Nova shells

Cohen, J. G.; Rosenthal, Arnold J.

doi:10.1086/160990

Cited by 46 publications

(41 citation statements)

References 6 publications

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“…These two expansion velocities are found to be in excellent agreement for DQ Her and V533 Her, and within the uncertainties for FH Ser, whose v sp exp have been derived from spatiokinematic models. Remarkable discrepancies are found, however, for T Aur and V476 Cyg, whose spectroscopic observations are of low quality (Cohen, & Rosenthal 1983;Duerbeck 1987). An orientation of the major axis of these nova shells close to the line of sight cannot explain the much larger spectroscopic velocities of T Aur and V476 Cyg than the expansion velocities on the plane of the sky along the minor axis.…”

Section: Discussionmentioning

confidence: 91%

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Angular Expansion of Nova Shells

Santamaría

Guerrero

Ramos-Larios

et al. 2020

ApJ

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Nova shells can provide us with important information on their distance, their interactions with the circumstellar and interstellar media, and the evolution in morphology of the ejecta. We have obtained narrow-band images of a sample of five nova shells, namely DQ Her, FH Ser, T Aur, V476 Cyg, and V533 Her, with ages in the range from 50 to 130 years. These images have been compared with suitable available archival images to derive their angular expansion rates. We find that all the nova shells in our sample are still in the free expansion phase, which can be expected, as the mass of the ejecta is 7-45 times larger than the mass of the swept-up circumstellar medium. The nova shells will keep expanding freely for time periods up to a few hundred years, reducing their time dispersal into the interstellar medium

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Section: Discussionmentioning

confidence: 91%

“…Finally, the WD rotation may also feed the ejecta with Note-Distances were obtained from Gaia DR2 (Schaefer 2018). References for spectroscopic expansion velocities.-(1) Cohen, & Rosenthal (1983), (2) Duerbeck (1987), (3) Vaytet et al (2007), (4) Gill & O'Brien (2000).…”

Section: Introductionmentioning

confidence: 99%

Angular Expansion of Nova Shells

Santamaría

Guerrero

Ramos-Larios

et al. 2020

ApJ

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“…4) although at shorter wavelengths the emission Balmer jump mimics a steeper slope. Assuming an interstellar absorbtion A V = 0.3 mag (Cohen & Rosenthal 1983) and using the extinction law derived by Fitzpatrick (1999) we derive α λ ∼ 1.3. This is a lower value than predicted by integrating the radiation of a black body disk (Lynden-Bell 1969) with α λ = 2.3.…”

Section: The Spectrum and Line Identificationmentioning

confidence: 86%

The old nova CP Puppis: a carbon nova and asynchronous polar?

Bianchini

Saygac

Orio

et al. 2012

A&A

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Context. CP Pup (Nova Pup 1942) showed outburst and quiescent characteristics indicating a very massive white dwarf, yet the standard spectroscopic dynamical analysis assuming an accretion disk yields an extremely low value for the white dwarf mass. However, some physical parameters and the accretion geometry are still poorly known. Aims. The nova was spectroscopically monitored between 1988 and 1996. We analyzed the whole data set in order to re-determine the spectroscopic period and examine its stability. We also looked for chemical anomalies in the spectrum. Methods. We obtained the radial velocity curves for the hydrogen and helium lines from our last better quality 1996 run. The mean 1996 spectrum yields information on the chemical composition of the binary. We also searched the mean period using the multi-year data set. Results. From the radial velocities of our complete data set we derive the most probable mean spectroscopic period and tentatively suggest revised ephemeris. However, we demonstrate that the period is intrinsically unstable. We show that a standard accretion disk model does not explain all the spectroscopic features observed nor the variability of the spectroscopic period. We suggest that only interpreting the system as a slightly asynchronous polar would fit the data. The mean optical spectrum of CP Pup shows also an enhanced carbon abundance. Non solar abundances in the accreted material are unexpected and interesting, confirming that the nature of the secondaries of old novae should be studied more in detail. In fact, in CP Pup, as in other novae, the enhanced carbon is an important clue to the pre-outburst evolution, implying that the secondary was heavily polluted with carbon and helium during the common envelope phase of the pre-cataclysmic binary by a relatively massive primary that filled its Roche lobe during the third dredge up on the asymptotic giant branch.

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“…More recently, Harman & O'Brien (2003) obtained a new value of the distance, d = 0.97 ± 0.07 kpc, also from the expansion parallax method using HST imaging. Other, older, estimates are all between the above two estimates, i.e., d = 0.940 ± 0.155 kpc from various expansion par- allax methods (Malakpur 1975;Kohoutek 1981;Duerbeck 1981;Solf 1983;Cohen & Rosenthal 1983;Slavin et al 1994Slavin et al , 1995 or d = 0.835 ± 0.092 kpc from other techniques (Drechsel et al 1977). If we adopted the new distance estimate of d = 0.97 kpc (Harman & O'Brien 2003) and the extinction of E(B −V ) = 0.15 (Verbunt 1987), the distance modulus is (m − M) V = 5 log 970/10 + 3.1 × 0.15 = 10.4, which is perfectly consistent with the value in Equation (11).…”

Section: Hr Del 1967mentioning

confidence: 96%

THEUBVCOLOR EVOLUTION OF CLASSICAL NOVAE. I. NOVA-GIANT SEQUENCE IN THE COLOR-COLOR DIAGRAM

Hachisu

Kato

2014

ApJ

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We identified a general course of classical nova outbursts in the B − V versus U − B color-color diagram. It is reported that novae show spectra similar to those of A-F supergiants near optical light maximum. However, they do not follow the supergiant sequence in the color-color diagram, neither the blackbody nor the mainsequence sequence. Instead, we found that novae evolve along a new sequence in the pre-maximum and nearmaximum phases, which we call "the nova-giant sequence." This sequence is parallel to but ∆(U − B) ≈ −0.2 mag bluer than the supergiant sequence. This is because the mass of a nova envelope is much (∼ 10 −4 times) less than that of a normal supergiant. After optical maximum, its color quickly evolves back blueward along the same nova-giant sequence and reaches the point of free-free emission (B − V = −0.03, U − B = −0.97), which coincides with the intersection of the blackbody sequence and the nova-giant sequence, and remains there for a while. Then the color evolves leftward (blueward in B − V but almost constant in U − B), owing mainly to the development of strong emission lines. This is the general course of nova outbursts in the colorcolor diagram, which was deduced from eight well-observed novae in various speed classes. For a nova with unknown extinction, we can determine a reliable value of the color excess by matching the observed track of the target nova with this general course. This is a new and convenient method for obtaining the color excesses of classical novae. Using this method, we redetermined the color excesses of 20 well-observed novae. The obtained color excesses are in reasonable agreement with the previous results, which in turn support the idea of our general track of nova outbursts. Additionally, we estimated the absolute V magnitudes of about 30 novae using a method for time-stretching nova light curves to analyze the distance-reddening relations of the novae.

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Nova shells

Cited by 46 publications

References 6 publications

Angular Expansion of Nova Shells

Angular Expansion of Nova Shells

The old nova CP Puppis: a carbon nova and asynchronous polar?

THEUBVCOLOR EVOLUTION OF CLASSICAL NOVAE. I. NOVA-GIANT SEQUENCE IN THE COLOR-COLOR DIAGRAM

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