Cosmological Implications of the Second Parameter of Type Ia Supernovae by Podsiadlowski, P, Mazzali, P, Lesaffre, P, Wolf, C, Forster, F

“…Here we show that this metallicity effect can be substantially larger than has been estimated previously, when the neutronisation in the immediate pre-explosion phase in the CO white dwarf is taken into account, and quantitatively assess the importance of metallicity evolution for determining cosmological parameters. …”

Disk Detective: Discovery of new circumstellar disk candidates through citizen science by Kuchner, M, Silverberg, S, Bans, A, Bhattacharjee, S, Kenyon, S, Debes, J, Currie, T, García, L, Jung, D, Lintott, C, McElwain, M, Padgett, D, Rebull, L, Wisniewski, J, Nesvold, E, Schawinski, K, Thaller, M, Grady, C, Biggs, J, Bosch, M, C̆ernohous, T, Luca, H, Hyogo, M, Wah, L, Piipuu, A, Piñeiro, F

“…One of these systems appears to contain the first debris disk discovered around a star with a white dwarf companion: HD 74389. We also report four newly discovered classical Be stars (HD 6612, HD 7406, HD 164137, and HD 218546) and a new detection of 22 μm excess around the previously known debris disk host star HD 22128.…”

NON-THERMAL EMISSION FROM CATACLYSMIC VARIABLES: IMPLICATIONS ON ASTROPARTICLE PHYSICS by Vojtech Šimon

“…The propeller effect or a shock in the case of the magnetized white dwarf (WD) can lead to a strong acceleration of the particles that produce gamma-ray emission via pi0 decay; even Cherenkov radiation is possible. …”
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Connecting RS OPh to [some] Type Ia Supernovae by Patat, F, Chugai, N, Podsiadlowski, P, Mason, E, Melo, C, Pasquini, L

“…Aims: Recurrent nova systems like RS Oph have been proposed as a possible channel to Type Ia Supernova explosions, based on the high mass of the accreting white dwarf. Additional support to this hypothesis has been recently provided by the detection of circumstellar material around SN2006X and SN2007le, showing a structure compatible with that expected for recurrent nova outbursts.In this paper we investigate the circumstellar environment of RS Oph and its structure, with the aim of establishing a firmer and independent link between this class of objects and Type Ia SN progenitors. …”

The single degenerate channel for the progenitors of type Ia supernovae by Han, Z, Podsiadlowski, P

“…We have carried out a detailed study of one of the most popular evolutionary channels for the production of Type Ia supernova (SN Ia) progenitors, the semi-degenerate channel (CO+MS), where a carbon/oxygen (CO) white dwarf (WD) accretes matter from an unevolved or slightly evolved non-degenerate star until it reaches the Chandrasekhar mass limit. …”

An emission-state-switching radio transient with a 54-minute period by Caleb, M, Lenc, E, Kaplan, DL, Murphy, T, Men, YP, Shannon, RM, Ferrario, L, Rajwade, KM, Clarke, TE, Giacintucci, S, Hurley-Walker, N, Hyman, SD, Lower, ME, McSweeney, S, Ravi, V, Barr, ED, Buchner, S, Flynn, CML, Hessels, JWT, Kramer, M, Pritchard, J, Stappers, BW

“…Although magnetic white dwarfs and magnetars, either isolated or in binary systems, have been invoked to explain these objects, a consensus has not emerged. …”

Theoretical Light-curve Models of the Symbiotic Nova CN Cha—Optical Flat Peak for 3 Yr by Mariko Kato, Izumi Hachisu

“…We present theoretical light curves for CN Cha, based on hydrostatic approximation, and estimate the white-dwarf (WD) mass to be ∼0.6 M _☉ for a low metal abundance of Z = 0.004. …”
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The High-resolution Soft X-Ray Spectrum of Nova Delphini 2013 by Johon Milla, Frits Paerels

“…We observe the photospheric emission spectrum of the hot white dwarf, which exhibits a rich absorption line spectrum from an atmosphere of effective temperature likely near T _eff ∼ 640,000 K, and complex chemical abundances. …”
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Stark Broadening of N VI Spectral Lines by Milan S. Dimitrijević, Magdalena D. Christova, Sylvie Sahal-Bréchot

“…An example of the importance of Stark broadening in comparison with thermal Doppler broadening in atmospheres of spectral class DO white dwarfs is also presented. The obtained results are of interest particularly for white dwarf atmospheres modelling and analysis and synthesis of their spectra as well as for laser driven plasma in proton-boron fusion investigations.…”
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Planetary Engulfment Prognosis within the ρ CrB System by Stephen R. Kane

“…Exoplanets have been detected around stars at various stages of their lives, ranging from young stars emerging from formation to the latter stages of evolution, including white dwarfs and neutron stars. Post-main-sequence stellar evolution can result in dramatic, and occasionally traumatic, alterations to the planetary system architecture, such as tidal disruption of planets and engulfment by the host star. …”
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TESS Observations of Outbursts on Polars—Superflares by Qishan Wang, Xiaohui Fang, Shengbang Qian

“…Among them, two flares are followed by a brightness enhancement, which may suggest an accretion burst on the white dwarf caused by a coronal mass ejection. A completeness analysis of the detections demonstrates that the flare activities on the low-mass red dwarfs of polars are very similar to those on M dwarfs, which indicates that the highly magnetic fields of the white dwarfs have no significant effect on the magnetic activities on polars. …”
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Period Changes of W UMa Type Contact Binary SS ARIETIS by Chun-Hwey Kim, Wonyong Han, Jae Hyuk Yoon, Il-Seong Nha

“…In the earlier case, the third body has a mass of 1.3Msolar if exists, in the form of a white dwarf or a binary system. It seems that the system velocities from the spectroscopic observations supports this interpretation. …”
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A common-envelope wind model for Type Ia supernovae – I. Binary evolution and birth rate by Meng, X, Podsiadlowski, P

“…Here, we propose a new version of the SD model in which a common envelope (CE) is assumed to form when the mass-transfer rate between a carbon-oxygen white dwarf (CO WD) and its companion exceeds a critical accretion rate. …”

Cataclysmic Variables with Evolved Secondaries and the Progenitors of AM CVn Stars by Podsiadlowski, P, Han, Z, Rappaport, S

“…In these sequences, we used 3 masses for the white dwarf (0.6, 0.8, 1.0 Msun) and seven masses for the donor star in the range of 0.6-1.4 Msun. …”

Hot subdwarf binaries - Masses and nature of their heavy compact companions by Geier, S, Heber, U, Edelmann, H, Kupfer, T, Napiwotzki, R, Podsiadlowski, P

“…While most hot subdwarf binaries have white-dwarf or late-type main sequence companions, as predicted by binary evolution models, at least 5% of the observed subdwarfs must have very massive companions: unusually heavy white dwarfs, neutron stars and, in some cases, even black holes. …”

Don’t blink: constraining the circumstellar environment of the interacting type Ia supernova 2015cp by Harris, C, Nugent, P, Horesh, A, Bright, J, Fender, R, Graham, M, Maguire, K, Smith, M, Butler, N, Valenti, S, Filippenko, A, Fox, O, Goobar, A, Kelly, P, Shen, K

“…Despite their cosmological utility, the progenitors of Type Ia supernovae (SNe Ia) are still unknown, with many efforts focused on whether accretion from a nondegenerate companion can grow a carbon–oxygen white dwarf to near the Chandrasekhar mass. The association of SNe Ia resembling SN 1991T ("91T-like") with circumstellar interaction may be evidence for this "single-degenerate" channel. …”

Modelling the circumstellar medium in RS Ophiuchi and its link to Type Ia supernovae by Booth, RA, Mohamed, S, Podsiadlowski, P

“…We find that the quiescent mass transfer produces a dense, equatorial outflow, i.e. concentrated towards the binary orbital plane, and an accretion disc forms around the white dwarf. The interaction of a spherical nova outburst with these aspherical circumstellar structures produces a bipolar outflow, similar to that seen in Hubble Space Telescope imaging of the 2006 outburst. …”

Two-Color VR CCD Photometry of the Intermediate Polar 1RXS J062518.2+733433 by Yonggi Kim, Ivan L. Andronov, Sung Su Park, Lidia L. Chinarova, Alexey V. Baklanov, Young-Beom Jeon

“…This new phenomenon is explained by the changing viewing conditions of the accreting magnetic white dwarf, and should be checked in further observations this star and for other intermediate polars. …”
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POLAR project: a numerical study to optimize the target design by C Busschaert, É Falize, B Loupias, C Michaut, A Ravasio, A Pelka, R Yurchak, M Koenig

“…At the astrophysical scale, the system we consider is a column of infalling plasma collimated by a magnetic field onto the surface of a white dwarf. As matter hits the surface with supersonic velocity, a shock forms at the basis of the column and propagates upstream. …”
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Prospects of Constraining the Dense Matter Equation of State from Timing Analysis of Pulsars in Double Neutron Star Binaries: The Cases of PSR J0737 ‒ 3039A and PSR J1757 ‒ 1854... by Manjari Bagchi

“…Pulsars in double neutron star binaries are the best for this purpose as short orbits and moderately high eccentricities make the Lense-Thirring effect substantial, whereas tidal effects are negligible (unlike pulsars with main sequence or white-dwarf binaries). The most promising pulsars are PSR J0737 − 3039A and PSR J1757 − 1854. …”
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