Starship Asterisk*

[quote="MarkBour"]

As to the second video, so, Jack Lemmon is kind of like a jet that often blows off some of the accretion in a steadier release, whereas Walter Matthau occasionally lets loose with a full-on nova, right?[/quote]
It was a close symbiotic relationship of an odd couple and their ups & downs.

The video that Art shared had some very nice imagery. Watching it, I have the impression that you can almost see the interstellar material at times (I mean the gas that would be in and around the two stars, evidently predominantly flowing from the red giant to the white dwarf). It would be fascinating to be able to actually "see" the gas being captured into an accretion disk by the compact partner. I don't know which ranges of detection would be most helpful, but that video was from Chandra observations, which means X-Rays. I also get the impression from this mess that there are often jets of gas blown out of the dwarf companion (constantly?), which can relieve the situation before a nova occurs, but evidently sometimes too much builds up and it has gone to nova.

As to the second video, so, Jack Lemmon is kind of like a jet that often blows off some of the accretion in a steadier release, whereas Walter Matthau occasionally lets loose with a full-on nova, right?

R Aqr is a visual variable star for telescopic observers, but it's rarely visible to the naked eye as stated. It typically ranges between visual magnitudes 6 and 11.

John

[b][i] http://asterisk.apod.com/viewtopic.php?t=37257 [/i][/b]
[b][i] http://asterisk.apod.com/viewtopic.php?t=37275 [/i][/b]

[quote="Chris Peterson"][quote="madtom1999"]

Just wondering if there would be anything in the geological record for this
- would we have received enough gamma rays from the nova to leave a trace?[/quote]
We might have geological records of nearby [i]supernovas[/i],
but this system is much too far away, and the explosions far too weak to leave any trace.[/quote]
We might have geological records of recent nearby [i]supernova[/i] [url=https://en.wikipedia.org/wiki/Nuclear_fallout]fallout[/url]:

[list]. http://asterisk.apod.com/viewtopic.php?f=31&t=31332s#p198766[/list]

[quote="madtom1999"]Just wondering if there would be anything in the geological record for this - would we have received enough gamma rays from the nova to leave a trace?[/quote]
We might have geological records of nearby [i]supernovas[/i], but this system is much too far away, and the explosions far too weak to leave any trace. If this thing flared up again today, it would require sensitive instruments, probably in space, to even detect the resulting gamma rays.

[youtube]https://www.youtube.com/watch?v=k40iTA8cY4w[/youtube][youtube]https://www.youtube.com/watch?v=LDXSXkYoM5Y[/youtube]

[quote="NCTom"]Is this an oddly coupled binary system or are many/most binaries have such different companions? Would they both have been formed out of the same natal cloud or one "captured" the other?[/quote]
Binary stellar pairings come in all conceivable combinations, I think, so there isn't anything odd about this one. Almost all multiple stars were formed that way. Stellar capture would be the rare exception to the rule of how binaries form. It has recently been suggested that all stars are born in multi-star systems, with single star systems like ours being caused by the later disruption of widely spaced pairings.

Bruce

Is this an oddly coupled binary system or are many/most binaries have such different companions? Would they both have been formed out of the same natal cloud or one "captured" the other?

Also one of the first aesthetic images was [url=http://oldweb.aao.gov.au/images/captions/aat087.html]this one[/url] by the AAO.

[quote="madtom1999"]Just wondering if there would be anything in the geological record for this - would we have received enough gamma rays from the nova to leave a trace?[/quote]
There have been some historical records of "guest stars" corresponding to the location of R Aquarii in 1073 and 1074, see more [url=https://www.aanda.org/articles/aa/abs/2005/19/aa2455/aa2455.html]here[/url].

The nebula around R Aquarii is also catalogued as Ced 211. Interesting that the x-ray emission matches the position of the OIII jet, which in itself is also high excitation and hints of it can be seen in the [url=http://www.caelumobservatory.com/gallery/raquarii.shtml]original image[/url]. It would have been nice if this APOD was a mouseover with the x-ray overlay but there is one [url=http://chandra.harvard.edu/photo/2017/raqr/]here[/url]. Michael Sidonio has another image [url=http://www.pbase.com/strongmanmike2002/r_aquarii_]here[/url]. Another (confusing) example of a symbiotic nebula is the [url=http://www.chart32.de/index.php/component/k2/item/152]Southern Crab Nebula[/url].

Just wondering if there would be anything in the geological record for this - would we have received enough gamma rays from the nova to leave a trace?

[url=https://apod.nasa.gov/apod/ap170629.html][img]https://apod.nasa.gov/apod/calendar/S_170629.jpg[/img] [size=150]Symbiotic R Aquarii[/size][/url]

[b] Explanation: [/b] A long recognized naked-eye [url=https://www.aavso.org/vsots_raqr]variable star, R Aquarii[/url] is actually an interacting binary star system, two stars that seem to have a [url=http://chandra.harvard.edu/photo/2017/raqr/]close, symbiotic relationship[/url]. About 710 light years away, it consists of a cool red giant star and hot, dense white dwarf star in mutual orbit around their common center of mass. The binary system's visible light is dominated by the red giant, itself a [url=https://apod.nasa.gov/apod/ap070817.html]Mira-type long period[/url] variable star. But material in cool giant star's extended envelope is pulled by gravity onto the surface of the smaller, denser white dwarf, [url=https://apod.nasa.gov/apod/ap060726.html]eventually triggering[/url] a thermonuclear explosion and blasting material into space. Optical image data (red) shows the still expanding ring of debris originating from a blast that would have been seen in the early 1770s. [url=http://chandra.harvard.edu/photo/2017/raqr/animations.html]The evolution of[/url] less understood energetic events producing high energy emission in the R Aquarii system has been monitored since 2000 using Chandra X-ray Observatory data (blue). The composite field of view is less that a light-year across at the estimated distance of R Aquarii.

[b][table][tr][td=left][url=http://asterisk.apod.com/discuss_apod.php?date=170628]<< Previous APOD[/url][/td] [td=center][url=http://asterisk.apod.com/view_retro.php?date=0629]This Day in APOD[/url][/td] [td=right][url=http://asterisk.apod.com/discuss_apod.php?date=170630]Next APOD >>[/url][/td][/tr][/table][/b]