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Re: [vsx-dis] ASAS 183136-1815.4

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  • arne
    ... From MKTypes.dat, the coordinates for SS73 167 = UCAC2 24932494 are: 1973ApJ...185..899S SS73 167 18 31 36.30 -18 15 25.9 U 14.5 V Be I
    Message 1 of 5 , Jun 11, 2007
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      Patrick Wils wrote:
      > ASAS 183136-1815.4 was found to be a Mira type variable with a period of
      > 209 days (range 12.3-<14.3V) by ASAS3.
      > Brian Skiff's MKTypes.dat file of spectral types contains an entry for
      > SS73 167 = UCAC2 24932494 (mag 14.5V), 4.7" from the position of the ASAS
      > star (and the precision of the ASAS coordinates is only 6"). SS73 167 is
      > a Be star (the source is
      > <http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1973ApJ...185..899S>).
      > If this is not a chance alignment, and both stars are thus physically
      > related, and the Be classification is correct, this might be a symbiotic
      > binary. Is anyone interested in investigating this further?
      >
      From MKTypes.dat, the coordinates for SS73 167 = UCAC2 24932494 are:
      1973ApJ...185..899S SS73 167 18 31 36.30 -18 15 25.9 U 14.5 V Be

      I took UBVRI images of this field during my last NOFS observing
      run a couple of weeks ago. This source is present at
      RA (J2000) DEC V B-V V-Rc Rc-Ic V-Ic
      18:31:36.29 -18:15:26.0 15.097 2.636 2.020 2.090 4.125
      and absent on my U-band image (pretty reddened region in Sgr).
      I see no indication that this is a Be star; looks like a typical
      red star to me.

      I've placed 2x2 arcmin images centered on this object at:
      http://www.aavso.org/tmp2/asasi.jpg
      http://www.aavso.org/tmp2/asasr.jpg
      http://www.aavso.org/tmp2/asasv.jpg
      http://www.aavso.org/tmp2/asasb.jpg
      http://www.aavso.org/tmp2/asasu.jpg
      (sorry about the seeing, but it is never great with the 1.0m)

      Sanduleak and Stephenson's coordinates and information are:
      star RA (B1950) DEC p v n type
      167 18:28:40.7 -18:17:40 14.0 12.0 5 Be! new
      where Be! indicates extreme Be-like object, and n is the last
      resolvable hydrogen line in the emission spectrum. Coordinates were
      derived from measures made on the objective prism plates and should
      be reliable to within several seconds of arc.

      Straight precession of the SS coordinates is
      18:31:36.3 -18:15:29

      All in all, it looks like either the SS catalog picked the wrong
      object, or they caught a symbiotic system in outburst; that
      would agree with their estimate of mv=12. Nothing in the field
      is particularly blue.
      Arne
    • Patrick Wils
      ... The mv=12 may correspond to the maximum magnitude of the Mira star as well (see
      Message 2 of 5 , Jun 12, 2007
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        > All in all, it looks like either the SS catalog picked the wrong
        > object, or they caught a symbiotic system in outburst; that
        > would agree with their estimate of mv=12.

        The mv=12 may correspond to the maximum magnitude of the Mira star as well
        (see
        <http://www.astrouw.edu.pl/cgi-gp/asas_plot_raw_all?183136-1815.4,asas3,0,500,0>
        and <http://skydot.lanl.gov/nsvs/star.php?num=16676109&mask=15636>). You
        likely observed the Mira star near minimum, Arne.
        A lot of the Be stars from SS73 have been recovered during other surveys,
        but not this one. There is always a chance of a typo in the catalog
        coordinates of course (and it seems that way here), but what are the odds
        it then corresponds to within 5" of a Mira variable?

        Patrick


        --- arne <arne@...> wrote:

        > Patrick Wils wrote:
        > > ASAS 183136-1815.4 was found to be a Mira type variable with a period
        > of
        > > 209 days (range 12.3-<14.3V) by ASAS3.
        > > Brian Skiff's MKTypes.dat file of spectral types contains an entry for
        > > SS73 167 = UCAC2 24932494 (mag 14.5V), 4.7" from the position of the
        > ASAS
        > > star (and the precision of the ASAS coordinates is only 6"). SS73
        > 167 is
        > > a Be star (the source is
        > >
        > <http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1973ApJ...185..899S>).
        >
        > > If this is not a chance alignment, and both stars are thus physically
        > > related, and the Be classification is correct, this might be a
        > symbiotic
        > > binary. Is anyone interested in investigating this further?
        > >
        > From MKTypes.dat, the coordinates for SS73 167 = UCAC2 24932494 are:
        > 1973ApJ...185..899S SS73 167 18 31 36.30 -18 15 25.9 U
        > 14.5 V Be
        >
        > I took UBVRI images of this field during my last NOFS observing
        > run a couple of weeks ago. This source is present at
        > RA (J2000) DEC V B-V V-Rc Rc-Ic V-Ic
        > 18:31:36.29 -18:15:26.0 15.097 2.636 2.020 2.090 4.125
        > and absent on my U-band image (pretty reddened region in Sgr).
        > I see no indication that this is a Be star; looks like a typical
        > red star to me.
        >
        > I've placed 2x2 arcmin images centered on this object at:
        > http://www.aavso.org/tmp2/asasi.jpg
        > http://www.aavso.org/tmp2/asasr.jpg
        > http://www.aavso.org/tmp2/asasv.jpg
        > http://www.aavso.org/tmp2/asasb.jpg
        > http://www.aavso.org/tmp2/asasu.jpg
        > (sorry about the seeing, but it is never great with the 1.0m)
        >
        > Sanduleak and Stephenson's coordinates and information are:
        > star RA (B1950) DEC p v n type
        > 167 18:28:40.7 -18:17:40 14.0 12.0 5 Be! new
        > where Be! indicates extreme Be-like object, and n is the last
        > resolvable hydrogen line in the emission spectrum. Coordinates were
        > derived from measures made on the objective prism plates and should
        > be reliable to within several seconds of arc.
        >
        > Straight precession of the SS coordinates is
        > 18:31:36.3 -18:15:29
        >
        > All in all, it looks like either the SS catalog picked the wrong
        > object, or they caught a symbiotic system in outburst; that
        > would agree with their estimate of mv=12. Nothing in the field
        > is particularly blue.
        > Arne
        >




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      • arne
        ... You may be correct about the Mira maximum; however, I based my comment on the fact that it was brighter than when I observed it, and showed strong emission
        Message 3 of 5 , Jun 12, 2007
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          Patrick Wils wrote:
          >>All in all, it looks like either the SS catalog picked the wrong
          >>object, or they caught a symbiotic system in outburst; that
          >>would agree with their estimate of mv=12.
          >
          >
          > The mv=12 may correspond to the maximum magnitude of the Mira star as well
          > (see
          > <http://www.astrouw.edu.pl/cgi-gp/asas_plot_raw_all?183136-1815.4,asas3,0,500,0>
          > and <http://skydot.lanl.gov/nsvs/star.php?num=16676109&mask=15636>). You
          > likely observed the Mira star near minimum, Arne.
          > A lot of the Be stars from SS73 have been recovered during other surveys,
          > but not this one. There is always a chance of a typo in the catalog
          > coordinates of course (and it seems that way here), but what are the odds
          > it then corresponds to within 5" of a Mira variable?
          >
          You may be correct about the Mira maximum; however, I based my
          comment on the fact that it was brighter than when I observed it,
          and showed strong emission lines. There is no evidence of strong
          emission in my photometry; for example, Rc seems to be perfectly
          normal.

          I'll ask Ulisse to get a spectrum as a final check.
          Arne
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