Return to Home Page
> According to the ASAS-3 survey data, the R CrB-like star > DY Cru may be steadily fading (currently around V=8.8). Dear all, ...and first of all, what a treasure the ASAS-3 catalogue is!! I have analised the data and prepared a lightcurve combining my observations and those form ASAS-3. There is a wide spread of magnitudes between different apertures for DY Cru that can reach as much as 0.4 mag. I have taken the most consistent values I found, in this case the "mag. 1" results. Comparing my observations with the 5 different apertures I found that the magnitudes for "mag.3" are in agreement with my visual data so I measured the average difference between the consistent "mag.1" data and the "mag.3" dataset that matches my observations well (there is no way to say if the zero-point is totally correct but it gives the possibility of getting a nice and comparable lightcurve). The resulting magnitudes were folded in the lightcurves at: http://ar.geocities.com/varsao/Curva_DY_Cru.htm Some things are apparent: Between JD 2451880 and 2452150, the star underwent a typical pulsation cycle, approximately 270 days-long The end of the cycle is not observed so it can be longer). This smooth variation was followed by a more chaotic behaviour (as it was before JD 2451880). An inset for the last months shows only low amplitude variations in shorter time-scales. A maximum seems to have been missed around JD 2452560. Last weeks there is a more marked discrepance between different ASAS-3 datasets. The highest maxima are around: JD Mag ~2450930 8.4 ~2451480 ~8.5 2452030 8.45 2452560 ~8.6 or 530-550 days apart The deepest minima are around: 2451350 9.8 2451880 9.7 ~2452400 ~9.1 or 520-530 days apart However, there are a lot of ups and downs in the middle including long standstills such as that between HJD 2451570 and 2451800 (V= 8.9-9.1) that even included another maximum around JD 2451750 (270-280 days apart from the brightest maxima mentioned above or almost half a cycle) I would keep calling it an L-type star... The present behaviour is completely normal, the star being around V= 9.1 Best regards, Sebastian.
Return to the Powerful Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
