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AAVSO International Database

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.

Alert Notice 587: Observations of FI Vir (Ross 128) needed this week

July 17, 2017: Dr. Abel Méndez (University of Puerto Rico at Arecibo) has requested AAVSO assistance in follow-up observations of the flare star FI Vir (Ross 128) subsequent to his radio observations obtained yesterday (July 16) with the Arecibo and Green Bank (GBT) telescopes and the Allen Telescope Array (ATA).

Special Notice #78: SN 2007oc in NGC 7418A

November 3, 2007: The Central Bureau for Astronomical Telegrams (see CBET 1114) has announced the discovery of supernova SN 2007oc in the southern galaxy NGC 7418A. The galaxy was discovered at magnitude 13.6 on November 3.06 UT (approx JD 2454407.5). The supernova has since been detected on an image taken October 23.09 (approx JD 2454396.6) at magnitude 13.3, and is therefore in its declining phase.

The J2000 coordinates of the supernova are given as

RA: 22 56 41.77    Dec: -36 46 22.3

Special Notice #75: Monitoring of TT Ari in support of MOST observations

October 22, 2007: The Microvariability and Oscillations of Stars (MOST) Satellite will conduct a targeted photometric observing campaign on the cataclysmic variable TT Ari, beginning 2007 October 23 UT (JD 2454397) and concluding on 2007 October 28 (JD 2454402). This observing program was proposed by a group of Austrian amateur astronomers who proposed to the "MOST fuer Alle" program of the University of Vienna, the Austrian partner project of the MOST collaboration's "My Own Space Telescope" program for Canadian observers.

Special Notice #74: Sequence available for SN 2007le

October 17, 2007: Further to AAVSO Special Notice #73, "SN 2007le in NGC 7721", a comparison star sequence has now been added to the AAVSO Variable Star Plotter (VSP). The sequence by A. Henden was obtained at SRO based upon a single night of data; the calibration is estimated to have a zero-point accuracy of approximately 0.03 magnitudes.

Special Notice #73: SN 2007le in NGC 7721

October 15, 2007: SN 2007le was discovered in the galaxy NGC 7721 on October 13, 2007 by L.A.G. (Berto) Monard of Pretoria, South Africa (CBET 1100, Monard). The supernova has since been classified as a type-Ia, approximately 7-10 days prior to maximum (CBET 1101, Silverman et al.).

The coordinates of the supernova are:

RA: 23:38:48.41 , Dec -6:31:21.3 (J2000)

Special Notice #72: 1RXS_J023238.8-371812 rapid fading

October 12, 2007: A new large-amplitude cataclysmic binary, most likely a WZ Sge system, was discovered by K. Malek of the "Pi of the Sky" team in mid-September. It has been linked to the following ROSAT RASS object:

1RXS_J023238.8-371812

and has coordinates of

02:32:38.13 -37:17:54.7     J2000

It was about 11th magnitude upon discovery, and displayed superhumps with period 0.066d.

Special Notice #71: Next HST cataclysmic variable scheduled

October 11, 2007: The next HST object from Paula Szkody's program is scheduled to be observed during the week of October 29 through November 3. This is SDSS J074531.92+453829.5, another cataclysmic variable that is about V=19.1 at quiescence, and unknown brightness in outburst since it has never been observed to outburst. The coordinates are:

07:45:31.92 +45:38:29.5 J2000

and the AAVSO Harvard Designation and name is

0738+45 SDSS074545

Special Notice #70: Brightening of the symbiotic star AG Draconis

October 3, 2007: It was reported in CBET 1091 by U. Munari et al. that the symbiotic star AG Draconis is again in outburst following the decline from its April 2006 bright outburst. They note that the decline apparently halted on 2007 July 07, and has since brightened steadily. Their observations place AG Dra at V = 8.98 on 2007 September 30.8 UT (B = 9.69 and B-V = +0.71). They also note the presence of strong hydrogen and helium emission lines.

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