[vsnet-id 254] V4074 Sgr

[Taichi Kato <tkato>]

V4074 Sgr

   From the old query in vsnet-chat 522-534:

> Hi,
> 
> I just wish to query the position of V4074 Sgr as shown on the
> new VSNET chart. 
> I have been monitoring this variable for some time, its position
> verified against that shown in the New Years edition 1987 of the
> Duerbeck atlas.   In this case it concerns the 'object' shown on the
> VSNET chart as star 11.50 and not the star indicated as V4074. 
> 
> Perhaps the actual V4074 Sgr position has been reviewed  since
> then (as was its nova classification) , I am in no way to know! 
> Can someone look into it?
> 
> Regards,
> 
> Berto Monard,
> 
> ---
> 
>     I have identified the object using Allen's photographic atlas of
> symbiotic variables.  This identification is truely different from
> Duerbeck's.  The source reference listed in Duerbeck's lacks a finding
> chart.  The position quoted in this reference agrees with Duerbeck's
> position.
> 
>     Interestingly, these two "candidates" for V4074 Sgr are found to be
> listed as peculiar objects.
> 
> Duerbeck's object:
> 
>   181605.50 -305111.5 (2000.0) 11.1  GSC
>   181252 -3052.3 SGRV4074 ZAND 8.6 12.3 P
>   181605.4 -305110 (2000.0) SS1-149 13.0 11.5 7 Z AS295
>   181605.5 -305111 (2000.0) 1150H    Hipparcos
> 
> Allen's object:
> 
>   181612.19 -305208.2 (2000.0) 10.8 N  GSC
>   181612.3 -305208 (2000.0) PK1-6.2
>   181612.5 -305208 (2000.0) ESO457-PN2
>   181612.2 -305207 (2000.0) 1094H    Hipparcos
> 
>   181611.1 -305150 (2000.0) 167362  (emission line star)
> 
> original AS catalog (no finding chart):
> 
>   181250 -3053 (1950.0) AS295
> 
>   Which is the real V4074 Sgr??
> 
> Regards,
> Taichi Kato
> 
> ---
> 
>   I have noticed some more intersting identifications.
> 
> Allen's object:
> 
>   IRAS18129-3053 181257.5 -305312 (1950.0)
> 
> Just midway between Allen's and Duerbeck's:
> 
>   181607.5 -305156 (2000.0) MWC288 11.8 Pec
> 
>   Probably either there exist two emission line stars in this field or
> much confusion.
> 
> Regards,
> Taichi Kato
> 
> ---
> 
>    Actually, "Allen's star" coincides with PK 1-6.2 = SwSt 1 marked in the
> findng chart of Perek and Kohoutek's PN catalogue.  This catalogue classified
> the PN as class I (stellar appearance).  According to Allen's description,
> his finding chart apparently followed Perek and Kohoutek.  However, Allen
> gave his own spectrogram of AS 295B, which apparently shows emission lines
> (including forbidden lines) superimposed on M-type continuum -- apparent
> symbiotic spectrum.  If Allen took his labelled star, it is difficult to
> reconcile with the simple PN interpretation of this star.  Or he mistook
> the finding chart only?
> 
>    In AS catalog, AS 295 was listed as MHalpha 304-41, 2' n.p. HD 167362.
> This description agrees with Duerbeck's identification, but it seems
> a little strange there was no mentioning about the emission-line nature of
> HD 167362.  In Henize's catalog, only the position (18h 09m.6 -30o 54'
> 1900.0) was given for Hen1641.  Again there is no entry for HD 167362,
> though this catalog seems to bear the nature of compilation.
> 
>    Wouldn't it be the fact there is only one emission line star, which
> was at times classified as a planetary nebula, and at times a variable
> (symbiotic) star?
> 
>    Anyway, please avoid using the VSNET chart for V4074 Sgr.  Hipparcos
> stars in this field being almost certainly of peculiar nature, this chart
> would require independent calibration.
> 
> Regards,
> Taichi Kato
> 
> ---
> 
> Hi everyone,
> I thoroughly investigated the position of V4074 Sgr a few years ago, and
> these are my conclusions.
> 
> 1.  There are indeed two emission line objects in the vicinity. V4074 Sgr
> has been known as H-alpha emission line object since 1950. It is 3" due 
> south of a 12th magnitude, normal K0 III star.
>     The other object is HD 167362, a planetary nebula.
> Positions (1950): 
> V4074 Sgr : 18h12m51.9s -30d52'16"
> HD 167362 : 18 12 55    -30 53 10.
> 
> D.A. Allen and Duerbeck agree with their published coordinates, and are
> both, to all intents and purposes, correct.
> 
> Finder Charts:
> Duerbeck's chart is correct, but is hard to follow.
> Allen's chart is wrong. He points to HD 167362, while V4074 Sgr is in fact
> 8.5mm W, 7mm N of the indicated position. His chart is easier on the eye.
> 
> Examining Allen's chart under magnification, the images of V4074 Sgr and
> HD 167362 are very similar, which is no doubt the reason his chart is
> wrongly marked. 
> 
> Regards,
> Mati Morel
> 
> Refs: 
> Duerbeck, H.W.: Space Science Reviews, 45/1+2 (1987)
> Allen, D.A. : Proc. ASA 5(3),369-385 (1984)
> 
> ---
> 
>      You might be correct.  There are often multiple entries for a single
> object in SIMBAD, and it seems as though this field needs checking.
> \Brian
> 
> ---

    Now 2MASS presents additional information:

  First star:

GSC7392.1189 181605.49 -305111.6 (2000.0) 11.02 6
GSC7392.1189 181605.51 -305111.5 (2000.0) 11.25 6
USNO0525.27411778 181605.448 -305112.12 (2000.0) 12.0 12.4 *
2MASS 181605.552 -305112.68 (2000.0)  9.091  7.993  7.738
181605.4 -305111 (2000.0) V4074Sgr 11.5 - ZAND 
181605.4 -305110 (2000.0) SS1-149 13.0 11.5 7 Z AS295
181606.0 -305100 (2000.0) BE(Buscombe) V=6.7 - -
181605.5 -305111 (2000.0) 1150 TYC7392.1189.1
181605.5 -305111 (2000.0) 1150H HIP089526 plx=4.47(7.92)
181605.5 -305113 (2000.0) - TYC7392.1189.2
181605.2 -305114 (2000.0) SGRV4074 * ZAND 8.6 12.3 P - - - R0/DOW

  Second star:

GSC7392.886 181612.19 -305208.4 (2000.0) 10.91 6
GSC7392.886 181612.20 -305208.1 (2000.0) 10.62 6
USNO0525.27432563 181612.191 -305209.10 (2000.0) 99.9 10.9
USNO0525.27432907 181612.303 -305210.57 (2000.0)  9.7 11.1 *
2MASS 181612.336 -305207.68 (2000.0)  0.000  0.000  0.000
181611.1 -305153 (2000.0) CD-30.15469 10.0
181611.7 -305211 (2000.0) CPD-30.5412 10.2
181611.0 -305208 (2000.0) IRAS18129-3053 17.450 86.000 23.850 5.872 0% 2(LRS)
181611.0 -305208 (2000.0) SSC18129-3053 17.450 86.000 23.850 5.872
181612.3 -305208 (2000.0) PK1-6.2
181612.5 -305208 (2000.0) ESO457-PN2
181612.2 -305207 (2000.0) 1094 TYC7392.886.1
181612.2 -305207 (2000.0) 1094H HIP089535 plx=8.93(6.04)

  The first star is "relatively bright" in 2MASS, while the second star
is saturated.  What do you think?

Regards,
Taichi Kato

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