Supernova observation first of its kind using NASA satellite

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When NASA's Transiting Exoplanet Survey Satellite launched into space in April 2018, it did so with a specific goal: to search the universe for new planets.

But in recently published research, a team of astronomers at The Ohio State University showed that the survey, nicknamed TESS, could also be used to monitor a particular type of supernova, giving scientists more clues about what causes white dwarf stars to explode—and about the elements those explosions leave behind.

"We have known for years that these stars explode, but we have terrible ideas of why they explode," said Patrick Vallely, lead author of the study and an Ohio State astronomy graduate student. "The big thing here is that we are able to show that this supernova isn't consistent with having a white dwarf (take mass) directly from a standard star companion and explode into it—the kind of standard idea that had led to people trying to find hydrogen signatures in the first place. That is, because the TESS light curve doesn't show any evidence of the explosion slamming into the surface of a companion, and because the hydrogen signatures in the SALT spectra don't evolve like the other elements, we can rule out that standard model."

Their research, detailed in the Monthly Notices of the Royal Astronomical Society, represents the first published findings about a supernova observed using TESS, and add new insights to long-held theories about the elements left behind after a explodes into a supernova.

Those elements have long troubled astronomers.

A white dwarf explodes into a specific type of supernova, a 1a, after gathering mass from a nearby companion star and growing too big to remain stable, astronomers believe. But if that is true, then the explosion should, astronomers have theorized, leave behind trace elements of hydrogen, a crucial building block of stars and the entire universe. (White dwarf stars, by their nature, have already burned through their own hydrogen and so would not be a source of hydrogen in a supernova.)

But until this TESS-based observation of a supernova, astronomers had never seen those hydrogen traces in the explosion's aftermath: This supernova is the first of its type in which astronomers have measured hydrogen. That hydrogen, first reported by a team from the Observatories of the Carnegie Institution for Science, could change the nature of what astronomers know about white dwarf supernovae.

"The most interesting thing about this particular supernova is the hydrogen we saw in its spectra (the elements the explosion leaves behind)," Vallely said. "We've been looking for hydrogen and helium in the spectra of this type of supernova for years—those elements help us understand what caused the supernova in the first place."

The hydrogen could mean that the white dwarf consumed a nearby star. In that scenario, the second star would be a normal star in the middle of its lifespan—not a second white dwarf. But when astronomers measured the light curve from this supernova, the curve indicated that the second star was in fact a second white dwarf. So where did the hydrogen come from?

Professor of Astronomy Kris Stanek, Vallely's adviser at Ohio State and a co-author on this paper, said it is possible that the hydrogen came from a companion star—a standard, regular star—but he thinks it is more likely that the hydrogen came from a third star that happened to be near the exploding white dwarf and was consumed in the supernova by chance.

"We would think that because we see this hydrogen, it means that the white dwarf consumed a second star and exploded, but based on the light curve we saw from this supernova, that might not be true," Stanek said.

"Based on the light curve, the most likely thing that happened, we think, is that the hydrogen might be coming from a third star in the system," Stanek added. "So the prevailing scenario, at least at Ohio State right now, is that the way to make a Type Ia (pronounced 1-A) supernova is by having two white dwarf stars interacting—colliding even. But also having a third star that provides the hydrogen."

For the Ohio State research, Vallely, Stanek and a team of astronomers from around the world combined data from TESS, a 10-centimeter-diameter telescope, with data from the All-Sky Automated Survey for Supernovae (ASAS-SN for short.) ASAS-SN is led by Ohio State and is made up of small telescopes around the world watching the sky for supernovae in far-away galaxies.

TESS, by comparison, is designed to search the skies for planets in our nearby galaxy—and to provide data much more quickly than previous satellite telescopes. That means that the Ohio State team was able to use data from TESS to see what was happening around the supernova in the first moments after it exploded—an unprecedented opportunity.

The team combined data from TESS and ASAS-SN with data from the South African Large Telescope to evaluate the elements left behind in the supernova's wake. They found both hydrogen and helium there, two indicators that the exploding star had somehow consumed a nearby companion star.

"What is really cool about these results is, when we combine the data, we can learn new things," Stanek said. "And this supernova is the first exciting case of that synergy."

The supernova this team observed was a Type Ia, a type of supernova that can occur when two stars orbit one another—what astronomers call a binary system. In some cases of a Type I supernova, one of those is a white dwarf.

A white dwarf has burned off all its nuclear fuel, leaving behind only a very hot core. (White dwarf temperatures exceed 100,000 degrees Kelvin—nearly 200,000 degrees Fahrenheit.) Unless the star grows bigger by stealing bits of energy and matter from a nearby star, the white dwarf spends the next billion years cooling down before turning into a lump of black carbon.

But if the white dwarf and another star are in a binary system, the white dwarf slowly takes mass from the other star until, eventually, the white dwarf explodes into a supernova.

Type I supernovae are important for space science—they help astronomers measure distance in space, and help them calculate how quickly the universe is expanding (a discovery so important that it won the Nobel Prize in Physics in 2011.)

"These are the most famous type of supernova—they led to dark energy being discovered in the 1990s," Vallely said. "They are responsible for the existence of so many elements in the universe. But we don't really understand the physics behind them that well. And that's what I really like about combining TESS and ASAS-SN here, that we can build up this data and use it to figure out a little more about these supernovae."

Scientists broadly agree that the companion star leads to a white dwarf supernova, but the mechanism of that explosion, and the makeup of the companion star, are less clear.

This finding, Stanek said, provides some evidence that the companion star in this type of supernova is likely another white dwarf.

"We are seeing something new in this data, and it helps our understanding of the Ia phenomenon," he said. "And we can explain this all in terms of the scenarios we already have—we just need to allow for the third star in this case to be the source of the ."


Explore further

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More information: P J Vallely et al. ASASSN-18tb: a most unusual Type Ia supernova observed by TESS and SALT, Monthly Notices of the Royal Astronomical Society (2019). DOI: 10.1093/mnras/stz1445
Citation: Supernova observation first of its kind using NASA satellite (2019, July 16) retrieved 17 August 2019 from https://phys.org/news/2019-07-supernova-kind-nasa-satellite.html
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Jul 16, 2019
Is it possible that light can have different characteristics when your dealing with the space between galaxies instead of smaller distances? Like the space in between could be interfering somehow or light distorting at longer distances. Generally curious, thanks :D

Jul 16, 2019
The current theory of the space between galaxies is that it's mostly neutral hydrogen, which doesn't interact with light. This is a theory because it's been tested. The proper term for this space is "inter-galactic medium" (abbreviated IGM). For a good idea of what astrophysicists know about the IGM, see this Wikipedia article: https://en.wikipe...ic_space

There are three links at the beginning of the section that you should follow for more information than the brief section I've linked to.

Jul 16, 2019
The current theory of the space between galaxies is that it's mostly neutral hydrogen, which doesn't interact with light. This is a theory because it's been tested. The proper term for this space is "inter-galactic medium" (abbreviated IGM). For a good idea of what astrophysicists know about the IGM, see this Wikipedia article: https://en.wikipe...ic_space

There are three links at the beginning of the section that you should follow for more information than the brief section I've linked to.


Thankyou for the quick and informative reply!

Jul 16, 2019
You're welcome! My pleasure.

Jul 16, 2019
da schnied can't utter a word without lying. He says;
the space between galaxies is that it's mostly neutral hydrogen,

But his link states something entirely different

"It consists mostly of ionized hydrogen; i.e. a plasma"
And we all know the plasma ignoramuses misuse of plasma physics.

Jul 17, 2019
da schnied can't utter a word without lying. He says;
the space between galaxies is that it's mostly neutral hydrogen,

But his link states something entirely different

"It consists mostly of ionized hydrogen; i.e. a plasma"
And we all know the plasma ignoramuses misuse of plasma physics.


@cant you are the one misusing plasma physics

Jul 17, 2019
Of course there is a third star required. Not just any star but a "regular" star, one that shines brightly as it burns hydrogen in the main sequence.

It is merely bad luck we did not notice the third star hanging out during the last 150 years of intense study of space. The last 50 years especially since we singled out white dwarfs for study.
Darn, sneaky things these huge balls of burning hydrogen.

Jul 17, 2019
"..the white dwarf spends the next billion years cooling down before turning into a lump of black carbon."

Real dark matter!

Jul 17, 2019
Studies of the large scale distribution of galaxies show that the Universe has a foam-like structure, with groups and clusters of galaxies lying along filaments that occupy about a tenth of the total space.... Surrounding and stretching between galaxies, there is a rarefied plasma[134] that is organized in a galactic filamentary structure.[135] This material is called the intergalactic medium (IGM).


So who's lying, @cantthink69? Looks like most of it's neutral hydrogen just like I said. Only 10% of it's ionized. I've got other arguments but this one will do for now.


Jul 17, 2019
@Da Schneib
@cantdrive85.
https://en.wikipedia.org/wiki/Outer_space#Intergalactic_space

Looks like most of it's neutral hydrogen just like I said. Only 10% of it's ionized.
Careful, DS! According to my reading of your referenced wiki re Intergalactic Space, the 10% relates to the TOTAL SPACE occupied by filaments along which occur the galaxy groups/clusters, NOT the IONIZED H proportion. It goes on to say:
Surrounding and stretching between galaxies, there is a rarefied plasma[134] that is organized in a galactic filamentary structure. ... The density of the IGM is 5–200 TIMES! the average density of the Universe.[136] It consists MOSTLY of IONIZED hydrogen; ...As gas falls into the intergalactic medium FROM THE VOIDS, it heats up to temperatures of 105 K to 107 K, ... this is why the IGM is IONIZED. ...half of the atomic matter in the Universe might exist in this warm–hot, rarefied state.
Perhaps you should re-read it before you put any further arguments. :)

Jul 17, 2019
ERRATA for my last post just above:

1) Fixing link: https://en.wikipe...ic_space

2) The 5's appearing after the 10's in the following section...
temperatures of 105 K to 107 K
...are EXPONENTS and NOT part of the BASE number string per se. Which means that the temps are 100,000 K to 1000,0000 K. Hence the ionised states.

Thanks. :)

Jul 17, 2019
@RC, seems like the voids have a lot more hydrogen than the filaments. And it's all neutral or we'd be able to see it now.

Maybe you should read more carefully.

Jul 17, 2019
@Da Schneib.
@RC, seems like the voids have a lot more hydrogen than the filaments. And it's all neutral or we'd be able to see it now.

Maybe you should read more carefully.
That was not the point, mate. My post was to point out YOUR 'argument' to cantdrive85 (in which you accuse HIM of "lying") was based on your own misreading/misunderstanding of what the "10%" related to....as I explained by quoting your own referenced wiki excerpt. So, first: do you acknowledge your error re that? :)

Second, re VOIDS aspect: please recall our past discussions wherein it was ME that pointed out to YOU that the so-called 'voids' had a LOT MORE low visibility/transparent etc matter in them; in the form of atoms, molecules, dust, debris etc etc, in many energy/motion/configurational/temperature states. In light of those past discussions, your above assertion only confirms what I already said then; so your exhortation to me to read more carefully would be better directed at yourself. :)

Jul 17, 2019
Nope. I didn't make an error. You are implicitly asserting (lying) that there is nothing in cosmic voids. Again.

You always lie. Why can't you stop?

Jul 17, 2019
@Da Schneib.
Nope. I didn't make an error. You are implicitly asserting (lying) that there is nothing in cosmic voids. Again.

You always lie. Why can't you stop?
Please don't revert back to the old DS, mate. I did not assert or suggest anything of the kind, either explicitly or implicitly. The original point was you misread your own wiki and confused the 10% total space proportion (as stated in that wiki) with your own erroneous 10% ionised Hydrogen proportion 'misread take'. The readers can see that from our exchange and the quoted excerpts from your own referenced wiki. Please do not try to change the subject and project your own errors/misunderstandings onto the one (me) who pointed out your errors/misunderstandings as above. Take a break, DS, and think hard about how you proceed/respond re this, mate. No hard feelings. Good luck. :)

Jul 17, 2019
Ummmmm, @RC, the hydrogen in the filaments is coming from the voids, which you already admitted are 90% of everything.

Now stop bullshitting.

Jul 17, 2019
@Da Schneib.
Ummmmm, @RC, the hydrogen in the filaments is coming from the voids, which you already admitted are 90% of everything.

Now stop bullshitting.
That is what I have always pointed out for you in the past; and now your own wiki reference and yourself is coming round to that longstanding view of MINE. So what exactly is your basis for calling ME a liar, DS? And why have you not addressed your obvious error re your misunderstanding the 10% aspect which you erroneously applied to the proportion of ionised Hydrogen instead of the proportion of Space which the filaments occupied (as the wiki clearly stated)? Please don't lose yourself again in your own 'manufactured reality' from which you then cry 'liar' etc at me, mate. Take a break and re-thinkit. Good luck. :)

Jul 17, 2019
The hydrogen in the voids is neutral. It's only the hydrogen in the filaments that's plasma and can be detected.

You're lying again, @RC. Shall I post your lie record again?

Jul 17, 2019
@Da Schneib.
The hydrogen in the voids is neutral. It's only the hydrogen in the filaments that's plasma and can be detected.
First you made an erroneous assertion re what wiki said in your quoted excerpt re the Hydrogen in the filaments/IGM; and now you go on to make a further erroneous assertion about the state of material in the voids. Did you not know that astrophysicists have been using the light from distant QUASARS to probe the actual content/state of the intervening space along the line-of-sight between Quasars and Earth? They are finding all sorts of matter in all sorts of states, even in the so-called 'voids' through which the quasar light traversed. Just because the material is low-luminosity, and in some cases in states which do not radiate or their energy re-absorbed in the form of CHEMICAL bonds creating complex inorganic/organic compounds and in various excited states stable in such rarefied and cold environments, it doesn't mean its 'all' neutral Hydrogen. :)

Jul 17, 2019
I didn't say it was *all* neutral hydrogen.

You're lying again, @RC.

Jul 17, 2019
Thread where @112LiarRC lies about current research into cosmic voids and gets caught: https://phys.org/...ies.html
Thread where @112LiarRC makes conflicting claims within ten posts and gets caught: https://phys.org/...ome.html
Thread where @112LiarRC claims there is "REAL/PHYSICAL UNIVERSAL 'infinity'" and gets caught: https://phys.org/...rgy.html
Thread where @112LiarRC claims Rubin said galaxies will implode with out DM and confuses Zwicky with Rubin:
https://phys.org/...zzy.html
Thread where @112LiarRC claims inflation is a "religion:" https://phys.org/...ure.html

Jul 17, 2019
Studies of the large scale distribution of galaxies show that the Universe has a foam-like structure, with groups and clusters of galaxies lying along filaments that occupy about a tenth of the total space.... Surrounding and stretching between galaxies, there is a rarefied plasma[134] that is organized in a galactic filamentary structure.[135] This material is called the intergalactic medium (IGM).


So who's lying, @cantthink69? Looks like most of it's neutral hydrogen just like I said. Only 10% of it's ionized. I've got other arguments but this one will do for now.


Nowhere in your quoted text does it say anything neutral hydrogen, it only mentions "rarefied plasma" and ionized "gases". Can you read?

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