Return to Home Page
I have been working on the same field for a couple days now. There is new photometry from Henden covering several of the brighter stars included on both AAVSO and Otero's charts. The existing AAVSO sequence for RS Oph has few real problems. Webbink's values match quite well with Henden's from 9.3-13.3 where a direct comparison can be made. The brighter mags seem to match well with Tycho. The one significant outlier, as Linnolt has mentioned, AAVSO 113 SE of the variable, is quite red (B-V 1.6) and actually 11.1V. I prefer not to use red stars in sequences, but in some areas near the galactic equator there is little choice in the matter. There are several red stars in both sequences, but as long as observers report the comparison stars used and chart information to AAVSO with their reports this should not be a significant problem. The bright star marked var? south of RS Oph on Sebastian's chart (AAVSO 93) is not likely variable and should be retained as a comparison. The measurements from ASAS 3, Tycho and Henden (recent) all agree. Tycho-2 9.34V, B-V 1.22 Henden 9.319V, B-V 1.171 ASAS-3 data is 9.31V. The source of concern on Otero's part was from his use of the magnitudes in Arne's original data, which is saturated at this level and therefore unreliable. Needless to say, anyone lucky enough to use this comparison in making an estimate or measure will be witnessing something special! As mentioned elsewhere, there is a typo in the declination for RS Oph on Otero's chart. It should be -06 42 28.6 not -06 42 18.6. The recent reported brightening of RS Oph does seem to be real. Henden's most recent observation (of unknown specific date UT, sorry) is 10.759V, B-V 1.108 with errors expected to be +/-0.003. Whether or not RS Oph is ready to impress us again is yet to be seen. But I seem to recall WZ Sge was a little earlier than expected this time around, so you never know, do you? That is what makes this so much fun. There seems to be some discrepancy as to whether RS Oph is a NRa or NRb between GCVS and Webbink's paper. Any comments/clarification on this would be most welcome. There is a very good article on RS Oph by Kerri Malatesta, in the Variable Star of the Month archives at AAVSO http://vsnet.aavso.org/vstar/vsotm/0500.stm that also points to a bounty of useful information. (If you go to the above link you will find active links to several of these resources) Mike Simonsen
Return to the Powerful Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
