[vsnet-chat 477] Munari et al. sequence near YY Her

[bas@lowell.Lowell.Edu (Brian Skiff)]

     In a thoroughgoing summary of new and historical observations of the
symbiotic star YY Herculis, vsnet contributor Ulisse Munari and colleagues
have provided a UBV sequence in the field (Munari et al. 1997, A&A 323, 113).
The stars were observed using the Crimea 1.25-m telescope, but no details
about the standard stars used is given.  (Some of the U-B colors appear to be 
systematically too blue if the B-V's are correct.)  Although a nice chart was
provided for the field, no positions or identifications were given.  These are
shown in the table below.  The first column shows the name assigned in the
sequence by the authors.  The positions were obtained from the GSC (v1.1), or
for the two faintest stars, from the comprehensive USNO A1.0 star catalogue.
     I show a position for YY Her itself, since the coordinates in SIMBAD are
only approximate (although not seriously in error).  The two brightest
sequence stars can be identified in the HDE.  I also give V and B-V derived
from Table 1 of Munari et al.  Using the U-B and B-V colors, I show in lower
case letters and in parens rough "predicted" spectral types for the fainter
stars.
     The photoelectric sequence, by the way, shows that the values used on the
charts by the AFOEV and by the AAVSO are okay for visual use except for the
faintest stars.

\Brian

+++++++++++++++++++++++++++++++++++++++++

Munari et al.'s sequence near YY Herculis

Name       RA  (2000)  Dec        GSC       V    B-V   Remarks

YY Her  18 14 34.2  +20 59 20  1579-0381
A       18 14 19.4  +21 02 50  1579-0482  11.21  0.49  HD 341876, F5
B       18 14 24.9  +21 05 21  1579-0136  11.60  0.47  HD 341875, G0
C       18 14 26.0  +21 01 12  1579-0432  12.06  0.60  (g0v)
D       18 14 18.5  +20 56 46  1579-0364  12.40  0.93  (g8iii)
E       18 14 33.9  +21 01 41  1579-0534  12.42  0.95  (g8iii)
F       18 14 32.8  +20 55 39  1579-0518  12.18  1.03  (k0iii)
G       18 14 26.5  +20 59 29  1579-0279  13.07  0.65  (g2v)
H       18 14 46.7  +21 03 07  1579-0513  12.94  0.68  (g2v)
I       18 14 45.0  +21 00 37  1579-0340  13.13  1.23  (k2iii)
J       18 14 43.3  +21 00 48  1579-0525  13.61  0.94  (g8iii)  
K       18 14 24.5  +21 00 21  1579-0416  13.24  0.87  (k0v)
L       18 14 30.5  +20 57 35             14.17  0.67  (g2v)
M       18 14 38.8  +20 57 51             14.75  0.54  (f8v)

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