*** News from VSNET *** The very short period dwarf nova, V485 Cen is now undergoing an outburst. For more detail information about these objects, see below, "VSNET Weekly Campaign Summary" of the last week. --------------------------------------------------------------------------- VSNET (Variable Star Network) is an international variable star observing network, covering various areas of novae, supernovae, cataclysmic variables (CVs), X-ray transients, and other classical eruptive, pulsating, and eclipsing variables. VSNET is one of invited contributing organizations to the SkyPub AstroAlert system. The "News from VSNET", mainly focusing on recent remarkable activities of CVs and related systems, is issued on a weekly basis, except on occasions of extremely urgent or transient events. Please refer to the VSNET Home Page for more details of events and objects listed. VSNET Home Page: http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/ VSNET provides a number of mailing lists, on which various news and topics are discussed. Subscriptions to the VSNET mailing lists are free of charge; please refer to the instruction on the above page if a reader needs more information of the list structure. CCD observations of such targets are a relatively easy task for a 20-40cm telescope; simply take as many CCD frames (with exposure times 10-30 sec) as possible, spanning several hours per night. The only requirements are the weather and your patience! If you need more help on the observing technique, please feel free to ask on the vsnet-campaign list. We would sincerely appreciate volunteers who would join the VSNET Collaboration team to study the wonders of these exotic variable stars. To join the VSNET campaign collaborative list, send an e-mail to vsnet-adm@kusastro.kyoto-u.ac.jp (VSNET administrator) with a line "SUBSCRIBE vsnet-campaign." (VSNET campaign members are strongly recommended to subscribe to vsnet-alert at the same time). Regards, Taichi Kato On behalf of the VSNET administrator team ---------------------------------------------------------------------------- The following was issued on Apr. 3, 2001, as VSNET campaign circulation 836. [Note a large part of detailed information is posted to vsnet-campaign sub-lists]. VSNET Weekly Campaign Summary *** Last week news *** (new targets) V485 Cen (RA = 12h57m23s.30, Dec = -33d12'06".8) The dwarf nova V485 Cen is undergoing an outburst (14.1mag) as reported by R. Stubbings on March 29. The brightness and the outburst interval suggests a superoutburst. V485 Cen is known to be a unique dwarf nova having an orbital period of 59 min, which is well below the "minimum period" of hydrogen-rich cataclysmic variables (vsnet-campaign 832). The outburst still continues (vsnet-campaign-dn 616). IR Com (RA = 12h39m32s.09, Dec = +21d08'05".6) The short-period eclipsing dwarf nova IR Com experienced an outburst (14.0mag) as reported by M. Simonsen on March 25. The reported duration seems to be longer than those of previous normal outbursts (vsnet-campaign 829). Since March 28, relatively rapid decline trend was confirmed (vsnet-campaign-dn 611). NY Ser (RA = 15h13m02.39s, Dec = +23d15'07".1) NY Ser, the SU UMa-type dwarf nova with a long (orbital) period, is undergoing a bright (14.2mag) outburst as reported by M. Simonsen on March 27. The outburst may be a superoutburst. The Kyoto team had obtained some immediate pre-superoutburst data (vsnet-campaign 828). Z Cha (RA = 08h07m16s.29, Dec = -76d32'20".9) The eclipsing SU UMa-type dwarf nova Z Cha is in outburst (11.8amg) as reported by R. Stubbings on March 26. The brightness may suggest a superoutburst (vsnet-campaign 830). The outburst still continues (vsnet-campaign-dn 614, 617). V405 Aur (RA = 05h57m59s.29, Dec = +53d53'44".8) S. O'Connor and M. Reszelski reported that the intermediate polar V405 Aur is in active state (13.6-13.8mag). MV Lyr (RA = 19h07m15s.93, Dec = +44d01'10".7) M. Simonsen's observation on March 28 shows the nova-like variable MV Lyr is recovering (14.4mag) from faint state (vsnet-campaign-nl 10). V1504 Cyg (RA = 19h28m55.87s, Dec = +43d05'39".9) V1504 Cyg experienced an outburst (13.9mag) as reported by T. Kinnunen on March 30 (vsnet-campaign 833). (continuous targets) V445 Pup (RA = 07h37m56s.88, Dec = -25d56'59".1) The object slightly brightened (~10.0mag) around March 26 (vsnet-campaign-nova 275), and then again gradually faded (vsnet-campaign-nova 277). DW Cnc (RA = 07h58m56s.80, Dec = +16d16'48".2) Time-series photometry taken by J. Pietz on March 27 shows a hump-like modulation with an amplitude of 0.4mag (vsnet-campaign 834). In his data on March 30, the modulations are less prominent. M. Uemura reported that combined light curve of the VSNET collaboration team show 0.053 and 0.027 day periodicity, but not strong (vsnet-campaign 835). The bright state continues. Delta Sco (RA = 16h00m19s.9, Dec = -22d37'17") The bright state continues (vsnet-campaign-be 65). W Com (RA = 12h21m31.5s, Dec = +28d13m57.6s) The blazar W Com is brightening to 14.0mag as reported several observers on March 26 (vsnet-campaign-blazar 172). V4643 Sgr (RA = 17h54m40s.43, Dec = -26d14'15".7) After the short plateau, the object again faded rapidly. 13.1 mag was reported on March 23 and 24 (vsnet-campaign-nova 276). V803 Cen (RA = 13h23m44.5s, Dec = -41d44'30".1) The activity seems to be calm during March 26 and 27 (vsnet-campaign-dn 612), and then modulated between 13.9-14.3mag during March 27-29 (vsnet-campaign-dn 615). U Gem (RA = 07h55m05s.55, Dec = +22d00'09".2) The slightly bright state continues (vsnet-campaign-dn 613). SN 2001V (RA = 11h57m24s.93, Dec = +25d12'09".0) The object is currently at 14.8-14.9mag (vsnet-campaign-sn 169). V893 Sco (RA = 16h14m45.26s, Dec = -28d39m30.3s) The dwarf nova again experienced an outburst (12.7mag) as reported by R. Stubbings on March 31. The brightness suggests a normal outburst (vsnet-campaign-dn 618). *** Future schedule *** RZ LMi campaign conducted by J. Patterson on April 2001 For more information, see [vsnet-campaign 718, vsnet-campaign-dn 429]. Elizabeth and Frederick White Workshop AGN variability across the Electromagnetic Spectrum 25 - 29 June 2001 Sydney, Australia For more information, see [vsnet-campaign-blazar 168]. Two Years of Science with Chandra * * This meeting will also be the 12th Annual Maryland Astrophysics Conference September 5-7, 2001 For more information, see [vsnet-campaign-xray 66] *** General information *** Z Cha eclipse ephemeris, see [vsnet-campaign 827] U Gem eclipse ephemeris, see [vsnet-campaign-dn 610] IR Com eclipse ephemeris, see [vsnet-campaign 831] (This summary can be cited.) Regards, Makoto Uemura