Return to Home Page
Date: Wed, 21 Jul 93 10:43:31 PDT From: mauche@imager4.llnl.gov (Christopher Mauche) Subject: optical observations of CVs during ORFEUS mission ----- Begin Included Message ----- >From mauche Fri Jul 16 15:33:43 1993 To: nova@nova.la.asu.edu Subject: optical observations of CVs during ORFEUS mission Content-Length: 4086 X-Lines: 95 REQUEST TO MONITOR CATACLYSMIC VARIABLES DURING ORFEUS MISSION On Saturday, July 17, 1993, NASA's Space Shuttle Discovery is scheduled to launch and subsequently to deploy a German-built, free-flying space platform equipped with an international cargo of science instruments. This first mission of the NASA/German Space Agency (DARA) ASTRO-SPAS platform is called ORFEUS (Orbiting and Retrievable Far and Extreme Ultraviolet Spectrograph). ORFEUS is a 1 meter normal-incidence telescope designed to obtain high-resolution EUV and far-UV spectra using an Echelle (Heidelberg/Tubingen) and Rowland (UC Berkeley) spectrometer. Further information on the mission can be found in "Extreme Ultraviolet Astronomy," ed. R. F. Malina and S. Bowyer. In collaboration with the UCB team, John Raymond (CfA) and Chris Mauche (LLNL) have included the UX UMa-type nova-like variable V3885 Sgr on the prime target list. If the length of the mission is extended (a toilet on the Shuttle backs up or it rains in Florida), it may be possible to add a magnetic cataclysmic variable to the target list. In addition, it is our hope to be able to add one or more targets of opportunity to the target list to observe a dwarf nova in outburst. So that we may be notified in the event that such an opportunity exists, we have solicited the assistance of the AAVSO. On July 7 an alert notice was sent to their observers world-wide. The sources include: Coordinates (2000) Name Comment hh mm ss.s deg mm ss ------------------------------------------------------------- 19 47 40.3 -42 0 28 V3885 Sgr Prime Target 08 25 13.2 +73 6 40 Z Cam Target of Opportunity 21 42 42.3 +43 35 8 SS Cyg Target of Opportunity 04 9 11.3 -71 17 42 VW Hyi Target of Opportunity 01 4 35.5 +41 17 58 RX And Target of Opportunity 22 14 2.5 +12 42 11 RU Peg Target of Opportunity 18 16 13.3 +49 52 3 AM Her Possible Target^* 03 14 12.8 -22 35 40 EF Eri Possible Target^* 14 9 7.4 -45 17 16 V834 Cen Possible Target^* ------------------------------------------------------------- ^*Target may be added to the timeline if the mission is extended. As of the evening of July 15, it is our understanding that: (1) RX And is at the peak of an outburst which began on July 10. It is likely that this source will decline from outburst before it can be targeted, but we are watching it carefully. (2) Z Cam is in standstill. Every expectation is that it will continue to be bright throughout the ORFEUS mission, making this source an attractive target for observations. (3) AM Her is in its bright phase, making it an attractive target for observations. (4) SS Cyg is currently in quiescence, having had an anomalous outburst beginning on May 20. As nearly 60 days have elapsed since that time, there is some chance that this source will go into outburst during the ORFEUS mission. We will be watching this star closely. (5) RU Peg is in quiescence. (6) No info on VW Hyi, but D. Overbeek from South Africa is monitoring this star closely and will report to us if it goes into outburst. Since ORFEUS's bandpass extends down to only ~1250 Angstroms, we have made arrangements with Yoji Kondo and Sumner Starrfield to obtain IUE spectra of our ORFEUS targets. It the intention of this notice to alert ground-based optical observers of the need for simultaneous and near-simultaneous photometry and spectrometry of our sources during the ORFEUS mission. Unfortunately, it is not possible at this time to specify the time that observations of any of our sources will take place, as the timeline for the mission depends on the exact time the Shuttle launches and when ACTS-TOS (the other satellite on the mission) is deployed. It is our best guess that ORFEUS observations will begin on flight day 2 or 3 of the mission. Interested observers are encouraged to contact Chris Mauche at: mauche@imager.llnl.gov e-mail for further information as the mission proceeds. ----- End Included Message -----
Return to the Powerful Daisaku
vsnet-adm@kusastro.kyoto-u.ac.jp
