Yes we've started a significant update to the web page and have migrated all content to the AAVSO system from the Google web page. I have taken over as administrator of the Section ably assisted by Mike Soukup and Frank Schorr. Please bear with us over the next few months as we complete the migration process and iron out all the formatting issues. We hope to keep the page fresh and updated often so I would encourage all to frequently check back in.
I think another list of LPVs with period changes is a great idea! Perhaps the LPVs with period changes (and even type changes like T Umi and others) might be having very significant changes on going that should be followed!
Can we start a list of period changing LPVs using the stars you have listed?
Identifying Miras with period changes has to be done with care. A comprehensive study by Templeton, Mattei and Willson (2005 AJ 130, 776) identified a small fraction of Miras that had large period changes which were most likely due to evolution. But all Miras have (O-C) diagrams that appear to show period changes, but are actually due to the accumulation of random cycle-to-cycle fluctuations in period (Percy and Colivas 1999 PASP 111, 94). These are of no particular interest, individually, but Thomas Karlsson (2014 JAAVSO 42, 280) has averaged these over 362 Miras and detected the underlying evolutionary change at about the 2-sigma level. A student and I had done the same, back in 1999 (PASP 111, 98) and found the same result at about the 1.5-sigma level. We could certainly compile a list of about 30 stars from Templeton et al., plus a few others which have changed their amplitudes systematically. It's worth observing the rest of the Miras on the AAVSO visual program, but it doesn't have to be intensive observing.
We've justed added the first article to our LPV of the Month web page. I invite you to check it out. The star for June is L2 Puppis. Apologies to our northern hemisphere observers as it is a southern object. However it is a very interesting star so we hope you enjoy the read.
We will hopefully cover a mixture of northern and southern hemisphere stars on a monthly basis which will hopefully motivate observers to follow these interesting stars.
If you're interested in putting together a short article on your favourite LPV, we'd love to hear from you. The intention is to make the page as collaborative as possible with multiple contributors rather than just us administrators!
Hi Hubert and all
Yes we've started a significant update to the web page and have migrated all content to the AAVSO system from the Google web page. I have taken over as administrator of the Section ably assisted by Mike Soukup and Frank Schorr. Please bear with us over the next few months as we complete the migration process and iron out all the formatting issues. We hope to keep the page fresh and updated often so I would encourage all to frequently check back in.
Regards
Andrew Pearce (PEX)
Hello Andrew
Thanks for taking the lead in the LPV Section, and thanks to Mike Soukup and Frank Schorr for their contributions.
Gary
Hi Andrew,
I will keep checking in on regulary bais. Thanks to al the contributors.
Looking real good Andrew! And thanks to Mike and Frank for assisting.
Clear Skies.
Michael
Maybe unify in a list LPV´s with "special features" in the light curve?
This is my personal list. Any suggestions?
Regards
Alfredo Glez-Herrera (GZN)
Hurbert,
There already is a page with a list of 73+ LPVs with "humps" on the LPV section page at https://www.aavso.org/lpv-humps.
I think another list of LPVs with period changes is a great idea! Perhaps the LPVs with period changes (and even type changes like T Umi and others) might be having very significant changes on going that should be followed!
Can we start a list of period changing LPVs using the stars you have listed?
Thanks,
Frank Schorr
Of course!
You are free to do that.
Alfredo Glez-Herrera (GZN)
Dear Colleagues,
Identifying Miras with period changes has to be done with care. A comprehensive study by Templeton, Mattei and Willson (2005 AJ 130, 776) identified a small fraction of Miras that had large period changes which were most likely due to evolution. But all Miras have (O-C) diagrams that appear to show period changes, but are actually due to the accumulation of random cycle-to-cycle fluctuations in period (Percy and Colivas 1999 PASP 111, 94). These are of no particular interest, individually, but Thomas Karlsson (2014 JAAVSO 42, 280) has averaged these over 362 Miras and detected the underlying evolutionary change at about the 2-sigma level. A student and I had done the same, back in 1999 (PASP 111, 98) and found the same result at about the 1.5-sigma level. We could certainly compile a list of about 30 stars from Templeton et al., plus a few others which have changed their amplitudes systematically. It's worth observing the rest of the Miras on the AAVSO visual program, but it doesn't have to be intensive observing.
John Percy
Hi All
We've justed added the first article to our LPV of the Month web page. I invite you to check it out. The star for June is L2 Puppis. Apologies to our northern hemisphere observers as it is a southern object. However it is a very interesting star so we hope you enjoy the read.
We will hopefully cover a mixture of northern and southern hemisphere stars on a monthly basis which will hopefully motivate observers to follow these interesting stars.
If you're interested in putting together a short article on your favourite LPV, we'd love to hear from you. The intention is to make the page as collaborative as possible with multiple contributors rather than just us administrators!
Regards
Andrew
Great work on the new section Andrew!
L2 Pup is fascinating, for sure.
David
So July LPV of the Month is nothern circumpolar, so we northern hemisphere observers can't complain :)
Just realized there is a nice article from 2011 giving some background to T UMi and similar stars' behaviour: Mira Variables with Period Changes.
Thank you for your work, Andrew.