GK Cephei: rapid mass transfer between twin components in hierarchical triple system

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notFritzArgelander
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GK Cephei: rapid mass transfer between twin components in hierarchical triple system

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Post by notFritzArgelander »


The article:

https://phys.org/news/2021-06-reveal-ra ... nents.html

The paper abstract.....

https://academic.oup.com/mnras/article- ... m=fulltext
GK Cep is an eclipsing binary that contains two A-type components with an orbital period of 0.936 d. The high mass ratio and the contact or near-contact configuration make it a key target to understand binary evolution. However, the physical properties and evolutionary state are still unknown. Here we present the UV light curve obtained by using the lunar-based ultraviolet telescope (LUT) and several eclipse times obtained with the Sino-Thai 70-cm telescope and the 1.0-m telescope at Yunnan Observatories. Analysis of the LUT light curve suggests that GK Cep is a near-contact semidetached system where the slightly less massive component is the hotter one that is filling the critical Roche lobe. Meanwhile, a hotspot is found on the neck of the more massive but cooler component. By using all available times for the light minimum, it is detected that the O–C curve shows a cyclic oscillation while it undergoes an upward parabolic change. The increase of the orbital period, the high mass ratio, the semidetached configuration with a lobe-filling less massive component, and the presence of a hotspot on the more massive component all suggest that GK Cep is in a key evolutionary state just after the shortest-period evolutionary stage during the rapid mass transfer. The cyclic change in the O–C curve reveals that GK Cep contains a solar-type stellar companion in a triply hierarchical system that is in agreement with the spectroscopic result. The third body contributes about 2.6 per cent to the total light of the triple system.
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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helicon United States of America
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Re: GK Cephei: rapid mass transfer between twin components in hierarchical triple system

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Post by helicon »


Really cool that they used the LUT, lunar based telescope, to complete these observations of GK Cephei.
-Michael
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
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Re: GK Cephei: rapid mass transfer between twin components in hierarchical triple system

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Post by notFritzArgelander »


helicon wrote: Fri Jun 18, 2021 8:23 pm Really cool that they used the LUT, lunar based telescope, to complete these observations of GK Cephei.
Yes! I'm looking forward to more lunar observatories, especially on the radio quiet "other side".
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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