[vsnet-chat 2390] Sequence for sn1999em

["Bruce Sumner" <b.sumner@bom.gov.au>]

As promised by Arne Henden, here is the definitive sequence for this 
supernova, based on all sky photometry performed by Arne on one 
photometric night. This sequence is a revision and extension of the 
sequence issued by Berto Monard in vsnet-alert 3658. Visual observers 
should note that the two sequences are the same at the 0.1 magnitude 
level, with the exception of star 11, which is 0.1 magnitude fainter 
in this new sequence.

     SN1999em  (SN)  Range: 13.4  ?
     Position:   04 41 27.15  02 51 45.4 (J2000, from .dat file) 
     Magnitude:  V=13.799  BV=0.113      (from .dat file)

ID    RA  (2000)   DEC       X    Y   N    V      ERR     BV    ERR 

1   04 41 28.3  02 45 22    18  384  1  10.769  0.001   0.414  0.001 
2   04 41 32.5  02 49 42    80  123  1  12.405  0.003   1.202  0.005 
3   04 41 17.2  02 47 47  148  238  1  12.842  0.003   0.713  0.005 
4   04 41 16.9  02 55 30  153 225  1  12.926  0.004   0.734  0.006 
5   04 41 30.1  02 48 07    44  218  2  13.015  0.006   1.157  0.020 
6   04 41 24.5  02 45 53   39  353  2  13.601  0.000   0.875  0.008 
7   04 41 17.4  02 46 49  146  296  2  13.789  0.006   0.841  0.017 
8   04 41 22.4  02 45 36   70  369  2  13.904  0.008   0.720  0.009 
9   04 41 19.1  02 48 03  120  222  2  14.225  0.008   0.722  0.007 
10  04 41 20.0  02 48 06  106  219  2  14.329  0.008   0.663  0.006 
11  04 41 39.7  02 49 39   189  126  1  14.890  0.003   0.795  0.004 
12  04 41 24.8  02 50 36   34   69  1  15.115  0.003   0.614  0.005 
13  04 41 33.2  02 53 32    91 107  1  15.603  0.004   0.609  0.006 
14  04 41 44.6  02 49 36   261  129  1  15.677  0.004   0.671  0.006 
15  04 41 43.9  02 50 00   252  105  1  16.202  0.006   0.918  0.010 
16  04 41 27.5  02 51 44     6    1  1  16.814  0.039   0.513  0.050 
17  04 41 21.6  02 53 03   83  78  1  16.965  0.011   0.618  0.015 

Notes:

Star 16 is a very close companion to the supernova, and may cause 
confusion when the supernova fades into the magnitude 17 range.

The preliminary AAVSO (e) chart for this supernova, dated 11/99, 
contains the sequence from the Thompson & Bryan chart, which is 
based on photoelectric measurements by Alcaino and Liller. As noted 
by Arne a few days ago, there are considerable differences between 
these two sequences:

                   ID   AAVSO  Henden
                          V      V
                    1    112  10.769
                    2    124  12.405
                    4    134  12.926
                    5    130  13.015
                    6    142  13.601
                    7    144  13.789
                    8    138  13.904
                    10   139  14.329
                    11   149  14.890
                    14   156  15.677

Bruce Sumner
5 November 1999

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