Outburst of U Sco

Discovery by Patrick Schmeer

(vsnet-alert 2688)


unless I made a most serious mistake I would say that the recurrent nova is undergoing its first outburst since 1987 - currently at mag 9.5. More later.


Eclipse ephemeris

(vsnet-alert 2690)

U Sco eclipse ephemeris

The detection of the U Sco outburst by P. Schmeer (vsnet-alert 2688, http://www.kusastro.kyoto-u.ac.jp/vsnet/Mail/vsnet-alert/msg02688.html) is one of the most wanted news in the recent decade! Congratulations!!

After the latest outburst in 1987 (whose peak may have been missed), U Sco became recognized as an eclipsing binary (only known one in recurrent novae). The present outburst provides an unique opprortunity in spatially resolving the outbursting recurrent (and very fast, helium-rich, unique) nova. The predicted eclipse times after Schaefer and Ringwald's (ApJ 447, L45) revised ephemeris:

   Min.HJD = 2447717.6061 + 1.2305631 E
                    +/-32       +/-30

  YYMMDD hh:mm:ss (UT)
  990225 01:19:55
  990226 06:51:45
  990227 12:23:35
  990228 17:55:25
  990301 23:27:15
  990303 04:59:05
  990304 10:30:56
  990305 16:02:46
  990306 21:34:36
  990308 03:06:26
  990309 08:38:16
  990310 14:10:06

Time-resolved photometry and spectroscopy around all phases, esp. around predicted eclipses, are most urgently requested. The latest eclipse should have occurred four hours ago; didn't anyone observe around this time?

Considering the cycle count amgibuity (though most seems to have been rejected by Schaefer and Ringwald), observers at other longitudes may have a chance to observe eclipses. Please concentrate on this particular object.

Observers may interested to know significant short-term variability was observed during the 1987 outburst. We indeed (with S. Fujino) observerd by photography, but modern CCD technology will certainly give the answer.

Taichi Kato

Negative observation just preceding ...

(vsnet-alert 2691)


unless I am mistaken...

SCOU 990225.04 <14.3 MLF

I am sorry for ruining the celebrations...


Outburst confirmed!!

(vsnet-alert 2698)

U Sco outburst is confirmed.

Date                        Mag

990225.625            8.0

6" newtonian reflector

Michael Mattiazzo,
Wallaroo, South Australia
(vsnet-alert 2699)

The outburst of U Sco was confirmed on CCD images. The recurrent nova is very bright now. We are just carrying out a time resolved photometry.

Ouda team (K. Matsumoto, T. Kato)


Hipparcos/Tycho-based chart

VSNET light curve (requires Java)

Light curve

VSNET data search


More information

[vsnet-chat 1671] Updated sequence

[vsnet 1777] Selected bright sequence by Granslo

[vsnet 1777] Selected bright sequence by Granslo

[vsnet-alert 2738] Detection of eclipse!

[vsnet-alert 2826] Final fading!

VSOLJ news (in Japanese)

VSOLJ news on U Sco

Granslo's pages and charts

U Sco page

chart mag down to 12.0

chart mag down to 14.5

chart mag down to 17.0

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