Organization of the flame in tank furnaces

Kukarkin, A. I.; Kocho, V. S.

doi:10.1007/bf00669871

Cited by 2 publications

(7 citation statements)

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“…To establish this, and considering the time spent by a star on the HB as RR Lyrae, they estimated that the time baseline needed to be extended yet another 30 years. Kukarkin & Kukarkina (1971) extended the period changes analysis for 51 stars Storm et al (1991); BRO (calculated in this work from data by Brocato et al 1996); KAL (calculated from data by Kaluzny et al 1999) 1952 and 1958-1968. They did not publish their observations but listed series of times of maximum light for all the stars in their sample and offered O − C diagrams.…”

Section: Previous Studies Of Rr Lyrae Secular Period Variations In M5mentioning

confidence: 69%

“…years band notes Bailey (1917) 1889-1912 pg 1 Shapley (1927) 1917 pg 2 Oosterhoff (1941) 1932-35 pg 3 Coutts & Sawyer-Hogg (1969) 1936-66 pg Szeidl et al (2011) 1952-1963 pg Szeidl et al (2011) 1971-1993 pg Kukarkin & Kukarkina (1971) 4 Cohen & Gordon (1987) 1986 B, i Storm et al (1991) 1987 CCD V Cohen & Matthews (1992) 1989 CCD V Brocato et al (1996) 1989 CCD V Reid (1996) 1991-92 CCD V Kaluzny et al (1999) 1997 CCD V Present work 2012-14 CCD V…”

Section: Authorsmentioning

confidence: 99%

“…1. Times of maximum light were calculated by Kukarkin & Kukarkina (1971), 2: Light curves and times of maximum in Coutts & Sawyer-Hogg (1969) and Coutts (1971). 3: Times of maximum in Coutts & Sawyer-Hogg (1969).…”

Section: Authorsmentioning

confidence: 99%

“…Secular period changes in the RR Lyrae stars (RRLs) of NGC 5904 (M5, or C1516+022 in the IAU nomenclature) (α = 15 h 18 m 33.2 s , δ = +02 • 04 ′ 51.7 ′′ , J2000; l = 3.85 • , b = +46.80 • ), have been measured since the pioneering work of Oosterhoff (1941), and in the following seven decades several authors have tackled the problem of estimating the period change rates in pursuit of measurable indications of the stellar evolution on the horizontal branch (HB) accross the instability strip (IS) (Coutts & Sawyer-Hogg 1969, Kukarkin & Kukarkina 1971, Storm et al 1991, Reid 1996, Szeidl et al 2011. Photometric studies of M5 are numerous, as are timeseries data of its variable stars since 1889 (Bailey 1917), leading to a wealth of resources available for the study of secular period variations.…”

Section: Introductionmentioning

confidence: 99%

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A New Overview of Secular Period Changes of RR Lyrae stars inM5

Ferro,

Ahumada,

Kains

et al. 2016

Preprint

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Secular period variations, β = Ṗ , in 76 RR Lyrae stars in the globular cluster M5 are analysed using our most recent CCD V photometry and the historical photometric database available in the literature since 1889. This provides a time baseline of up to 118 years for these variables. The analysis was performed using two independent approaches: first, the classical O − C behaviour of the time of maximum light, and second, via a grid (P, β), where the solution producing the minimum scatter in the phased light curve is chosen. The results of the two methods agree satisfactorily. This allowed a new interpretation of the nature of the period changes in many RR Lyrae stars in M5. It is found that in 96% of the stars studied no irregular or stochastic variations need to be claimed, but that 66% of the population shows steady period increases or decreases, and that 34% of the periods seem to have been stable over the last century.The lack of systematic positive or negative period variations in RR Lyrae stars in other globular clusters is addressed, and the paradigm of period changes being a consequence of stellar evolution is discussed in terms of chemical variations near the stellar core and of multiple stellar populations. In M5 we found a small positive average value of β and a small surplus of RRab stars with a period increase. Nevertheless, in M5 we have been able to isolate a group of likely evolved stars that systematically show positive, and in some cases large, period change rates.

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Section: Previous Studies Of Rr Lyrae Secular Period Variations In M5mentioning

confidence: 69%

Section: Authorsmentioning

confidence: 99%

Section: Authorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A New Overview of Secular Period Changes of RR Lyrae stars inM5

Ferro,

Ahumada,

Kains

et al. 2016

Preprint

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“…The prototype of the β Cephei class of pulsating stars, β Cep (HD 205021, spectral type B2III, V = 3.2), is a massive (M = 12 ± 1 M , Donati et al 2001) pulsating star with a period of approximatively P = 0.1905 days (Kukarkin et al 1971). The radial-velocity variations of this star were first detected by Frost (1902).…”

Section: Introductionmentioning

confidence: 99%

An investigation of the close environment ofβCephei with the VEGA/CHARA interferometer

Nardetto¹,

Mourard²,

Tallon–Bosc

et al. 2010

A&A

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Context. High-precision interferometric measurements of pulsating stars help to characterize their close environment. In 1974, a close companion was discovered around the pulsating star β Cep using the speckle interferometry technique, and features at the limit of resolution (20 milli-arcsec or mas) of the instrument were mentioned that may be due to circumstellar material. β Cep has a magnetic field that might be responsible for a spherical shell or ring-like structure around the star as described by the MHD models. Aims. Using the visible recombiner VEGA installed on the CHARA long-baseline interferometer at Mt. Wilson, we aim to determine the angular diameter of β Cep and resolve its close environment with a spatial resolution up to 1 mas level. Methods. Medium spectral resolution (R = 6000) observations of β Cep were secured with the VEGA instrument over the years 2008 and 2009. These observations were performed with the S1S2 (30 m) and W1W2 (100 m) baselines of the array. Results. We investigated several models to reproduce our observations. A large-scale structure of a few mas is clearly detected around the star with a typical flux relative contribution of 0.23 ± 0.02. Our best model is a co-rotational geometrical thin ring around the star as predicted by magnetically-confined wind shock models. The ring inner diameter is 8.2 ± 0.8 mas and the width is 0.6 ± 0.7 mas. The orientation of the rotation axis on the plane of the sky is PA = 60 ± 1 deg, while the best fit of the mean angular diameter of β Cep gives Φ UD [V] = 0.22 ± 0.05 mas. Our data are compatible with the predicted position of the close companion of β Cep. Conclusions. These results bring additional constraints on the fundamental parameters and on the future MHD and asteroseismological models of the star.

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Organization of the flame in tank furnaces

Cited by 2 publications

References 0 publications

A New Overview of Secular Period Changes of RR Lyrae stars inM5

A New Overview of Secular Period Changes of RR Lyrae stars inM5

An investigation of the close environment ofβCephei with the VEGA/CHARA interferometer

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