19 research outputs found
Dwarf Nova-like Outburst of Short Period Intermediate Polar HT Camelopardalis
We report the first time-series observations of the short outburst of the
proposed intermediate polar HT Cam (=RX J0757.0+6306). On 2001 December 29, we
detected the object was undergoing a bright outburst at the magnitude of
. Following this detection, we started international joint
observations through VSNET. The light curve showed a gradual decline for the
first 0.5 d. Following this short plateau phase, the rate of decline
dramatically increased to more than 4 mag d. Within 1.5 d from the
outburst detection, the object almost declined to the quiescent level. During
the rapidly declining phase, long-term modulations with a period of 86 min and
strong pulses with a period of 8.6 min were observed. We concluded that 86 min
and 8.6 min are the orbital period and the spin period of HT Cam, respectively.
By the detection of the spin period, we confirmed the IP classification of HT
Cam. However, its outburst behavior rather resembles that of dwarf novae.
The discrepancy between the declining rates of the total flux and the pulse
flux strongly suggests that the disk instabilities were taking place during the
outburst.Comment: 7 pages, 8 figures, accepted for publication in PAS
Long-term monitoring of the short period SU UMa-type dwarf nova, V844 Herculis
We report on time-resolved CCD photometry of four outbursts of a short-period
SU UMa-type dwarf nova, V844 Herculis. We successfully determined the mean
superhump periods to be 0.05584(64) days, and 0.055883(3) for the 2002 May
superoutburst, and the 2006 April-May superoutburst, respectively. During the
2002 October observations, we confirmed that the outburst is a normal outburst,
which is the first recorded normal outburst in V844 Her. We also examined
superhump period changes during 2002 May and 2006 April-May superoutbursts,
both of which showed increasing superhump period over the course of the plateau
stage. In order to examine the long-term behavior of V844 Her, we analyzed
archival data over the past ten years since the discovery of this binary.
Although photometry is not satisfactory in some superoutbursts, we found that
V844 Her showed no precursors and rebrightenings. Based on the long-term light
curve, we further confirmed V844 Her has shown almost no normal outbursts
despite the fact that the supercycle of the system is estimated to be about 300
days. In order to explain the long-term light curves of V844 Her, evaporation
in the accretion disk may play a role in the avoidance of several normal
outbursts, which does not contradict with the relatively large X-ray luminosity
of V844 Her.Comment: 10 pages, 11 figures, accepted for PAS
The 2006 November outburst of EG Aquarii: the SU UMa nature revealed
We report time-resolved CCD photometry of the cataclysmic variable EG Aquarii
during the 2006 November outburst During the outburst, superhumps were
unambiguously detected with a mean period of 0.078828(6) days, firstly
classifying the object as an SU UMa-type dwarf nova. It also turned out that
the outburst contained a precursor. At the end of the precursor, immature
profiles of humps were observed. By a phase analysis of these humps, we
interpreted the features as superhumps. This is the second example that the
superhumps were shown during a precursor. Near the maximum stage of the
outburst, we discovered an abrupt shift of the superhump period by
0.002 days. After the supermaximum, the superhump period decreased at the rate
of =, which is typical for SU UMa-type dwarf
novae. Although the outburst light curve was characteristic of SU UMa-type
dwarf novae, long-term monitoring of the variable shows no outbursts over the
past decade. We note on the basic properties of long period and inactive SU
UMa-type dwarf novae.Comment: 9 pages, 7 figures, accepted for PAS
Superhump Evolution in the Ultrashort Period Dwarf Nova 1RXS J232953.9+062814
Abstract
We report on the evolution of superhumps and late superhumps in an ultrashort period dwarf nova, 1RXS J232953.9062814, during the superoutburst in 2001 November. Ordinary superhumps were observed throughout a plateau phase, a rapid fading phase, and a rebrightening phase. During the plateau phase, the superhump period increased with time at a large rate of . In conjunction with the rebrightening phenomenon, these characteristics indicate that an accretion disk expanded further outward from the resonance radius, which caused a large amount of left over matter at the outer disk, even after the superoutburst. In the post-outburst phase, we detected late superhumps superimposed on dominant double-peak modulations. Late superhumps were observed at least for 10 d without a significant period change. We detected the first normal outburst of this object on 2001 December 26. The interval between the superoutburst and this normal one is 53 d. This short recurrence time supports a high mass-transfer rate in this system. Concerning the evolutionary status of 1RXS J232953.9062814, we propose that it is a progenitor of AM CVn stars on the evolutionary course of the cataclysmic variable channel in which systems have a secondary star with a hydrogen-exhausted core
カテイ ソウゴウ キョウカショ ニオケル セイカツ カダイ ノ トリアツカイ : ショクヒン ノ アンゼンセイ ショク ト エイヨウ イセイカツ ブンカ イフク ノ サイズ ヒョウジ ニ カンスル キジュツ ノ コウサツ
「家庭総合」教科書における生活課題の記述を検討し,今後改善すべき点をあげた。食品の安全性については食の安全性に関する新たな課題を取り上げること,食と栄養については高校生の食生活の実践を促すための具体例を,衣生活文化については実習例を多く取りあげること,サイズ表示に関しては的確な記述が求められる。The purpose of this study was to analyze subjects of living in Integrated Home Economics. The results were as follows: 1. The new subjects about safety of food are necessary to learn. 2. Food and nutrition have to be described with specific ezample to practice for high school students. 3. Culture of clothing life are necessary to learn with the practical lerarning. 4. The size indication of clothing have to be described accurately.国立情報学研究所『研究紀要公開支援事業』により電子化
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae
We systematically surveyed period variations of superhumps in SU UMa-type
dwarf novae based on newly obtained data and past publications. In many
systems, the evolution of superhump period are found to be composed of three
distinct stages: early evolutionary stage with a longer superhump period,
middle stage with systematically varying periods, final stage with a shorter,
stable superhump period. During the middle stage, many systems with superhump
periods less than 0.08 d show positive period derivatives. Contrary to the
earlier claim, we found no clear evidence for variation of period derivatives
between superoutburst of the same object. We present an interpretation that the
lengthening of the superhump period is a result of outward propagation of the
eccentricity wave and is limited by the radius near the tidal truncation. We
interpret that late stage superhumps are rejuvenized excitation of 3:1
resonance when the superhumps in the outer disk is effectively quenched. Many
of WZ Sge-type dwarf novae showed long-enduring superhumps during the
post-superoutburst stage having periods longer than those during the main
superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to
be strongly correlated with the fractional superhump excess, or consequently,
mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with
multiple rebrightenings tend to have smaller period derivatives and are
excellent candidate for the systems around or after the period minimum of
evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte