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[vsnet-chat 1525] NGC 4414 sequence

Folks,
     The 10 December 1998 issue of the ApJ contains an article by Brad Schaefer
about SN1974G in NGC 4414 (1998 ApJ 509, 80).  The paper is valuable for
collecting in one place much unpublished or obscure data on the event, and for
placing all the photometry on a consistent system.  Included is BV photometry
for comparison stars in the field used in previous publications and on the BAA
and AAVSO charts of the galaxy.  No chart or positions are provided, making the
data difficult to use for other purposes without reference to earlier
publications.  I have made the IDs from those earlier papers using the
USNO-A2.0 star catalogue.  Positions, GSC names, Schaefer's photometry, and a
few spectral types from the literature are shown in the table below, which is
given in order of increasing magnitude.  The columns BAA and AAVSO, taken from
the Schaefer table, show chart magnitudes from those organizations.  A second
AAVSO "148" star is not identifiable via the Schaefer paper; its photometry is
V = 14.87, B-V = 1.47 --- the reddest of the bunch.  Remarks are given for 
three stars with asterisks (*).


Name         BAA AAVSO     RA  (2000)  Dec        GSC       V    B-V   spec
NGC 4414 1*             12 25 38.1  +31 16 43  2528-0325  10.05  0.68  dG5
NGC 4414 2*             12 27 14.1  +31 19 31  2528-0580  10.80  0.73  dG5
NGC 4414 3              12 26 41.1  +31 02 08  2528-0617  11.21  0.90  gK0
NGC 4414 B*             12 25 42.8  +31 07 10  2528-0178  11.48  1.11  dK7
NGC 4414 5   125  122   12 26 44.9  +31 19 05  2528-0367  12.34  0.98  dG8
NGC 4414 4   121  123   12 26 11.6  +31 08 19  2528-0220  12.44  0.68  dG5
NGC 4414 D              12 25 21.5  +31 14 59  2528-0094  12.65  1.00
NGC 4414 E              12 25 33.8  +31 05 12  2528-0557  12.98  0.72
NGC 4414 8   130  131   12 25 55.0  +31 12 38  2528-0241  13.30  0.83
NGC 4414 F              12 25 58.0  +31 01 19  2528-0349  13.59  0.76
NGC 4414 6   137  138   12 26 36.7  +31 22 04  2528-0574  13.93  0.57
NGC 4414 G              12 25 14.0  +31 09 22  2528-0450  13.99  0.62
NGC 4414 7   143  143   12 26 05.1  +31 21 51  2528-0253  14.40  0.51
NGC 4414 9              12 27 09.5  +31 07 50             14.56  0.79
NGC 4414 L   148  148   12 26 28.3  +31 15 23  2528-0663  14.89  1.01
NGC 4414 N   ---  151   12 26 01.1  +31 14 33             15.11  0.74
NGC 4414 11             12 26 56.6  +31 01 20  2528-0589  15.17  0.68
NGC 4414 P              12 26 16.0  +31 10 10  2528-0280  15.40  1.12

Remarks
NGC 4414 1   BD+32 2245.  Tycho photometry:  V = 9.97 +/- 0.03, B-V = 0.71
             +/- 0.04.
NGC 4414 2   slight motion; ACT position for epoch 2000.0.
NGC 4414 B   G 148-57, proper motion -0".34/+0".16 per year; GSC position
             given for epoch 1983.3.  B-V color corresponds to somewhat earlier
             spectral type.


     It turns out several of the stars already have published UBV photometry.
Comparisons for five stars are shown below.  The "BPS" star is from the survey
by Beers, Preston, and Shectman, and the photometry specifically from
Doinidis et al. (1990 PASP 102, 1392 and 103, 973).  The "AKS" stars are from
Andruk et al. (1995 Astron. Nach. 316, 225).  The agreement with Doinidis et
al. is very good; the comparison with Andruk et al. confirms my earlier
conclusion that their data are somewhat noisy but good enough for many
purposes.

Names               V    B-V
BPS BS 16026-30   14.39  0.50
NGC 4414 7        14.40  0.51
		  
[AKS95] 715       12.39  0.72
NGC 4414 4        12.44  0.68
		  
[AKS95] 718       11.21  0.85
NGC 4414 3        11.21  0.90
		  
[AKS95] 719       12.32  0.96
NGC 4414 5        12.34  0.98

[AKS95] 720       10.79  0.71
NGC 4414 2        10.80  0.73


     Schaefer gives relationships to the standard systems for data from various
sources concerning the lightcurve of the supernova.  Those relevant to amateur
observing are:

mb = 0.84mb(Burkholder) + 2.60, and
B = mb - 0.18(B-V) + 0.29

V = mv(BAA) + 0.15

V = mv(AAVSO) + 0.11

where the sources are Burkholder (1995 JAAVSO 23, 127), and the BAA and AAVSO
charts.  These three have rms scatter of +/- 0.07, 0.18, and 0.06 mag.,
respectively.  Schaefer notes there is no significant color term in any of
these older sequences.
     All the new sequence data (except for the large proper-motion star) have
been added to my long list of photometric reference stars at:

http://ftp.lowell.edu/pub/bas/starcats/loneos.stds

All for now.

\Brian

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