First-ever outburst of RX J0459.7+1926: new SU UMa star!

(CCD image by courtesy of Gianluca Masi)

(Light curve by the VSNET collaboration team: Gianluca Masi, Alessia Cassetti, Gordon Garradd, Lew Cook, Taichi Kato, Makoto Uemura

Discovery of superhumps by Gianluca Masi, Alessia Cassetti

Superhumps by Gordon Garradd

Outburst detection

(vsnet-alert 4118)

RX J0459.7+1926 is currently undergoing its first ever recorded outburst (mag 15 on Feb. 5.149 UT).

Coordinates for Tau3 from DWS97: 04:59:44.03 +19:26:22.9 (J2000.0)

Time-resolved photometry and spectroscopy are recommended.


CCD photometry by Gianluca and Alessia: superhumps!

(vsnet-alert 4119)

Dear Colleagues,

we started a CCD run on this star right now. The sky seems good, even with some probability to have fog in the incoming hours.

We wanted to confirm the outburst: the star is around mag 15 on Feb. 05 at 18.45 UT.

Gianluca and Alessia

CBA - Italy

(vsnet-alert 4122)

Dear Colleagues,

We've just finished a 3.3 hours CCD run on this target, using a SBIG ST-7, unfiltered camera and a 28cm, f/3.3 telescope (CBA Italy).

A VERY preliminary analysis shows the following features:

- clear superhumps, with an amplitude of about 0.4, 0.5 magnitudes;
- a superhump period of about 0.07 days (this is a rough estimate, done with our own
We will post a light curve on the Bellatrix Observatory's website as soon as possible.

So, this star is a new member of the SU UMa class.

Gianluca and Alessia

(vsnet-alert 4124)

Congratulations to Patrick Schmeer for his another important discovery, and Gianluca and Alessia for your successful observations! Now it's another "golden time" for us to set up a new VSNET international observing campaign! The campaign promoter is you, Gianluca Masi, and we Kyoto team will surely join soon. We will make a necessary set-up for a web page for presenting the results.

The object was selected as an optical counterpart of the ROSAT source. The optical spectrum suggests a dwarf nova, and was proposed for further monitoring (though only few observations has been reported ...). The quiescent magnitude was reported as 18, but the V-band photometry at the Ouda station set an upper limit of 18.3. A V-band CCD chart was issued as [vsnet 889], as cited below.

Taichi Kato

(vsnet-alert 4125)

Dear colleagues,

Unfiltered CCD photometry at CBA Belgium Observatory, using a 0.35-m = f/6.3 telescope, on February 5/6 2000, has confirmed the outburst of RX = J0459.7+1926. We had a 1.7h observing run on this object, very much = hampered by clouds, which finally covered the entire sky. All FITS = images were PSF reduced and the resulting light curve clearly shows the = presence of a 0.35 mag modulation, which seems to have all = characteristics of a superhump wave. It therefore is most likely that = this object is a new member of the UGSU-type of CV's. Unfortunately, our = observing session was too short to be able to determine a precise = superhump period value.

Further high-speed photometry is highly recommended, to settle further = characteristics of this interesting variable.

Best regards,

Tonny Vanmunster
CBA Belgium Observatory

(vsnet-alert 4126)

Superhump period of RX J0459.7+1926

Dear Colleagues,

The analysis of the time-series CCD photometry provided by Gianluca Masi and Alessia Cassetti has yielded the superhump period of 0.0682 d. This period makes RX J0459.7+1926 one of SU UMa-type dwarf novae with relatively short orbital periods. Further observations are strongly encouraged. The Kyoto team will be observing, weather permitting (getting better).

Gianluca Masi, Alessia Cassetti, Patrick Schmeer, Taichi Kato, Makoto Uemura
On behalf of the VSNET RX J0459.7+1926 team

VSNET light curve (requires Java)

Light curve

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