Potentially the biggest scientific story in history?

[barbos]

It looks similar. But there is a significant difference in spectral data. In case of eruptive stars you can determine what was erupted from star from spectra. In case of Tabby there appears no change in spectrum which suggests something which pretty opaque/solid/dense to most light including infrared. And star itself is not variable based on its characteristics.

I think maybe you misunderstand what I was suggesting. I wasn't suggesting that it could be a R Coronae Borealis but only that it could be an irregular variable of a class we have not yet observed.

I understand, but it's highly unlikely to be new type of variable star.

 

[Don2 (Don1 Revised)]

Re this piece "Since the 19th Century, its brightness has decreased steadily by nearly 20 percent..." what kind of brightness measure did they have in the 19th century and how accurate and precise was it?

The same one they had for the 20 centuries or so prior to that:

The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements. This can be dated back to Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover Earth's precession. In doing so, he also developed the brightness scale still in use today.[1] Hipparchus compiled a catalogue with at least 850 stars and their positions.[2] Hipparchus's successor, Ptolemy, included a catalogue of 1,022 stars in his work the Almagest, giving their location, coordinates, and brightness.

 https://en.wikipedia.org/wiki/Astrometry

The Space.com article also notes that for data from the past century, photographic plates taken of the star over that time were examined. For that time period it would be a simple matter of comparing the star to other stars in the field of view, and noting the change in luminosity compared to those other stars.

See DBT's recent post:

Looks like the long term dimming may have been due to the instruments being used and not the star itself:

Quote;
''Now, however, researchers suggest this seemingly century-long dimming trend might not be real. Instead, the apparent darkening may just be due to how astronomical instruments have changed over time.

In the new study, scientists pored over DASCH (Digital Access to a Sky Century @ Harvard) data. This is a collection of more than 500,000 photographic glass plates taken by astronomers at Harvard in Massachusetts between 1885 and 1993 that the university is digitizing.

"It is exciting that we have these century-old data, which are incredibly valuable for checks like this," study lead author Michael Hippke, an amateur astronomer from the German town of Neukirchen-Vluyn, told Space.com.

''The researchers looked not only at Tabby's Star, but also at a number of comparable stars in the DASCH database. Results showed that many of these other stars experienced a drop in brightness similar to that of Tabby's Star in the 1960s.

"That indicates the drops were caused by changes in the instrumentation, not by changes in the stars' brightness," study co-author Keivan Stassun at Vanderbilt University in Nashville, Tennessee, said in a statement.''

 

[Shadowy Man]

Assuming that the glass plates have other stars in them, one would think they could ascertain if it were a real effect by comparing the brightness changes to other stars in the fields.

 

[KeepTalking]

The same one they had for the 20 centuries or so prior to that:

The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements. This can be dated back to Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover Earth's precession. In doing so, he also developed the brightness scale still in use today.[1] Hipparchus compiled a catalogue with at least 850 stars and their positions.[2] Hipparchus's successor, Ptolemy, included a catalogue of 1,022 stars in his work the Almagest, giving their location, coordinates, and brightness.

 https://en.wikipedia.org/wiki/Astrometry

The Space.com article also notes that for data from the past century, photographic plates taken of the star over that time were examined. For that time period it would be a simple matter of comparing the star to other stars in the field of view, and noting the change in luminosity compared to those other stars.

See DBT's recent post:

Looks like the long term dimming may have been due to the instruments being used and not the star itself:

Quote;
''Now, however, researchers suggest this seemingly century-long dimming trend might not be real. Instead, the apparent darkening may just be due to how astronomical instruments have changed over time.

In the new study, scientists pored over DASCH (Digital Access to a Sky Century @ Harvard) data. This is a collection of more than 500,000 photographic glass plates taken by astronomers at Harvard in Massachusetts between 1885 and 1993 that the university is digitizing.

"It is exciting that we have these century-old data, which are incredibly valuable for checks like this," study lead author Michael Hippke, an amateur astronomer from the German town of Neukirchen-Vluyn, told Space.com.

''The researchers looked not only at Tabby's Star, but also at a number of comparable stars in the DASCH database. Results showed that many of these other stars experienced a drop in brightness similar to that of Tabby's Star in the 1960s.

"That indicates the drops were caused by changes in the instrumentation, not by changes in the stars' brightness," study co-author Keivan Stassun at Vanderbilt University in Nashville, Tennessee, said in a statement.''

The article to which DBT links is 3 months older than the one to which I linked, and both are from Space.com. Though they are written by different authors they seem to be citing the same study, so I'm not sure why there is a discrepancy, but I will also note the following information from the article I linked:

In the 4 years of Kepler's primary mission, the star showed an unprecedented dimming of 3.5 percent. So not only did Kepler detect transient dips in brightness of up to 20 percent, there also seems to be a very definite downward trend in brightness throughout our observational history of the star.

No matter how you slice it, this is strange.

After studying photometric observations for other stars surrounding KIC 8462852, there's no other star that shows such dramatic behavior. What's more, there's very few known phenomena that could be causing this. So once again, astronomers are clutching at straws in an effort to explain what is going on.

 

[Shadowy Man]

In the 4 years of Kepler's primary mission, the star showed an unprecedented dimming of 3.5 percent. So not only did Kepler detect transient dips in brightness of up to 20 percent, there also seems to be a very definite downward trend in brightness throughout our observational history of the star.

No matter how you slice it, this is strange.

After studying photometric observations for other stars surrounding KIC 8462852, there's no other star that shows such dramatic behavior. What's more, there's very few known phenomena that could be causing this. So once again, astronomers are clutching at straws in an effort to explain what is going on.

Methinks this author doesn't know what the phrase "clutching at straws" means.

 

[DBT]

The same one they had for the 20 centuries or so prior to that:

The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements. This can be dated back to Hipparchus, who around 190 BC used the catalogue of his predecessors Timocharis and Aristillus to discover Earth's precession. In doing so, he also developed the brightness scale still in use today.[1] Hipparchus compiled a catalogue with at least 850 stars and their positions.[2] Hipparchus's successor, Ptolemy, included a catalogue of 1,022 stars in his work the Almagest, giving their location, coordinates, and brightness.

 https://en.wikipedia.org/wiki/Astrometry

The Space.com article also notes that for data from the past century, photographic plates taken of the star over that time were examined. For that time period it would be a simple matter of comparing the star to other stars in the field of view, and noting the change in luminosity compared to those other stars.

See DBT's recent post:

Looks like the long term dimming may have been due to the instruments being used and not the star itself:

Quote;
''Now, however, researchers suggest this seemingly century-long dimming trend might not be real. Instead, the apparent darkening may just be due to how astronomical instruments have changed over time.

In the new study, scientists pored over DASCH (Digital Access to a Sky Century @ Harvard) data. This is a collection of more than 500,000 photographic glass plates taken by astronomers at Harvard in Massachusetts between 1885 and 1993 that the university is digitizing.

"It is exciting that we have these century-old data, which are incredibly valuable for checks like this," study lead author Michael Hippke, an amateur astronomer from the German town of Neukirchen-Vluyn, told Space.com.

''The researchers looked not only at Tabby's Star, but also at a number of comparable stars in the DASCH database. Results showed that many of these other stars experienced a drop in brightness similar to that of Tabby's Star in the 1960s.

"That indicates the drops were caused by changes in the instrumentation, not by changes in the stars' brightness," study co-author Keivan Stassun at Vanderbilt University in Nashville, Tennessee, said in a statement.''

The article to which DBT links is 3 months older than the one to which I linked, and both are from Space.com. Though they are written by different authors they seem to be citing the same study, so I'm not sure why there is a discrepancy, but I will also note the following information from the article I linked:

In the 4 years of Kepler's primary mission, the star showed an unprecedented dimming of 3.5 percent. So not only did Kepler detect transient dips in brightness of up to 20 percent, there also seems to be a very definite downward trend in brightness throughout our observational history of the star.

No matter how you slice it, this is strange.

After studying photometric observations for other stars surrounding KIC 8462852, there's no other star that shows such dramatic behavior. What's more, there's very few known phenomena that could be causing this. So once again, astronomers are clutching at straws in an effort to explain what is going on.

I sometimes get the impression that some of these article writers are not aware of what has, or has not been said before, or a thorough understanding and implications of the research...they just start out fresh with a deadline to meet and pump out the required report.

 

[KeepTalking]

Methinks this author doesn't know what the phrase "clutching at straws" means.

I know what it means, but I don't understand how it pertains to the quote I provided. Can you explain why you think the author is clutching at straws there?

 

[Speakpigeon]

Or the recent rise of Dark Matter...
EB

 

[Shadowy Man]

Methinks this author doesn't know what the phrase "clutching at straws" means.

I know what it means, but I don't understand how it pertains to the quote I provided. Can you explain why you think the author is clutching at straws there?

The author isn't clutching at straws. The author claimed that scientists are clutching at straws. That would imply that the scientists are putting out crazy, desperate ideas to explain the observations. When actually, scientists are simply unsure of what is going on and how to explain it given what we think we know about stars. I just don't think "clutching at straws" explains the situation very well at all.

 

[KeepTalking]

I know what it means, but I don't understand how it pertains to the quote I provided. Can you explain why you think the author is clutching at straws there?

The author isn't clutching at straws. The author claimed that scientists are clutching at straws. That would imply that the scientists are putting out crazy, desperate ideas to explain the observations. When actually, scientists are simply unsure of what is going on and how to explain it given what we think we know about stars. I just don't think "clutching at straws" explains the situation very well at all.

Thanks for the clarification.

 

[The Colourful Jester]

http://www.sciencealert.com/researchers-just-found-a-second-dyson-sphere-star

Two of them! Now it's just getting positively mundane.

 

[barbos]

Yeah, proto-planetary disk is a best explanation.

 

[skepticalbip]

A proto-planetary disk may be a reasonable guess if only looking at data from day 1500 to day 1580:




However, it runs into problems when including the full four years of data:



It wouldn't explain the average decreasing flux, the rapid decrease in flux (day 1100 - 1300) then a return to the average decreasing flux rate, or the fact that there is no apparent repeating pattern that would be expected of clumps of preplanetary matter in orbit about the star.

 

[barbos]

Gradual decrease could be result of disk wobble and becoming thicker a we see it from the earth.
The reason they did not like proto-disk was because there were no infrared observed associated with such things. But if disk is edge on then spectrum could be very different from ordinary ones.

 

[skepticalbip]

But disk planes don't wobble. The material in the disk orbits the star in the same plane with a fixed axis of rotation. Sorta like Saturn's rings don't wobble - Saturn's axial tilt of a little over 26 degrees (the rings are in the same plane as Saturn's equator) means that as Saturn orbits the sun we can see the "top" of the rings when it is on one side of the sun and the "bottom" of the rings when it is on the other side of the sun or edge on half way between. But we can't have such a changing view of Tabby's star and its disk (if there is one).

 

[barbos]

Everything wobbles, just very slowly. And if there enough disturbance then it will wobble faster.

 

[T.G.G. Moogly]

Looks like we'll be listening in.

Dish to listen for ET around strange star

The team plans to use the 100m Green Bank Telescope in West Virginia, US, to observe the star, which is named after the leader of the team that discovered it - Tabetha Boyajian, assistant professor at Louisiana State University.

 

[bilby]

Bad news: https://amp.theguardian.com/science/across-the-universe/2018/jan/03/no-alien-megastructure-around-mysterious-tabbys-star-analysis-shows

It seems that the aliens are using stealth technology to make their space station look like a dust cloud.

 

[DBT]

A pity, dust clouds just don't have the same glamour and appeal as Alien Super civilizations...

 

[bilby]

A pity, dust clouds just don't have the same glamour and appeal as Alien Super civilizations...

Less likely to invade and enslave us all to build a super intergalactic ray-gun though.

So swings and roundabouts.