AAVSO International Database

March 2, 2010: Dr. Bradley Schaefer (LSU) requests intensive time-series observations of U Scorpii beginning immediately and continuing through 2010 March 4 08:00 UT (JD 2455259.83). These observations are requested in support of coincident X-ray photometry by the XMM-Newton satellite. The XMM-Newton observations, requested by Dr. Jan-Uwe Ness (ESA), will investigate the X-ray behavior of U Sco during its transition from outburst back to quiescence.

March 9, 2010: The old nova (1901) and x-ray source GK Per may be going into outburst. Reports beginning late on 2010 March 6 UT show it brightening from its minimum visual magnitude of about 13.1 to 12.3-12.4.

 

When GK Per went nova in 1901, its disk was destroyed. Eventually the disk was re-established, and dwarf nova-like outbursts were observed.

March 8, 2010: Further to Alert Notice 417, the AAVSO requests intensive monitoring observations of the cataclysmic variable GW Librae beginning immediately (2010 March 9.0 UT; JD 2455264.5) and continuing through 2010 March 12.5 (2455268.0). These observations are in support of the Hubble Space Telescope Cosmic Origins Spectrograph observations of GW Lib planned for 2010 March 11 UT. Space Telescope ground controllers will need to know that GW Lib is fainter than V=15 in order to proceed with the planned observations.

March 9, 2010: Observer Tomas L. Gomez (Madrid, Spain) reports that the infrequently outbursting dwarf nova KX Aql is currently in outburst. Gomez detected the star at an unfiltered magnitude of 13.58 on 2010 March 9.242 UT (JD 2455264.742). This system has been poorly observed over the past few months; the most recent observation of KX Aql was also by T.L. Gomez, who reported a fainter-than unfiltered magitude of < 15.12 on 2010 February 20.2617 (2455247.7617).

March 12, 2010: Further to Maehara et al. (CBET 2199, D.W.E. Green, editor), the presumed symbiotic star V407 Cyg appears to be undergoing a very bright outburst, well outside of its previous range. This outburst was discovered independently by the team of K. Nishiyama (Fukuoka, Japan) and F. Kabashima (Saga, Japan), and by T. Kojima (Tsumagoi, Agatsuma-gun, Gunma-ken, Japan). Nishiyama and Kabashima observed the star at an unfiltered magnitude of 6.8 on 2010 March 10.813 (JD 2455266.313) and magnitude 6.9 on 2010 March 10.814 (2455266.814).

March 14, 2010: Further to Munari et al. (CBET 2204, D.W.E. Green, editor), the presumed symbiotic star V407 Cyg is exhibiting spectral features clearly indicating a classical nova of the He/N type. This strongly suggests that the white dwarf component of the system is currently undergoing a nova outburst rather than a symbiotic-type outburst. The spectral evolution of this nova may be very fast given the likely large mass loss rate of the Mira-type donor star. We urgently request observations of V407 Cyg to provide photometric coverage of this unique event.

March 15, 2010: Further to AAVSO Alert Notice 418, the AAVSO requests intensive monitoring of the cataclysmic variable V842 Cen in support of Dr. Paula Szkody's upcoming Hubble Space Telescope observations beginning now (2010 March 15.85; JD 2455271.35) and continuing through 2010 March 19. Observations are requested to show HST ground controllers that the system remains faint and is therefore safe to observe.

May 22, 2010: Rod Stubbings has reported that the infrequently outbursting dwarf nova EX Hydrae is in outburst. Stubbings reported the star at a visual magnitude of 9.4 on 2010 May 22.667 (JD 2455339.167) and it remained at 9.4 through May 22.721 (2455339.221). Both visual and instrumental observations of EX Hya are urgently requested. CCD observers, please obtain time-series photometry if at all possible.

May 19, 2010: Dr. Gordon Sarty, University of Saskatchewan, Canada, requests our continuing assistance in his ongoing observations of High Mass X-ray Binaries (HMXBs). Dr. Sarty provides the following text for the current request:

 

"Please obtain BVRI photometry (or any subset thereof, VI preferred) of the following four HMXBs for the time period of our radial velocity observations to be made with the 72-inch Plaskett telescope at the Dominion Astrophysical Observatory (DAO) from now until June 30.

May 17, 2010: Dr. Michael Sitko (U. Cincinnati) requests observations of the young stellar object TW Hya in support of upcoming Hubble Space Telescope observations. TW Hya is believed to be a T Tauri star that varies between magnitudes 10.5 and 12.2. TW Hya will be observed with the HST STIS instrument as part of a larger program to study the properties of potentially planet-forming disks around young stars. The star will be observed in the ultraviolet to search for time-variability in the gas in the inner accretion disk.