(cba:news) Stars for June

Joe Patterson jop at astro.columbia.edu
Tue May 30 14:39:43 EDT 2000

 Dear CBAers,                                              May 30, 2000

     Back from a run (Jonathan's last) at MDM, and getting ready to go
off to the AAS meeting and then a few weeks in Arizona.

     The campaign on the UMa X-ray transient continues apace.  The "10-
second" quasi-period continues to evolve toward shorter periods -
has trucked all the way from 12.4 s to 7.9 s in the last 50 days.  The
4.1 hr signal discovered by Lew back in March has shown a little bit of
movement, suggesting it is probably a superhump rather than strictly
Porb - but the distinction is still pretty weak and will need probably
another 3 weeks of data to firm up.  If you're doing UMa, keep at it
for a few weeks - but too late in the season to start anything.

     Jennie and Fred popped up with four nights of KK Tel in
superoutburst, and this was sufficient to yield the superhump period of
.08764(16) d.  Jonathan's earlier photometry at quiescence gave
Porb=0.08452(15) d.  Well done - one more epsilon to rack up!
(=0.037+-0.002).  We can retire KK Tel now.

     Tonny's friend, the Hamburger star (RX J1450.5+6403).  Some very
nice results on the superhump.  I *think* we have enough on this now,
but I'm not altogether sure since I haven't worked on it myself.
Tonny, do you think so?  (Remember that John Thorstensen will almost
certainly nail down Porb from spectroscopy in early July, so we don't
need to beat on that.)

     The two good stars for long coverage right now are V849 Her (=Her
2 = PG1633+115) and V1315 Aql.  These both have periods in the 3-4 hr
range, and probably both have large-amplitude superhumps.  And they're
both equatorial, enabling us to use our longitude to maximum advantage!
These are the guys to go after.  For shorter coverage, the DQ Her stars
(AO Psc, FO Aqr, V1223 Sgr) are the prime targets, along with HP Lib.


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