Nova Persei

Pickering, William H.

doi:10.1086/140829

Cited by 2 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based in part on observations made at Observatoire de Chelles, 77500 Chelles, France evolves from A7III to F8III (Gillet & Crowe 1988). RR Lyr variability was discovered by the Scottish astronomer Williamina Fleming at Harvard in 1901 (Pickering et al 1901). The pulsation cycle occurs on approximately 0.5668 d or, equivalently, 13.6 h. Furthermore, the light curve also presents light modulations with a variable period around 39 d. These amplitude and phase modulations are known as the Blazhko effect.…”

Section: Introductionmentioning

confidence: 99%

Dynamical structure of the pulsating atmosphere of RR Lyrae

Gillet¹,

Mauclaire²,

Lemoult³

et al. 2019

A&A

View full text Add to dashboard Cite

Context. RRab stars are large amplitude pulsating stars in which the pulsation wave is a progressive wave. Consequently, strong shocks, stratification effects, and phase lag may exist between the variations associated with line profiles formed in different parts of the atmosphere, including the shock wake. The pulsation is associated with a large extension of the expanding atmosphere, and strong infalling motions are expected. Aims. The objective of this study is to provide a general overview of the dynamical structure of the atmosphere occurring over a typical pulsation cycle. Methods. We report new high-resolution observations with suitable time resolution of Hα and sodium lines in the brightest RR Lyrae star of the sky: RR Lyr (HD 182989). A detailed analysis of line profile variations over the whole pulsation cycle is performed to understand the dynamical structure of the atmosphere. Results. The main shock wave appears when it exits from the photosphere at ϕ 0.89, i.e., when the main Hα emission is observed. Whereas the acceleration phase of the shock is not observed, a significant deceleration of the shock front velocity is clearly present. The radiative stage of the shock wave is short: 4% of the pulsation period (0.892 < ϕ < 0.929). A Mach number M > 10 is required to get such a radiative shock. The sodium layer reaches its maximum expansion well before that of Hα (∆ϕ = 0.135). Thus, a rarefaction wave is induced between the Hα and sodium layers. A strong atmospheric compression occurring around ϕ = 0.36, which produces the third Hα emission, takes place in the highest part of the atmosphere. The region located lower in the atmosphere where the sodium line is formed is not involved. The amplification of gas turbulence seems mainly due to strong shock waves propagating in the atmosphere rather than to the global compression of the atmosphere caused by the pulsation. It has not yet been clearly established whether the microturbulence velocity increases or decreases with height in the atmosphere. Furthermore, it seems very probable that an interstellar component is visible within the sodium profile.

show abstract

Section: Introductionmentioning

confidence: 99%

Dynamical structure of the pulsating atmosphere of RR Lyrae

Gillet¹,

Mauclaire²,

Lemoult³

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

“…Most of the following is based on McLaughlin (1943). It is interesting to note that the paper makes it a point to mention that the velocity displacements of the absorption lines and widths of the emission lines are due to the Doppler effect in an expanding shell of gas as was suggested by Pickering (1901). Although this is something we take for granted today, it was not obvious then and shows how our knowledge has gradually built up over time from the sincere efforts of many scientists.…”

Section: Existing Astrophysical Model For Novaementioning

confidence: 82%

“…It is also worth noting that from early observations of novae it was obvious to astronomers that classical, recurrent and dwarf novae consisted of the same basic components. It was suggested that the nature of the observed spectra of nova outbursts can be explained if they arose in an expanding sphere of hot gases that cooled as it expanded so that the spectral lines appeared in absorption or emission and were broadened (Pickering, 1901). From the observed character of the light curve, it was also suggested that the nova outburst whatever its cause led to a major ejection of matter which was followed by continuous ejection in the form of winds (e.g.…”

Section: Background On Novaementioning

confidence: 99%

Novae II. Model, multi-band outburst, bipolar ejecta, accretion disk, relativistic electrons, etc

Kantharia¹

2017

Preprint

View full text Add to dashboard Cite

Nova Persei

Cited by 2 publications

References 0 publications

Dynamical structure of the pulsating atmosphere of RR Lyrae

Dynamical structure of the pulsating atmosphere of RR Lyrae

Novae II. Model, multi-band outburst, bipolar ejecta, accretion disk, relativistic electrons, etc

Contact Info

Product

Resources

About