have a word with you.

[00:21:58] Oh, I'm sorry. I can't come to the door right now. I'm afraid that in my weak condition,

[00:22:04] I could take a nasty spill down the stairs and subject myself to further school absences.

[00:22:08] Save it, Ferris. Come down here.

[00:22:10] You can reach my parents if they're places of business. Thank you for stopping by.

[00:22:15] I appreciate your concern for my well being.

[00:22:18] I am not leaving until you come down and talk to me, Ferris.

[00:22:21] Have a nice day.

[00:22:23] You're in big trouble, Buster. Get down here, Ferris.

[00:22:27] Daddy!

[00:22:33] Who is it?

[00:22:33] Oh, God damn well who it is.

[00:22:35] Oh, I'm sorry. I can't come to the door right now.

[00:22:37] Well, from memory, he was using a voice recording of himself on a tape recorder,

[00:22:41] and it was when the doorbell was being pushed, the system was playing a tape recording

[00:22:45] of him coughing and spluttering and saying that he was sick.

[00:22:48] And the principle was really...

[00:22:48] It was the principle of how hard you love this.

[00:22:51] Oh, no. It was absolutely...

[00:22:53] No question about that.

[00:22:54] But these days, AI can convincingly simulate a human.

[00:22:58] And the whole idea of this system is that it's going to make somebody think

[00:23:03] that there's somebody at home.

[00:23:04] That's Alex Sahara of Royte from TechAdvice. Start live.

[00:23:20] And that's the show for now.

[00:23:50] Radio and TuneIn Radio.

[00:24:20] Radio and TuneIn Radio.

[00:24:50] You've been listening to Space Time with Stuart Gary.

[00:24:53] This has been another quality podcast production from Bytes.com.