AAVSO Alert Notice 598 Intermediate polar FO Aqr fading and photometry needed now September 6, 2017: Dr. Colin Littlefield (University of Notre Dame) and colleagues have requested AAVSO assistance in monitoring the intermediate polar cataclysmic variable FO Aqr beginning immediately. This campaign is similar to the one on FO Aqr requested by Dr. Littlefield and colleagues in July 2016 (AAVSO Alert Notice 545). Dr. Littlefield and co-authors Gordon Myers (AAVSO), Richard Sabo (AAVSO), Peter Garnavich (Notre Dame), and Mark Kennedy (University College Cork) recently published ATel #10703, and write therein that: "The intermediate polar FO Aqr, which in 2016 underwent the first low state in its observational history (Littlefield et al. 2016, ApJ, 833, 93), has faded by nearly 0.7 mag since 2017 August 10, implying a decrease in the system's accretion rate." Good coverage of the current fading event - only the second observed in this system - is extremely important. In an email Dr. Littlefield writes: "As with the previous campaign, we would like observers to obtain nightly photometric time series of FO Aqr. In order to maximize their usefulness to us, the observations would need to be either V-filtered or unfiltered with a V zeropoint (i.e., unfiltered but using the V magnitude of a comparison star when performing photometry, CV). We would like observers to use a cadence of 60 sec/image or faster, even if this means observing unfiltered, and we would prefer that each time series last at least an hour (preferably a minimum of 2 hrs). Our hope is that the AAVSO could observe FO Aqr until either (1) the end of the current faint state or (2) solar conjunction, which for FO Aqr is in January." Visual observations are also welcome. He continues: "Because last year's fade began during solar conjunction, the drop to minimum went almost entirely unobserved. If this is the start of another deep low state like the 2016 event, it would be the first opportunity to study how FO Aqr's accretion processes change during the drop to minimum. For example, AAVSO observations of the current fade by observers Gordon Myers and Richard Sabo have already provided important evidence of a correlation between FO Aqr's overall brightness and the mechanism by which material accretes onto the system's white dwarf. "We had 16 AAVSO co-authors on our paper about the 2016 low state, and if observations from the new campaign lead to another publication, we would be pleased to offer co-authorship to AAVSO observers who contribute data used in our analysis." Observations in the AAVSO International Database on 2017 September 2.6251 UT show FO Aqr at CV = 14.607 +/-0.010 (MGW, G. Myers, Hillsborough, CA). AAVSO data show that during the 2016 fading episode it was as faint as CV = 15.6. FO Aqr's brightness in its high state is V~13.4. Coordinates (2000.0): R.A. 22 17 55.38 Dec. -08 21 03.8 Charts: Charts for FO Aqr with an expanded comparison star sequence may be created using the AAVSO Variable Star Plotter (VSP). For observers who have been following FO Aqr as part of the CBA program, the comparison stars used for that program have been retained. Please submit observations to the AAVSO International Database using the name FO AQR. This observing campaign is being followed on the AAVSO Campaigns and Observing Reports online forum at https://www.aavso.org/fo-aqr-campaign This AAVSO Alert Notice was compiled by Elizabeth O. Waagen. AAVSO Alert Notice 597 GW Lib time set for third HST observation September 6, 2017: Further to AAVSO Alert Notices 591, 595, and 596, Dr. Boris Gaensicke (Warwick University) informs us that the date and time for the third and final of three HST observations in his campaign on the pulsating white dwarf-containing cataclysmic variable GW Lib has been scheduled for2017 Sep 13 23:52:02 to Sep 14 04:30:12 UT. Nightly snapshots are requested now through September 9, and intensive monitoring September 10 through 15, then nightly snapshots again through September 21. Dr. Gaensicke reminds observers that the HST scheduling team will "...insist on a last quiescent measurement [V or positive visual] within 24h of the beginning of the COS observations, i.e. after UT Sep 12, 2017, 23:52." As reported before, for the HST observations, AAVSO observations are essential to know the state of the system in order to ensure that the object is NOT in outburst when observed with HST. AAVSO observations made within 24 hours before each HST observing time will be used to make a go/no-go decision; data will be used in the analysis of the resulting data. In addition to uploading observations to the AAVSO database, Dr. Gaensicke requests that all observations be sent to him by email at: boris.gaensicke@gmail.com Coordinates: RA: 15 19 55.45 Dec: -25 00 25.30 (J2000.0) This target is increasingly challenging at this time of year, and your efforts are truly appreciated and are crucial to the HST observations. GW Lib is faint at quiescence, magnitude ~16.8 visual/unfiltered. If visual observers are unable to detect GW Lib, please report any "fainter-than" estimates using the magnitude of the faintest comparison star magnitude seen. CCD observers are asked to use filters during observations if available; V filter is preferred, but B, Rc, and Ic may also be used. Detection of the variable itself is not required unless you can reach V=16.8 in reasonable time, but please use sufficient exposure to detect at least the V=143 comparison star (RA 15:19:39.54 Dec. -25:00:31.8) or V=147 (RA 15:20:01.73 Dec. -24:58:37.7) with a S/N of 10 and report the observation as a "fainter-than" observation. GW Lib may be as bright as V=8.2 in outburst. Beginning now, please observe this object as often as possible according to the schedule and using the observing procedure outlined above, and submit data as soon as possible to the AAVSO International Database using the name GW LIB. During the nights of intensive observations as indicated above, prompt submission of your observations will be critical. In the event of an outburst, please contact the AAVSO immediately. Charts with a comparison star sequence for GW Lib may be plotted using the AAVSO Variable Star Plotter (VSP). This observing campaign is being followed on the AAVSO Campaigns and Observing Reports online forum at https://www.aavso.org/gw-lib-k2-hst-observations Thank you for your observing efforts and valuable observations! This AAVSO Alert Notice was prepared by Elizabeth O. Waagen. AAVSO Alert Notice 588 Long-term CCD monitoring of ER UMa-type variable DDE 48 in Vulpecula July 21, 2017: The following request for AAVSO assistance has been received from Denis Denisenko (Sternberg Astronomical Institute, Moscow State University) to help characterize "...the cataclysmic variable DDE 48 in Vulpecula. This CV belongs to the rare ER UMa subtype of dwarf novae, with only 6 other stars in VSX being classified as UGER. According to 2016- 2017 observations by Nikolay Mishevskiy (MNIC) and Denis Denisenko (DDE), this variable is very active, with superoutbursts to magnitude V=15.4 occurring approximately once a month. There are several normal outbursts between the superoutbursts. "The campaign has two goals: 1) to study the long-term behaviour (that is, determine the supercycle length and the exact number of normal outbursts per supercycle); 2) to measure the orbital period and to follow the evolution of superhumps period during the superoutbursts. "Snapshot photometry (preferrably 2-3 times per night) is requested beginning now until the next superoutburst, which is about to start within the next 2-3 days. Observations from different longitudes are essential since the variable is changing very rapidly. When DDE 48 brightens to magnitude V=16, continuous time series are requested for as long as possible while the object is above 30 deg elevation." DDE 48 is V=19.0-19.5 at minimum. "Unfiltered observations are OK when the variable is below magnitude V=16. Use V filter only if you can reach S/N ratio of at least 50 in 60-sec or 90-sec exposures. "Charts with a comparison star sequence for DDE 48 may be created using the AAVSO Variable Star Plotter (VSP). The recommended comparison star is the 146 on the AAVSO chart (V=14.573) and is located 3 arc min east of DDE 48, and the check star is the 156 (V=15.605), which is 2 arc min east of DDE 48." DDE 48 entry in AAVSO VSX: Coordinates: 20 46 11.80 +24 20 57.2 (J2000.0) "Note: DDE 48 is located only 4 arc minutes west of another dwarf nova, MASTER OT J204627.96+242218.0, which has outbursts to V=15.5. Please take the opportunity to investigate these two poorly studied cataclysmic variables in one CCD field of view. The same comparison stars can be used for both CVs. "A color-combined DSS finder chart showing the position of DDE 48 and MASTER OT J204627.96+242218.0 (10'x10' FOV) may be seen at: Please report your observations to AAVSO International Database using the name DDE 48. This campaign, which will run through October 2017, is being monitored on the AAVSO Observing Campaigns webpage and is being followed on the Campaigns and Observation Reports Forum at https://www.aavso.org/dde-48-observing-campaign. This AAVSO Alert Notice was compiled by Elizabeth O. Waagen from text supplied by Denis Denisenko. | Last updated 11:32 UT on 23 September 2017 New outbursts and unusual activity reported in the last 72 hours YYYYMMDD 20170922 QT Aqr NY Her WY Tri 20170921 AT Cnc SU UMa Current superoutbursts (since ...) WX Hyi (20170918) SY Cap (20170916) V344 Lyr (20170916) NSV 2026 (20170916) KV And (20170915) V1454 Cyg (20170913) ASASSN-17me (20170913; superhump period ~1.5 h) PNV J20205397+2508145 (170912; Psh= 0.056528 d) TCP J20100517+1303006 (201709212) TY PsA (20170908) ASASSN-13dh (20170908; superhump per. 0.09144 d) TCP J231308.1+233702 (20170908) AD Men (20170904) ASASSN-17lr # (20170904; UGWZ:) V521 Peg (20170831; precursor on 20170824) 1RXS J161659.5+620014 (2070831) NN Cam (20170830) ASASSN-15qu (20170830) CRTS J044027.1+023301 (20170830) CTCV J1940-4724 (20170827) MASTER OT J212624.16+253827.2 (20170825) NSV 1440 (20170824; 3rd rebrightening 20170917) ASASSN-17kd (20170729; rebrightening 20170903) TCP J18154219+3515598 (20170602) Z Cam-type dwarf novae at standstill Z Cam (since 20170405) IW And (20170812–20170831, 19 days) OQ Car (20160415–20170826, 498 days) # indicates a noteworthy or unusual outburst : indicates confirmation required 'Activity At A Glance' is gleaned from observations reported to AAVSO MyNewsFlash, BAAVSS-Alert, CVnet-Outburst, VSObs-share and VSNET-outburst. We sincerely thank all the observers who contribute timely observations and reports of activity to these email lists. RECENT PAPERS ON CVs For new papers on CV's see arxiv.org astro-ph Patrick Godon, Edward M. Sion, Solen Balman, William P. Blair Michael M. Shara, Trisha F. Doyle, Ashley Pagnotta, James T. Garland, Tod R. Lauer, David Zurek, Edward A. Baltz, Ariel Goerl, Attay Kovetz, Tamara Machac, Juan Madrid, Joanna Mikolajewska, J. D. Neill, Dina Prialnik, Doug L. Welch, Ofer Yaron J.M Hameury & J.P Lasota V. V. Lukin, K. L. Malanchev, N. I. Shakura, K. A. Postnov, V. M. Chechetkin, V. P. Utrobin Authors: Edward Sion, Patrick Godon, Liam Jones Authors: A. F. Pala, B. T. Gänsicke, D. Townsley, D. Boyd, M. J. Cook, D. De Martino, P. Godon, J. B. Haislip, A. A. Henden, I. Hubeny, K. M. Ivarsen, S. Kafka, C. Knigge, A. P. LaCluyze, K. S. Long, T. R. Marsh, B. Monard, J. P. Moore, G. Myers, P. Nelson, D. Nogami, R. Pickard, G. Poyner, D. E. Reichart, D. Rodriguez Perez, M. R. Schreiber, J. Shears, E. M. Sion, R. Stubbings, P. Szkody, M. Zorotovic Liam K Hardy, Martin J McAllister, Vik S Dhillon, Stuart P Littlefair, Madelon C P Bours, Elme Breedt, Tim Butterley, Anurak Chakpor, Puji Irawati, Paul Kerry, Tom R Marsh, Steven G Parsons, Chris D J Savoury, Richard W Wilson, Patrick A Woudt Authors: T. Muñoz-Darias, J. Casares, D. Mata Sánchez, R. P. Fender, M. Armas Padilla, K. Mooley, L. Hardy, P. A. Charles, G. Ponti, S. E. Motta, V. S. Dhillon, P. Gandhi, F. Jiménez-Ibarra, T. Butterley, S. Carey, K. J. B. Grainge, J. Hickish, S. P. Littlefair, Y. C. Perrott, N. Razavi-Ghods, C. Rumsey, A. M. M. Scaife, P. F. Scott, D. J. Titterington, R. W. Wilson Authors: Rod Stubbings, Mike Simonsen Authors: Artur Rutkowski, Waclaw Waniak, George W. Preston, Wojciech Pych Authors: Andrey Semena, Mikhail Revnivtsev, David Buckley, Alexander Lutovinov, Hannes Breytenbach Author: Thomas E. Harrison Authors: Michael M. Shara, Laurent Drissen, Thomas Martin, Alexandre Alarie Authors: T. Kato et al Authors: T.V. Tomov, K.A. Stoyanov, R.K. Zamanov |
