Dear CBAers,Most of the northern targets we're following are going great guns: BK Lyn and ER UMa are re-writing record books (and we're rewriting them too, for diligence of tracking). BH Lyn has a weaker signal, but is starting to define itself through the fog. All three stars show evidence (the first two are obvious) of simultaneous positive and negative superhumps. We've seen a few examples of this before, but with great coverage can trace how the two interact - and to what extent they participate in eruptions.
RZ LMi is also well worth following. We don't have much data yet this year, but I expect it to be very rewarding.
I'm inclined to take DW UMa off the list. Humps this year, other than orbital, are weak - hard to distinguish amid the large orbital modulation.
And in its place I propose LN UMa = "UMa 7". Possibly a similar star, and one we have little acquaintance with (just one season). And V355 UMa = SDSS1339+48. The latter is quite faint, about 17, but will be fascinating to watch for its post-eruption behavior.
In the south, we've discontinued CP Pup (seasonal, plus an embarrassment of riches) and V393 Hya (sigh, just not doing anything this year). In their place I suggest SW Sex, plus the helium stars CR Boo and V803 Cen.
Especially CR Boo - for all hemispheres. I hope to make this one the centerpiece of our March->May observing.
joeP.S. Just registered and sent in a BK Lyn abstract for the SAS meeting - where I hope to see a bunch of you! (I attach the abstract)
Attachment:
bklynabs.odt
Description: application/vnd.oasis.opendocument.text
THE TORTURED ACCRETION DISK OF BK LYNCIS
Joe Patterson (Columbia U.)
Jonathan Kemp (Gemini Observatory)
and stations of the Center for Backyard Astrophysics:
Enrique de Miguel (Spain), Tom Krajci (New Mexico), Bob Koff (Colorado), Jerry Foote (Utah), David Cejudo (Spain), David Skillman (Maryland), Shawn Dvorak (Orlando), Tut Campbell (Arkansas), George Roberts (Tennessee), Josch Hambsch (Belgium), Joe Ulowetz (Illinois), David Messier (Connecticut), Tonny Vanmunster (Belgium)
BK Lyncis is a 15th magnitude nova-like variable with an orbital period of 107 minutes.
We report on 2500 hours of time-series photometry with 1-minute time resolution over ten
observing seasons during 1998-2012. The star displays large-amplitude positive and
negative superhumps, which vary in amplitude and phase on a timescale of a few months.
The strength and persistence of the signals make the star a beautiful candidate for detailed
study ? and the superhumps are consistent with interpretation as (simultaneous) apsidal
and nodal precession of the accretion disk.
BK Lyn's high luminosity has always been remarkable and unexplained ? about fifty
times greater than its compadres at short orbital period, all of whom are dwarf novae. In 2012, the star may have had a dwarf-nova outburst, the first ever seen. We conjecture that the star is "the oldest old nova? ? the remant of the 101 A.D. "guest star", and taking ~2000 years to resume life as a dwarf nova.