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[vsnet-campaign-dn 2092] FT Cam outburst
FT Cam outburst
YYYYMMDD(UT) mag observer
20020109.719 <146 (Timo Kinnunen)
20020112.063 <146 (Mike Simonsen)
20020115.848 <151 (Gary Poyner)
20020118.051 <159 (Gary Poyner)
20020120.106 <146 (Mike Simonsen)
20020125.057 <146 (Gary Poyner)
20020202.989 <156 (Maciej Reszelski)
20020204.922 140 (Maciej Reszelski)
20020204.978 138 (Maciej Reszelski)
20020204.995 138 (Maciej Reszelski)
The outburst is a relatively rare one.
See also IBVS 5082, Kato et al.
Excerpt of the discussion:
Astrometry of FT Cam from our outburst images has yielded the J2000.0
position of 03\h 21\m 14\fs 33, +61\deg 05\arcm 26\farcs 3 (based on 13
GSC-ACT stars). This value is pretty close to other reported astrometry
of 03\h 21\m 14\fs 33, +61\deg 05\arcm 26\farcs 0 (Antipin 1999) and
03\h 21\m 14\fs 35, +61\deg 05\arcm 26\farcs 1 (Schmeer 2000a),
but our result is considered as more accurate because we used the ICRS-based
astrometric grid, GSC-ACT. The corresponding USNO A2.0 star (on the
same astrometric grid) has end figures of 14\fs 415, 25\farcs 73, which
is 0\farcs 8 different from the current measurement. The comparison of
DSS 2 plate taken on 1993 December 11 with DSS 1 (epoch 1954.074) further
confirms the noticeable proper motion between them. The observed
proper motion 0\farcs 02 yr$^{-1}$ is relatively large among dwarf novae
(cf. Harrison et al. 2000; Thorstensen 1999). The observed proper
motion suggests that FT Cam is a relatively nearby object, likely located
within 1 kpc from us, corresponding to the maximum trangential velocity of
100 km s$^{-1}$ (for a discussion on velocity dispersions of cataclysmic
variables, see Harrison et al. 2000). The inferred conservative upper
limit $M_V=+4$ mag of the absolute magnitude in outburst is marginally
consistent with known absolute magnitudes of dwarf novae (Warner 1987).
However, many of observed maxima having been fainter than 14.5, the object
may be intrinsically fainter than usual dwarf novae. This possibility may
be strengthened by the low outburst frequency and shortness of outbursts,
which are relatively unusual for dwarf novae, but are more typical for
outbursts of intermediate polars (IPs). Since the accretion disks in IPs
are magnetically truncated, this may explain the low luminosity and short
duration of outbursts. The identification of FT Cam with a relatively
hard ROSAT source 1RXS J032114.1+610535 may be a further support for the
IP interpretation. Further observations in quiescence in order to search
for possible coherent oscillations are encouraged.
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