NNo GCVS J2000.0 Type Max Min I Min II Epoch Year Period M-m/D Spectrum References Other desig. p.m.(as/yr) Epoch Ident. New type GCVS
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710171 |FG Sge *|201156.06 +202004.4 |* | 9.45 | 13.6 | |B | | | | |B4Ieq-K2Ib |09717 05665| |+0.000 -0.009|2000.0 | |Hip | |FG Sge |
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_______________Cross-identifications:_______________
FG Sge = AN 1943.0377 |
FG Sge = GSC 01626.00619 |
FG Sge = He 2-457 |
FG Sge = He 3-1844 |
FG Sge = Hip 099527 |
FG Sge = IRAS 20097+2010 |
FG Sge = S 03702 |
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Reference to a chart or photograph:05665. G.H. Herbig, A.A.Boyarchuk, ApJ 153, 397, 1968 {1968ApJ...153..397H}
Reference to a study of the star:
09717. V.P.Arkhipova, Perem Zvezdy 21, N5, 617, 1982.
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Remark:
VB A (B 14.2m, 8", 100deg). The central star of the
planetry nebula PK 60deg (diameter 36", the age about 6000
years). The brightness of the star steadily increased from
13.6 pg in 1894 to the maximum in 1967, and then is
steadily decreasing. In 1982 it was 11.0 B. In 1967 the
strong absorption lines of rare earth elements appeared
in the spectrum. The spectral class steadily becomes
later. The signes of new planetary nebula ejection were
observed. In 1962 the star entered the instability
strip in the Mv, B-V diagram and began to pulsate
with a small amplitude and increasing period: Min(V) =
2442629 + 59.83d*E + 1.126d*E**2 (JD2442600 - 44530).
In twenty years the period increased from 50d to 134d,
the amplitude of pulsations changed from 0.2mV to 0.5mV;
now it decreased again to 0.2mV, and the period is only
90d [09780].
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