Author Topic: Boyajians Star Updates And Discussion  (Read 295790 times)

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #180 on: 05/03/2017 05:10 am »
Interesting blog post from Tabitha Boyajian.   The LCO scope and SBIG STL-6303 camera and filter set are probably up to the task of measuring the overall light curve, as well as measuring if the dimming is achromatic. 

More interesting is what the proposal for Hubble time contained.  The notion of examining the volume of space around the star seems tailored to the ISM theories.    What exact observations should they propose for Hubble?

Long duration exposures?  How long of an exposure will be needed to bring out much fainter nearby stars, as well as potentially "see" where patches of ISM may be blocking the field of view?

1.  What would they look for with the COS, NICMOS, or ACS instruments?
2.  What theories can be constrained with specific Hubble observations?
3.  What observations can provide support for predictions made by various theories?
4.  What observations can be eliminate certain theories?


Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #181 on: 05/15/2017 07:39 pm »
Quote
Are the Dyson rings around pulsars detectable?

Z. Osmanov
(Submitted on 11 May 2017 (v1), last revised 12 May 2017 (this version, v2))
In the previous paper (Osmanov 2016) (henceforth Paper-I) we have extended the idea of Freeman Dyson and have shown that a supercivilization has to use ring-like megastructures around pulsars instead of a spherical shell. In this work we reexamine the same problem in the observational context and we show that facilities of modern IR telescopes (VLTI and WISE) might efficiently monitor the nearby zone of the solar system and search for the IR Dyson-rings up to distances of the order of 0.2kpc, corresponding to the current highest achievable angular resolution, 0.001mas. In this case the total number of pulsars in the observationally reachable area is about 64±21. We show that pulsars from the distance of the order of ∼1kpc are still visible for WISE as point-like sources but in order to confirm that the object is the neutron star, one has to use the UV telescopes, which at this moment cannot provide enough sensitivity.

https://arxiv.org/abs/1705.04142

Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #182 on: 05/16/2017 06:01 am »
Why isn't a back yard commercial consumer telescope enough to detect another 20% dip in the light curve of that star? Hasn't it been something which hundreds of part time astronomers have been looking for constantly since the anomaly was announced, without finding anything to corroborate it?


I don't see how Kepler's anomaly motivates any redirection of any major telescopes or observation efforts.
« Last Edit: 05/16/2017 06:03 am by TakeOff »

Offline Stan-1967

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Re: Boyajians Star Updates And Discussion
« Reply #183 on: 05/16/2017 06:25 am »
Why isn't a back yard commercial consumer telescope enough to detect another 20% dip in the light curve of that star? Hasn't it been something which hundreds of part time astronomers have been looking for constantly since the anomaly was announced, without finding anything to corroborate it?


I don't see how Kepler's anomaly motivates any redirection of any major telescopes or observation efforts.

Major telescopes will be motivated to observe the star if another dip is detected.  Until then, the merits of any telescope time will be weighed on what the observation can measure that is interesting.   That may be the ISM or something else.  It's not up to you or I to judge, so we will see what happens. 

Offline hop

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Re: Boyajians Star Updates And Discussion
« Reply #184 on: 05/17/2017 05:29 pm »
BBC has a nice roundup on Boyajian's star http://www.bbc.com/earth/story/20170512-the-most-mysterious-star-in-the-galaxy

Nothing really new for people who have been following the story closely, but good quotes from some of the main players. It also touches on the question of why there is interest in continued observation:

Quote
In the past, the discovery of one bizarre object has often heralded a new class of phenomena. So, if history is any indication, Boyajian's Star may be just the beginning.

Offline TakeOff

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Re: Boyajians Star Updates And Discussion
« Reply #185 on: 05/18/2017 01:09 am »
BBC has a nice roundup on Boyajian's star http://www.bbc.com/earth/story/20170512-the-most-mysterious-star-in-the-galaxy

Nothing really new for people who have been following the story closely, but good quotes from some of the main players. It also touches on the question of why there is interest in continued observation:

Quote
In the past, the discovery of one bizarre object has often heralded a new class of phenomena. So, if history is any indication, Boyajian's Star may be just the beginning.
Well, it has been observed for years. And there's nothing to report.
And history tells us that one-off freak observations like this are perytons, the result of an observatory observing itself. Lots of wishful thinking going on here. When you see a shooting star, close your eyes and make magic wish. Maybe deliberately greedy media profiteering from unfounded sensationalism plays a role in the hype too.
« Last Edit: 05/18/2017 01:11 am by TakeOff »

Offline hop

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Re: Boyajians Star Updates And Discussion
« Reply #186 on: 05/18/2017 04:07 am »
Well, it has been observed for years. And there's nothing to report.
The time it has been observed is significantly less that the steady phases between dips in the Kepler light curves, and we have no idea how long it was steady before the first dip.
Quote
And history tells us that one-off freak observations like this are perytons, the result of an observatory observing itself.
This is simply not correct. History is full of "weird" observations that have turned out to be mistakes, and also ones that have turned out to be real phenomena. In the case of perytons, it was suspected quite early that they were of terrestrial origin, and RFI in general was known to be capable of producing similar signals. On the other hand, FRBs are superficially similar but were suspected to be astrophysical and have proven so.

In the case of Boyajian's star, no one has a come up with a remotely credible way for instrumental error to explain the actual data. The long term dimming also provides independent, highly suggestive evidence that there is something weird about the star.

As long as the phenomena is unexplained, it's certainly reasonable not to dismiss instrumental error entirely, but to be more than idle speculation, it would need a specific theory consistent with the actual characteristics of the instrument and the data. No one has come up with one yet.

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #187 on: 05/19/2017 11:37 am »
Well, things are getting interesting: https://twitter.com/Astro_Wright/status/865528682114203648

Quote
ALERT: @tsboyajian's star is dipping This is not a drill. Astro tweeps on telescopes in the next 48 hours: spectra please!

Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #188 on: 05/19/2017 12:20 pm »
Well, things are getting interesting: https://twitter.com/Astro_Wright/status/865528682114203648

Quote
ALERT: @tsboyajian's star is dipping This is not a drill. Astro tweeps on telescopes in the next 48 hours: spectra please!

Yes, Tabby has also tweeted about this:

https://twitter.com/tsboyajian/status/865530700128075780

2% r' band, still in ingress:
https://twitter.com/tsboyajian/status/865542587087601665

--- Tony
« Last Edit: 05/19/2017 12:21 pm by jebbo »

Offline Alpha_Centauri

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Re: Boyajians Star Updates And Discussion
« Reply #189 on: 05/19/2017 12:55 pm »
Yay, finally!

Offline as58

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Re: Boyajians Star Updates And Discussion
« Reply #190 on: 05/19/2017 12:57 pm »
I'd guess people have ToO programs at several telescopes for this? Or maybe there's some frenetic DDT proposal writing going on.

Offline jebbo

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Re: Boyajians Star Updates And Discussion
« Reply #191 on: 05/19/2017 01:07 pm »
I suspect both.  BTW, worth noting that this definitively rules out instrumentation error ...

Edit: definitely both; Tabby is asking about DDT turnaround times for SOPHIA :-)

--- Tony
« Last Edit: 05/19/2017 01:08 pm by jebbo »

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #192 on: 05/19/2017 01:14 pm »
Their was a recent paper on this but it's behind a paywall. Luckily someone on Reddit summed it up.

Quote
Am I understanding correctly then that the 800 dip can be explained as a regular shaped object passing in front of the star, but that the ingress and egress halves look different due to the object picking up speed as it slingshots around the star, and so completing the egress faster than the ingress?

Am I also understanding correctly that the authors calculate the orbital speed to be too slow assuming the object is so close to the star? How did they reach these conclusions? What are the starting assumptions for the supposed transiting object?

You can find complete discussion of the paper here.

https://www.reddit.com/r/KIC8462852/comments/6a9tdc/new_paper_the_hypothetical_orbit_of_kic_8462852b/

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #193 on: 05/19/2017 01:15 pm »
I'd guess people have ToO programs at several telescopes for this? Or maybe there's some frenetic DDT proposal writing going on.

Tabby appears to have re-tweeted Jason's & her alerts to a number of other observatories.

Here's the list.

https://mobile.twitter.com/tsboyajian/status/865542587087601665/people
« Last Edit: 05/19/2017 01:17 pm by Star One »

Offline Alpha_Centauri

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Re: Boyajians Star Updates And Discussion
« Reply #194 on: 05/19/2017 01:29 pm »
Twitter would go down today of all days. Been trying to contact people to get the message out.

« Last Edit: 05/19/2017 01:29 pm by Alpha_Centauri »

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #195 on: 05/19/2017 01:30 pm »
Twitter would go down today of all days. Been trying to contact people to get the message out.

It's the aliens I tell you!

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #196 on: 05/19/2017 02:14 pm »
New Tweet from Tabby.

Quote
Tabetha Boyajian @tsboyajian

Hey @SOFIAtelescope what is the turn around time for a DDT?  #TabbysStar is acting up right now! @AllPlanets

https://mobile.twitter.com/tsboyajian/status/865554450089353216

Offline Orbiter

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Re: Boyajians Star Updates And Discussion
« Reply #197 on: 05/19/2017 02:23 pm »
Wow. Hopefully we can get some more obs soon.

Quote
Tabetha Boyajian @tsboyajian
Replying to @ajebson and 10 others
its 2% in r' band and looks like its the start
« Last Edit: 05/19/2017 02:28 pm by Orbiter »
KSC Engineer, astronomer, rocket photographer.

Offline Star One

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Re: Boyajians Star Updates And Discussion
« Reply #198 on: 05/19/2017 02:28 pm »
That's just the leading edge so to speak I imagine of whatever it is as seen from our viewpoint.

Offline notsorandom

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Re: Boyajians Star Updates And Discussion
« Reply #199 on: 05/19/2017 02:32 pm »
From a Reddit thread (here) Dr. Boyajian explained why there might be a dip in late April 2017:
Quote
The prediction simply comes from the assumption that the two large dips seen in the kepler data are from the same orbiting object (though the dip profiles look nothing alike, it is the best we have to work with). So if dip 1 occurred at Kepler day 792 and the middle of the large complex of dips is day 1540, then the orbital period would be the difference between these: 748 days. Therefore, IF the dips 1 and 2 come from the same orbiting source, then we would expect the 3rd big dip at (1540+748)=2288 days and the 4th to be at (2288+748) = 3036 days. Then add 2454833 to convert "kepler day" to "Barycentric Julian day", we get time for the predicted dip 4 at BJD=2457869. Last step is to use the JD converter to figure out what this means to anyone but a computer :). http://aa.usno.navy.mil/data/docs/JulianDate.php We were not monitor the sky when dip#3 would have occurred in April of 2015, but dip 4 is predicted to be at the end of April, 2017. Again, this all lies on the assumption that the large dips we see are from the same object passing in front of us and the star - and this is not necessarily the case. But for now, this is the best guess. ~Tabby
So we are seeing this dip only a little later than expected! I know three data points do not make a trend and this is not (yet) nearly as large of a dip. However if we are seeing this phenomenon repeat then it almost has to be something in orbit around the star thus ruling out an explanation involving something in interstellar space.

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