WDS 12357-1650 HJ 1218 AB (HD 109557) : NOTES
 
 
discov_num notes refcode
FIN 368 Aa,Ab: Hipparcos parallax 13.56 +/- 0.76 mas. Dynamical parallax 13.3
mas, masses 1.79 and 1.23 Msun. Speckle measures of 1989-91 and McA1990
2009-11 repeat themselves, hinting at a 20 yr period. However, the Tok2010
measure by Mason et al. in 2006.2 does not fall on the same ellipse Msn2009
and had to be ignored. It could refer to another star, as FIN 368
should have been unresolved at that time according to our preliminary
orbit, which also matches the speckle non-resolution in 1976.3 and the
non-resolutions in 1964-1966 by Finsen. An alternative orbit with P = Fin1965a
10.13 yr and e = 0.9 can also be fitted to the data. The Hipparcos
measure on 1991.25 contradicts speckle interferometry on 1991.39; it HIP1997a
had to be ignored. Nordstrom et al. (1997) noted double lines Nrd1997
broadened by fast axial rotation of 100 km/s and 20 km/s. However,
individual RVs measured by these authors during 1987-1991 (near the
apastron) do not show any systematic behavior that could be related to
the orbit. Continued speckle monitoring will be critical for
confirming the orbit.
 
 
REFERENCES
 
 
refcode metd author reference
Fin1965a J j Finsen, W.S. 1965ROCi..124...79F
Fin1965a Republic Obs. Circ. 124, 79, 1965
HIP1997a Hh - Hipparcos 1997yCat.1239....0E
HIP1997a Hipparcos Catalog, ESA SP-1200, 1997 (incl. Hp photometry, vol. 10)
McA1990 Sc j McAlister, H.A., Hartkopf, & Franz, O.G. 1990AJ.....99..965M
McA1990 AJ 99, 965, 1990
Msn2009 S+ j Mason, B.D., Hartkopf, W.I., Gies, D.R., Henry, T.J., & Helsel, J.W. 2009AJ....137.3358M
Msn2009 +orb AJ 137, 3358, 2009
Msn2009 +lin
Nrd1997 rv - Nordstrom, B., Stefanik, R.P., Latham, D.W., & Andersen, J. 1997A&AS..126...21N
Nrd1997 A&AS 126, 21, 1997
Tok2010 S j Tokovinin, A., Mason, B., & Hartkopf, W. 2010AJ....139..743T
Tok2010 AJ 139, 743, 2010 (some measures corrected in Tok2017b) 2017AJ....154..110T
 
 
DISCOVERER
 
 
idgroup discov author
1 HJ Herschel, J.F.W.
 
 
WDS HISTORIC DATA
 
 
coord_2000 discov_num comp epoch obs pa sep mag_pri mag_sec spectr notes coord_arcsec_2000
12357-1650 HJ 1218 AB 1998 11 260 11.6 6.60 11.00 F4V D 123542.81-164934.1
12357-1650 HJ 1218 AB 2012 12 259 11.9 6.60 11.00 F4V D 123542.81-164934.1
12357-1650 HJ 1218 AB 2014 13 259 11.1 6.60 11.00 F4V NV 123542.81-164934.1
12357-1650 HJ 1218 AB 2015 14 260 11.5 6.74 11.00 F4V NV 123542.81-164934.1

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