scholarly journals High Time Resolution Photometry of Red Dwarf Flare Stars I. A Search For Fine Structures on the Optical Light Curves of Flares

1989 ◽  
Vol 104 (2) ◽  
pp. 95-97
Author(s):  
G.M. Beskin ◽  
S.N. Mitronova ◽  
S.I. Neizvestnyj ◽  
V.L. Plakhotnichenko ◽  
L.A. Pustil'nik ◽  
...  
Keyword(s):  
Detailed Analysis ◽  
Time Scales ◽  
Time Resolution ◽  
Light Curves ◽  
High Time ◽  
Special Astrophysical Observatory ◽  
High Time Resolution ◽  
Fine Structures ◽  
Flare Stars

AbstractA detailed analysis of 73 flares on UV Cet type stars observed at the 6 m telescope of the Special Astrophysical Observatory with 3x10–7 s time resolution shows no fine structures on flare light curves with time scales from 10–6 to 10–1 s.

scholarly journals High Time Resolution Photometry of Red Dwarf Flare Stars III. The Most Rapid and Faintest Observed Stellar Flares; their Physics and Statistics

1989 ◽  
Vol 104 (2) ◽  
pp. 103-105
Author(s):  
G.M. Beskin ◽  
S.I. Neizvestnyj ◽  
V.L. Plakhotnichenko ◽  
L.A. Pustil'nik ◽  
V.F. Shvartsman ◽  
...  
Keyword(s):  
Time Scales ◽  
Time Resolution ◽  
Total Duration ◽  
High Time ◽  
Energy Output ◽  
Total Power ◽  
High Time Resolution ◽  
Upper Limit ◽  
Stellar Flares ◽  
Flare Stars

AbstractHigh time resolution monitoring of the UV Cet type flare stars has enabled as to detect flares with total duration of a few seconds and with energy output comparable to solar subflares. We find that the time scales of decay for such flares correspond to recombination times of optically thin gas or to cooling times of optically thick gas heated in flares. Therefore, faster flares cannot be detected individually but their accumulated effect may be one source of brightness fluctuations of the “quiet” star. The upper limit for the total power of such microflares does not exceed the time-averaged power of individually detected flares.

scholarly journals High Time-Resolution Astronomy on the 10-m SALT

2011 ◽  
Vol 7 (S285) ◽  
pp. 99-102
Author(s):  
Barry Welsh ◽  
David Anderson ◽  
Jason McPhate ◽  
John Vallerga ◽  
Oswald H. W. Siegmund ◽  
...  
Keyword(s):  
Time Scales ◽  
Time Resolution ◽  
Detector System ◽  
High Time ◽  
High Time Resolution ◽  
Large Telescope ◽  
Visible Imaging ◽  
Visible Wavelengths ◽  
General User ◽  
Opening Up

AbstractWe present a brief description of the Berkeley Visible Imaging Tube (BVIT) detector system, which is a user instrument on the 10-m Southern African Large Telescope (SALT), and include some preliminary observational results gained in mid-2011. The data show that BVIT is capable of revealing emission features occurring on time-scales of < 0.1 sec, thus opening up for the general user a window of high time-resolution astronomy at visible wavelengths.

scholarly journals Statistics of flares observed for UV Ceti type stars YZ CMi, AD Leo, and EV Lac at the Okayama Observatory

1990 ◽  
Vol 137 ◽  
pp. 43-47
Author(s):  
K. Ishida
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Ceti Type ◽  
Flare Stars ◽  
Ev Lac

Photoelectric monitoring of flare stars YZ CMi, AD Leo, and EV Lac has been done at the Okayama Observatory since early 1970s. This is a simultaneous UBV observations with a high time resolution. Some statistics of the flares of the UV Ceti type stars are presented.

scholarly journals Period Changes in the SX Phoenicis Star CY Aquarii

1993 ◽  
Vol 139 ◽  
pp. 428-428
Author(s):  
Michael D. Joner ◽  
John M. Powell
Keyword(s):  
Time Resolution ◽  
Light Curves ◽  
High Time ◽  
High Time Resolution ◽  
Present Evidence ◽  
Brigham Young University ◽  
Maximum Light

AbstractCY Aquarii is a Population II dwarf Cepheid that has been observed on a regular basis since 1930. We present evidence from unpublished times of maximum light from Brigham Young University observations secured in the mid-1970s to the present that indicate that the period of CY Aqr has changed in a discontinuous manner. Furthermore, we find that the period has changed significantly since the epoch of the last published investigation (1988). Finally, contrary to some past claims, examination of our high time resolution light curves yields no indication of multi-periodic pulsation in CY Aqr.

scholarly journals High Time Resolution Photometry of Red Dwarf Flare Stars II. The Shortest Flare Rise Time

1989 ◽  
Vol 104 (2) ◽  
pp. 99-101
Author(s):  
G.M. Beskin ◽  
V.L. Plakhotnichenko ◽  
L.A. Pustil'nik ◽  
V.F. Shvartsman ◽  
R.E. Gershberg
Keyword(s):  
Time Resolution ◽  
Rise Time ◽  
Total Duration ◽  
High Time ◽  
High Time Resolution ◽  
Gas Dynamic ◽  
Flare Stars ◽  
Flare Model

AbstractWe have studied the initial phases of 65 optical flares on UV Cet type stars with a time resolution of 3x10–7 s. Ninety per cent of these flares have rapid brightenings shorter than 10 s and several are shorter than 1 s. We detected on UV Cet the shortest flare observed to date with a total duration of 1.7 s and a rise time of 0.3 s. The shortest flare rise times on the observed stars fit the predictions of the gas-dynamic flare model by Katsova et al. (1981) and Katsova and Livshits 1986).

scholarly journals Two-colour observations of spikes and flares by high time resolution

1990 ◽  
Vol 137 ◽  
pp. 33-34
Author(s):  
V.P. Zalinian ◽  
A.A. Karapetian ◽  
H.M. Tovmassian
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Long Duration ◽  
Flare Stars ◽  
Ev Lac

Observations of flare stars with high time resolution permit to register spiky type flares and also to study in detail bright curves of flares. In Byurakan observatory observations of EV Lac have been made with 0.1 s time resolution simultaneouslyin two filters “U” and “B” [1-3]. These observations permited to detect flares of a burst type (Fig.1) and also to reveil multipeak structure of long duration flares. It is necessary to stress that simultaneous observations in two colours increas appresiably the thrustworthiness of the registered spiky flares.

scholarly journals Flare Stars in Stellar Aggregates

1977 ◽  
Vol 42 ◽  
pp. 106-119
Author(s):  
L.V. Mirzoyan
Keyword(s):  
Time Resolution ◽  
Physical Nature ◽  
High Time ◽  
Optical Observations ◽  
Evolutionary Significance ◽  
High Time Resolution ◽  
Radio Observations ◽  
Stellar Flares ◽  
Flare Stars

After the report on flare stars presented by Ambartsumian and the author (1971) at the last Bamberg Colloquium, some success has been achieved in the study of these interesting objects.Optical observations of stellar flares with high time-resolution undoubtedly proved the explosive character of this phenomenon and the non-thermal nature of the radiation that appears at least at the beginning of the flare. Parallel optical and radio observations of flares in stellar aggregates complicated the interpretation and showed how far we are from an understanding of the physical nature of this phenomenon. Finally, new optical observations of stellar flares in aggregates of different age confirmed the evolutionary significance of this stage in the life of a star and led to the study of certain regularities in the evolution of flare stars.

scholarly journals Investigating radiation belt losses though numerical modelling of precipitating fluxes

2004 ◽  
Vol 22 (10) ◽  
pp. 3657-3667 ◽  
Author(s):  
C. J. Rodger ◽  
D. Nunn ◽  
M. A. Clilverd
Keyword(s):  
Numerical Modelling ◽  
Electron Energy ◽  
Time Scales ◽  
Time Resolution ◽  
Radiation Belt ◽  
Electron Precipitation ◽  
High Time ◽  
High Time Resolution ◽  
Perturbation Size ◽  
Over Time

Abstract. It has been suggested that whistler-induced electron precipitation (WEP) may be the most significant inner radiation belt loss process for some electron energy ranges. One area of uncertainty lies in identifying a typical estimate of the precipitating fluxes from the examples given in the literature to date. Here we aim to solve this difficulty through modelling satellite and ground-based observations of onset and decay of the precipitation and its effects in the ionosphere by examining WEP-produced Trimpi perturbations in subionospheric VLF transmissions. In this study we find that typical Trimpi are well described by the effects of WEP spectra derived from the AE-5 inner radiation belt model for typical precipitating energy fluxes. This confirms the validity of the radiation belt lifetimes determined in previous studies using these flux parameters. We find that the large variation in observed Trimpi perturbation size occurring over time scales of minutes to hours is primarily due to differing precipitation flux levels rather than changing WEP spectra. Finally, we show that high-time resolution measurements during the onset of Trimpi perturbations should provide a useful signature for discriminating WEP Trimpi from non-WEP Trimpi, due to the pulsed nature of the WEP arrival.

Solar Corona Investigation by the Coronal Line Photometer at Lomnický Peak

1994 ◽  
Vol 144 ◽  
pp. 431-434
Author(s):  
M. Minarovjech ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
Time Resolution ◽  
Active Regions ◽  
High Time ◽  
High Time Resolution ◽  
List Type ◽  
Type Number ◽  
Coronal Line ◽  
Global Cycle

AbstractThis paper deals with a possibility to use the ground-based method of observation in order to solve basic problems connected with the solar corona research. Namely:1.heating of the solar corona2.course of the global cycle in the corona3.rotation of the solar corona and development of active regions.There is stressed a possibility of high-time resolution of the coronal line photometer at Lomnický Peak coronal station, and use of the latter to obtain crucial observations.

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