Determinations of the 12C/13C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi*

Harrison, T. E.; Marra, Rachel

doi:10.3847/1538-4357/aa7946

Cited by 8 publications

(10 citation statements)

References 25 publications

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“…Most designations of nonsolar 12 C/ 13 C are due to the appearance of 13 CO absorption where none is expected. Numerical values of 13 C/ 12 C for AE Aqr, SS Cyg and RU Peg are found in Harrison & Marra (2017). AE Aqr and SS Cyg have 12 C/ 13 C ∼ 4.…”

Section: Calculationsmentioning

confidence: 89%

“…Thus, using the average mass accretion onto its WD for U Gem from Dubus et al (2018) and the accreted mass needed for a TNR on a 1.25 M ⊙ ONeMg WD from Politano (1995), we can predict that U Gem will erupt as a ONeMg nova within 45,000 yrs. The high abundances of odd-numbered nuclear species above oxygen, which must come from high temperature H-capture on even numbered species, and the extreme deficits of carbon for EI Psc and QZ Ser (Harrison 2016;Harrison & Marra 2017) also makes them candidates for having ONeMg WDs. In fact, once the analysis is accurate enough to distinguish the abundances of these metals on many CVs, the number of ONeMg WDs relative to the CNO WDs can be determined directly.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…Stehle & Ritter (1999) found that for population II CVs, the abundance of the secondary's convective region was dominated by nova ejected material. Harrison & Marra (2017)'s preferred value of 12 C/ 13 C = 32 for RU Peg presents an interesting case. Its secondary mass is 0.96M ⊙ so that its present convective region is small, and its primary mass is 1.06M ⊙ , which limits the range of the initial mass of the secondary.…”

Section: Calculationsmentioning

confidence: 96%

“…Hamilton et al (2011) has examined the infrared spectrum for the CO absorption features in many pre-CVs and CVs and combined them with other studies. Harrison and colleagues (Harrison, Osborne, & Howell 2004Harrison & Marra 2017) have determined and listed the 12 CO/ 13 CO ratio from the K-band spectra.…”

Section: The Observational Evidence For Cvs With Non-solar Abundancesmentioning

confidence: 99%

“…Individually they are GW Lib (Szkody et al 2002), BW Scl (Gänsicke et al 2005), LL And (Howell et al 2002), WZ Sge , AL Com (Szkody et al 2003), SW UMa (Gänsicke et al 2005), HV Vir (Szkody et al 2002), WX Cet (Sion et al 2003), EG Cnc (Szkody et al 2002), BC UMa (Gänsicke et al 2005), VY Aqr (Sion et al 2003), EK Tra (Gänsicke et al 2001;Godon et al 2008), VW Hyi , EF Peg (Howell et al 2002), MV Lyr (Hoard et al 2004), DW UMa (Knigge et al 2000), WW Cet (Godon et al 2012), U Gem (Long et al 2006;Godon et al 2017), SS Aur (Sion et al 2004), RX And (Sion et al 2001), RU Peg (Sion et al 2004;Godon et al 2008), BY Cam (Mouchet et al 2003), BV Cen (Godon et al 2012), CH UMa (Godon et al 2012), EY Cyg (Godon et al 2008), EM Cyg (Godon et al 2012), SS Cyg (Godon et al 2012), UU Aql (Godon et al 2012), SS Aur (Godon & Sion 2021), TU Men (Godon & Sion 2021), and BZ UMa (Godon et al 2011). Infrared synthetic spectra of K-type secondaries have been compared to 41 CVs in a massive study by Harrison (2016); Harrison & Marra (2017). Harrison (2018) has also generated synthetic spectra with H-deficient stellar atmospheres and finds four systems that have significant hydrogen deficits.…”

Section: The Observational Evidence For Cvs With Non-solar Abundancesmentioning

confidence: 99%

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Nova-produced Common Envelope: Source of the Non-solar Abundances and an Additional Frictional Angular Momentum Loss in Cataclysmic Variables

Sparks,

Sion

2021

Preprint

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A substantial fraction of Cataclysmic Variables (CVs) reveals non-solar abundances. A comprehensive list of CVs which includes those that have been examined for these abundances is given. Three possible sources of these non-solar abundances on the secondary are accretion during the red giant common envelope phase, an Evolved Main Sequence secondary and nova-processed material. Use of the secondary's cross-section just on the escaping nova material to change the abundances of its convective region has been the killing objection for considering nova-processed material. The key element, ignored in other studies, is that a thermonuclear runaway on a white dwarf causes a strong propagating shock wave which not only ejects material, but also produces a large amount of non-ejected material which forms a common envelope. This nova-produced common envelope contains a large amount of non-solar material. We demonstrate that the secondary has the capacity and time to re-accrete enough of this material to acquire a significant non-solar convective region. This same envelope interacting with the binary will produce a Frictional Angular Momentum Loss which can be the Consequential Angular Momentum Loss needed for the average CV white dwarf mass, WD mass accretion rates, the period minimum, the orbital period distribution, and the space density of CVs problems. This interaction will decrease the orbital period which can cause the recently observed sudden period decreases across nova eruptions. A simple, rapid evolutionary model of the secondary that includes the swept-up nova-produced material and the increasing convective region is developed and applied to individual CVs.

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Section: Calculationsmentioning

confidence: 89%

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 96%

Section: The Observational Evidence For Cvs With Non-solar Abundancesmentioning

confidence: 99%

Section: The Observational Evidence For Cvs With Non-solar Abundancesmentioning

confidence: 99%

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Nova-produced Common Envelope: Source of the Non-solar Abundances and an Additional Frictional Angular Momentum Loss in Cataclysmic Variables

Sparks,

Sion

2021

Preprint

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The ESO SupJup Survey

González Picos,

Snellen,

de Regt

et al. 2024

A&A

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Young brown dwarfs exhibit atmospheric characteristics similar to those of super-Jupiters, providing a unique opportunity to study planetary atmospheres. Atmospheric retrievals of high-resolution spectra reveal detailed properties of these objects, with elemental and isotopic ratios offering insights into their formation history. The ESO SupJup Survey, utilising CRIRES$^+$ on the Very Large Telescope, aims to assess the role of as a formation tracer. We present observations of three young brown dwarfs: 2MASS J12003792-7845082, TWA 28, and 2MASS J08561384-1342242. Our goal is to constrain their chemical compositions, thermal profiles, surface gravities, spin rotations, and Cratio. We conducted atmospheric retrievals of CRIRES$^+$ K-band spectra, coupling the radiative transfer code petitRADTRANS with the Bayesian inference algorithm MultiNest The retrievals provide a detailed characterisation of the atmospheres of the three objects. We report the volume mixing ratios of the main molecular and atomic species: HF, Na, Ca, and Ti, including the novel detection of hydrogen fluoride (HF) in the atmosphere of a brown dwarf. We determine values of $ and $79^ $ in the atmospheres of TWA 28 and J0856, respectively, with strong significance ($>3 We also report tentative evidence ($ of in J1200, at $. Additionally, we detect at moderate significance in J0856 (3.3sigma ) and TWA 28 (2.1sigma ). The retrieved thermal profiles are consistent with hot atmospheres ($2300-2600$ K) with low surface gravities and slow spins, as expected for young objects. The measured carbon isotope ratios are consistent among the three objects and show no significant deviation from that of the local interstellar medium, suggesting a fragmentation-based formation mechanism similar to star formation. The tentative detection of in two objects of our sample highlights the potential of high-resolution spectroscopy to probe additional isotope ratios, such as O in the atmospheres of brown dwarfs and super-Jupiters.

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The C/N ratio from FUV spectroscopy as a constraint on evolution of the dwarf nova HS 0218 + 3229

Toloza

Gänsicke

Guzman-Rincon

et al. 2023

Monthly Notices of the Royal Astronomical Society

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White dwarfs that accrete from non-degenerate companions show anomalous carbon and nitrogen abundances in the photospheres of their stellar components have been postulated to be descendants of supersoft X-ray binaries. Measuring the carbon-to-nitrogen abundance ratio may provide constraints on their past evolution. We fit far-ultraviolet spectroscopy of the cataclysmic variable HS 0218+3229 taken with the Cosmic Origins Spectrograph using Markov Chain Monte Carlo methods, and found the carbon-to-nitrogen ratio is about one tenth of the Solar value ($\mbox{$\log \mathrm{[C/N]}$}=-0.56\pm 0.15$). We also provide estimates of the silicon and aluminium abundances, and upper limits for iron and oxygen. Using the parameters we derived for HS 0218+3229 we reconstruct its past. We calculated a grid of MESA models and implemented Gaussian process fits in order to determine its most likely initial binary configuration. We found that an initial mass of the donor of $M_{\rm donor;i}=0.90-0.98,\mbox{$\mathrm{M}_{\odot }$}$ and an initial orbital period of Porb; i = 2.88 d (Porb; i = 3.12 − 3.16 d) for an assumed initial white dwarf mass of $\mbox{$M_{\mathrm{WD}}$}_\mathrm{;i}=0.83\, \mbox{$\mathrm{M}_{\odot }$}$ ($\mbox{$M_{\mathrm{WD}}$}_{\rm ;i}=0.60\, \mbox{$\mathrm{M}_{\odot }$}$) can replicate the measured parameters. The low mass ratio, $M_{\rm donor;i} / \mbox{$M_{\mathrm{WD}}$}_{\rm ;i} =1.08-1.18\, (1.5-1.63)$, suggests that the system did not go through a phase of hydrogen-burning on the white dwarf’s surface. However, we can not exclude a phase of thermal timescale mass transfer in the past. We predict that HS 0218+3229 will evolve below the ≃ 76.2 ± 1 min period minimum for normal cataclysmic variables.

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Determinations of the ¹²C/¹³C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi^*

Cited by 8 publications

References 25 publications

Nova-produced Common Envelope: Source of the Non-solar Abundances and an Additional Frictional Angular Momentum Loss in Cataclysmic Variables

Nova-produced Common Envelope: Source of the Non-solar Abundances and an Additional Frictional Angular Momentum Loss in Cataclysmic Variables

The ESO SupJup Survey

The C/N ratio from FUV spectroscopy as a constraint on evolution of the dwarf nova HS 0218 + 3229

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