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Possible Nova in Ophiuchus
Dear Colleagues,
Akira Takao (Kitakyushu, Japan) reports the detection of a likely new
object on his two unfiltered CCD images taken on July 10 and 16.
The reality of the object was confirmed on multiple CCD images taken
with different image centers. Takao's observations are summarized
as below (the object's name is tentatively assigned here):
object YYYYMMDD(UT) mag code
OPHnova2003? 20010418.806 <126C Toa.VSOLJ
OPHnova2003? 20020318.808 <116C Toa.VSOLJ
OPHnova2003? 20020512.647 <116C Toa.VSOLJ
OPHnova2003? 20030418.812 <116C Toa.VSOLJ
OPHnova2003? 20030710.598 114C Toa.VSOLJ
OPHnova2003? 20030716.523 112C Toa.VSOLJ
The magnitude were derived from GSC 6833.117, GSC 6833.89, GSC 6833.101.
The instruments were f120mm F4 Telephotolens, ST-8, unfiltered.
Takao reports the approximate position of the object (maximum 20 arcsec
uncertainty) as follows:
17h 19m 14s.4 (J2000.0)
-27o 22' 37"
There is no bright 2MASS star not an IRAS source.
According to ASAS-3 public data, this object was recorded to beighten
on June 20. After maintaining magnitudes of V=11.0-11.5, the object
apparently reached a maximum of V=10.6 on July 1. The corresponding
part is shown below.
HJD-2450000 V error
========================
2805.68946 11.212 0.061 ASAS-3 outburst detection
2809.71132 10.813 0.048
2809.82674 11.340 0.024
2810.63091 11.426 0.088
2810.83013 11.551 0.047
2811.69979 11.452 0.023
2812.63353 11.077 0.047
2812.84579 11.077 0.023
2813.80357 10.902 0.048
2816.83935 10.591 0.022 maximum?
2819.68174 10.799 0.077
2821.58933 10.880 0.039
2833.60945 11.704 0.054
2833.63153 11.647 0.077
2834.72946 11.550 0.042
2836.58633 11.306 0.066
The last ASAS-3 negative detection was about 11 days before this initial
detection, but this negative detection should be treated with caution
because ASAS-3 may have simply failed to pick up the object. Prior to
the present outburst, there was no indication of meaningful detection
by ASAS-3 in the past.
The similarity of the V-band and unfiltered CCD magnitudes indicate
that the object is not a red variable. The light behavior suggests
some sort of an eruptive object such as a nova.
Spectroscopic confirmation as well as precise astrometry is very
urgently requested to reveal the nature of the object.
Regards,
Taichi Kato
Return to the Daisaku
vsnet-adm@kusastro.kyoto-u.ac.jp
