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I also watched the webinar last night. I had a look at the TESS data for T CrB later but not too interesting: You see the orbital period and the flickering ( on all timescales). There are only 3 28 day periods that TESS has observed it.
I found the lack of understanding of the “high state” and “secondary brightening” after 100 days post eruption and interesting.
The most recent two superoutbursts (JD24598001 and JD2459853) were observed by the TESS satellite giving a very short supercycle period of only 53 days. Analysis of the last 800 days of AAVSO light curve suggests a gradual shortening of the cycle period. I’ll try to write this up in time for the next VSSC.
If the current super outburst cycle is 52 days, we can expect the next superoutburst to start on JD2459905 or about November 20. Again thanks to the, at least, nine BAA members who are following this star.
With a screen shot
I had a look at the AAVSO curve, dominated by Max’s data of course (impressive). The last period 2459700 to present reminds me of an ER UMa star in that there are two bright outbursts with a series of smaller ones between. The brighter outbursts seem to be 70 days apart.
There are no TESS observations unfortunately.
Ive added it to my SLOOH watch list for Canary.
IX Dra is now in outburst (probably superoutburst) based upon two nights observations by AAVSOnet New Mexico and three by R Sargent.
The previous superoutburst started 57-58 days ago. Hopefully more data from other observers, TESS and Lasair will refine the start date. This value (57-58 d) is unremarkable compared to the previous 10 superoutburst periods and suggests some stability.
Thanks to those making observations.
ER UMa has been observed through May by R Sargent, G Poyner, PB Withers, S Johnston, ND James yielding good coverage of the May 12 superoutburst. So far in this observing season, the superoutburst period has an average value of 45 days. This is fairly low compared to the graph presented in VSSC 188 one year ago ( see attachment).
Maybe the super-cycle period has a minimum value of about 40-45 days with occasional excursions to higher values? Only long term observations can illuminate this topic. The next superoutburst will be at the end of June if 45 days remains a reliable estimate.
RZ Lmi continues to show 26-27 days super-cycle periods consistent with a steadily increasing period length. The rate of change appears to be about 0.2 days per year as presented in VSSC190. Fewer observers follow RZ Lmi probably because it is a magnitude less bright than ER UMa but it compensates by always changing state. The next superoutburst may be on June 14.
My own observations are all via AAVSOnet or SLOOH. My thanks to those two organisations.
Definitely in superoutburst now. V mag is brighter than 13.0 last night.
Richard, Looks like you may have captured the start of the superoutburst. At the same time Steve Johnson made very similar observations reported to AAVSO.
A little later (UTC 2022/05/12 03:36:29 JD 2459711.65 ), using AAVSOnet New Mexico, I got a V magnitude of 13.1 which is in superoutburst territory. So it will probably remain bright for the next 5-10 days. If the superoutburst has started, it is 50 days from the last start – which is typical.
ER UMa is likely to go into superoutburst in the next few days. The last superoutburst started at 2459660. The superoutburst period varies between 45- 55 days. It is now 50 days since the last outburst.
Further observations this week would be timely.
An update on IX Dra recent behaviour. Observations are been made by the AAVSOnet telescope in New Mexico, by BAA-VSS, and by AAVSO members.
The most recent superoutburst was well recorded by AAVSOnet telescopes with a start around JD 2459688.
TESS contributed a detailed record of the superoutburst at JD 2459633.
The previous superoutburst was well recorded at JD 2459577.
The next previous superoutburst was well recorded on JD 2459520.
Graphing the most recent data gives the data in the attachment. This shows a declining trend from a peak around 60 days. The data point at JD 2459106 is almost certainly too high owing to limited observations. Observations were available only once the outburst had started so the start must be uncertain by a few days.
It seems that for IX Dra the trend towards longer superoutburst periods has paused. It may be reversing.
Thanks to all who have, and continue to, contribute to following this star.
- This reply was modified 1 year, 7 months ago by Stewart John Bean.
The TESS satellite captured the most recent superoutburst completely. I estimate a start date of JD 2459633.
The most recent estimated super outburst start dates are complied below. Sources are BAA database, AAVSO DB and TESS results.
9633 56 TESS image below
These give an average of 58.5 days.
Thanks to all contributing to these measurements
Attachments:5 January 2022 at 4:50 pm in reply to: Suggestions for CV stars in the Southern Hemisphere #585083
I have come across a paper by Kato et al “Photometric study of new southern SU UMa-type dwarf novae
and candidates: V877 Ara, KK Tel and PU CMa”
So I am occasionally imaging PU CMa as it may be coming up for a superoutburst in January/February. The other two will be better placed in the spring.
In the meantime, I have joined G Poyner and IL Walton in following V1159 Ori.
Measured ER UMa at 12.9 CV on 2021/12/28 03:08:50 using SLOOH in the Canaries. Hopefully some more results will arrive to refine the timing of what appears to be a superoutburst.
This is only ~45 days after the start of the last one. Most periods lie in the range 45 to 60 days – so quite short. See VSSC188 for a full graph of super cycle period over the last 200 or so cycles for context.
My prediction was one day early, but that is consistent with the superoutburst period very gradually getting larger. The last period was 26 days as I judge it.
Actually, this seasons light curve has good coverage as Sjoerd Dufoer (BE) has made 52 observations. Gary Poyner and Raymond Pearce have contributions as well. Thanks to all three.
Stewart2 December 2021 at 2:50 pm in reply to: Suggestions for CV stars in the Southern Hemisphere #584963
I really mean those that can be observed from one of the remote telescopes at the latitude of, say, Santiago, Chile. There are not many in VSX but V1159 Ori is one. V1159 Ori is a good candidate (UGER) as it can be observed from both hemispheres giving a good temporal coverage. Brightness in the range 13.5 to 15.5 so easy enough. Its also one of the topics in M. Otulakowska-Hypka and A. Olech, MNRAS 433, 1338–1343 (2013) so I will get into its ~50 day supercycle at some point.
Interest has been heighten by recent poor weather on Tenerife.
now in Gloucestershire.
As mentioned by Jeremy in VSSC 190 (the latest) several ER UMa stars are due a superoutburst before the year end. With a disclaimer on the accuracy of the dates, I copy below my expectations for four stars.
Superoutburst period (d) Next superoutburst (give or take a few days)
RZ LMi 25 Dec 11 Late evenings
V1159 Ori ~50 Dec 22 A late evening target
IX Dra 60 Dec 30 An early evening target
ER Uma 50-55 Dec 30 – Jan 2 Late evening target
Stewart26 November 2021 at 4:44 pm in reply to: Suggestions for CV stars in the Southern Hemisphere #584936
Thx for your help. I’ve found UU Aql as a suitable target. Its listed as UGSS type in VSX although the data are a little sparse.
Plenty of images being taken on SLOOH Chile telescopes tonight by users.
I make is 13.5 CV in the image
Here is an image from last night from SLOOH Chile 2. The marked star corresponds to the SN coordinates
I’ll give it a go from Slooh Chile tonight