novae undersampled by observation

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notFritzArgelander
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novae undersampled by observation

#1

Post by notFritzArgelander »


Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: novae undersampled by observation

#2

Post by The Happy Parrot »


Interesting and strange that these novae cycle through different states over and over. I imagined these were "rare" events and it turns out they may all over the place.
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Graeme1858 Great Britain
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Re: novae undersampled by observation

#3

Post by Graeme1858 »


Interesting. I've not considered white dwarfs pulling hydrogen from a red dwarf binary companion. The scenario in my head was always a white dwarf pulling hydrogen from a red giant binary companion after going through a red giant phase itself. Either way the white dwarf will have had to have gone through its main sequence and red giant phases prior to becoming a white dwarf. Makes if difficult to see how a white dwarf could even exist as one of a binary pair to undergo nova behaviour near the beginning of a binary system's life as described.

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Re: novae undersampled by observation

#4

Post by notFritzArgelander »


Graeme1858 wrote: Wed Mar 25, 2020 12:39 am Interesting. I've not considered white dwarfs pulling hydrogen from a red dwarf binary companion. The scenario in my head was always a white dwarf pulling hydrogen from a red giant binary companion after going through a red giant phase itself. Either way the white dwarf will have had to have gone through its main sequence and red giant phases prior to becoming a white dwarf. Makes if difficult to see how a white dwarf could even exist as one of a binary pair to undergo nova behaviour near the beginning of a binary system's life as described.

Regards

Graeme
I read it a little differently, that the reference to "beginning" was to the "beginning of the binary as nova producing". I'll have another look....
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: novae undersampled by observation

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Post by Graeme1858 »


notFritzArgelander wrote: Wed Mar 25, 2020 12:45 am I read it a little differently, that the reference to "beginning" was to the "beginning of the binary as nova producing". I'll have another look....
I had better have another look too then! :D
______________________________________________
Celestron 9.25 f10 SCT, f6.3FR, CGX mount.
ASI1600MM Pro, ASI294MC Pro, ASI224MC
ZWO EFW, ZWO OAG, ASI220MM Mini.
APM 11x70 ED APO Binoculars.

https://www.averywayobservatory.co.uk/
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Re: novae undersampled by observation

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Post by Graeme1858 »


This bit:
Further, the study showed that almost all the novae we observe today occur near the beginning of a binary system's life as opposed to the end
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ASI1600MM Pro, ASI294MC Pro, ASI224MC
ZWO EFW, ZWO OAG, ASI220MM Mini.
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Re: novae undersampled by observation

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Post by notFritzArgelander »


Graeme1858 wrote: Wed Mar 25, 2020 12:53 am This bit:
Further, the study showed that almost all the novae we observe today occur near the beginning of a binary system's life as opposed to the end
You have uncovered my weakness as a proofreader. I tend to think some text reads as though it were correct. My understanding is that it SHOULD have read:
Further, the study showed that almost all the novae we observe today occur near the beginning of a binary system's life as a nova system as opposed to the end
Trust me. Only that makes sense. The literal text doesn't and is confusing.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: novae undersampled by observation

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Post by notFritzArgelander »


Unfortunately the paper is paywalled at Nature:

https://www.nature.com/articles/s41550-020-1062-y

But the abstract is available and reads, with light editing for legibility. (x,y,..) are reference footnotes.
The envelopes accreted by white dwarf stars from their hydrogen-rich companions(1) experience thermonuclear-powered runaways(2,3) observed as classical nova eruptions4,5 peaking at 10^5–10^6 solar luminosities(6,7,8,9). Virtually all nova progenitors—‘nova-like variables’—exhibit high mass transfer rates to their white dwarfs before and after an eruption(10). Surprisingly, 10–1,000 times lower mass transfer rate(11) binaries, exhibiting accretion-powered ‘dwarf nova’ outbursts(12), exist at identical orbital periods. Nova shells surrounding dwarf novae(13,14,15,16) demonstrate that at least some novae metamorphize into dwarf novae(17,18), though the mechanisms and timescales governing mass transfer rate variations are poorly understood. Here, we report simulations of the multi-Gyr evolution of novae modelling every eruption’s thermonuclear runaway, mass and angular momentum losses, feedback due to irradiation and variable mass transfer rate, and orbital size and period changes. These feedback-dominated simulations reproduce the observed range of mass transfer rates at a given orbital period, with large and cyclic kyr–Myr timescale changes. They also demonstrate Myr-long deep hibernation (complete stoppage of mass transfer), but only in short-period binaries; that initially different binaries converge to become nearly identical systems; low-mass-transfer-rate dwarf novae occasionally generate novae; and that the masses of white dwarfs decrease monotonically, but only slightly while their red dwarf companions are consumed.
This is consistent with my rewrite of the problem sentence in the article and not with the article as written. Thanks for pointing out the problematic sentence!
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: novae undersampled by observation

#9

Post by Graeme1858 »


notFritzArgelander wrote: Wed Mar 25, 2020 2:39 am You have uncovered my weakness as a proofreader.

Sorry! :) I won't tell anyone!

notFritzArgelander wrote: Wed Mar 25, 2020 2:39 am
Further, the study showed that almost all the novae we observe today occur near the beginning of a binary system's life as a nova system as opposed to the end

Trust me. Only that makes sense. The literal text doesn't and is confusing.

Agreed. And It doesn't really sound like much of a new discovery!

Regards

Graeme
______________________________________________
Celestron 9.25 f10 SCT, f6.3FR, CGX mount.
ASI1600MM Pro, ASI294MC Pro, ASI224MC
ZWO EFW, ZWO OAG, ASI220MM Mini.
APM 11x70 ED APO Binoculars.

https://www.averywayobservatory.co.uk/
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Re: novae undersampled by observation

#10

Post by notFritzArgelander »


Graeme1858 wrote: Wed Mar 25, 2020 7:45 am
notFritzArgelander wrote: Wed Mar 25, 2020 2:39 am You have uncovered my weakness as a proofreader.

Sorry! :) I won't tell anyone!

notFritzArgelander wrote: Wed Mar 25, 2020 2:39 am
Further, the study showed that almost all the novae we observe today occur near the beginning of a binary system's life as a nova system as opposed to the end

Trust me. Only that makes sense. The literal text doesn't and is confusing.

Agreed. And It doesn't really sound like much of a new discovery!

Regards

Graeme
What’s new is that simulations have linked the stages of a nova system together coherently. The observations have indicated that they must be so.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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