[vsnet-alert 15988] Re: Next HST observations: HS2214+2845 (V513 Peg) & OT J213806.6+261957

[Boris Gaensicke]

Dear Brian,

thanks for bringing this up - I forgot to mention that,
indeed, HS2214+2845 also has a relatively nearby
visual companion, but it should be possible to resolve
these two.

I got SDSS u/g/r images of OT J213806.6+261957,
which illustrate that the CV dominates at short
wavelengths,

http://deneb.astro.warwick.ac.uk/phsdaj/Upload/otj2138.jpg

(North up, East left). Arne Henden got the following
coordinates for the two stars from those images,

CV: 21:38:06.694 +26:19:56.91
companion: 21:38:06.546 +26:19:58.37

In the UV, where HST will be observing, the visual
companion will be invisible.

Cheers,

Boris



On 13 July 2013 22:01, Brian Skiff <bas at lowell.edu> wrote:

>      Robert Modic has kindly pointed a further mix-up,
> and I should have been more specific about which star
> I was referring to in my original note.  Briefly, the
> first message was correct after all, and refers to
> OT J213806.6+261957, _not_ to HS 2214+2845 = V513 Peg.
> The latter is the star Arto was thinking I was writing about.
>
>
> ---  OT J213806.6+261957 is indeed the moving component
>      presently nearly 3" southeast of a zero-motion
>      field star.  It is relatively very bright on the
>      SDSS u-band image.  Its motion is toward the northeast,
>      heading away from the optical companion.
>
>
> ---  HS 2214+2845 = V513 Peg is the northwestern star of
>      another optical pair.  This time the cv is nearly
>      fixed, while the companion is moving approximately
>      southeast-ward away from the cv.  Astrometry even
>      from recent catalogues makes this obvious:
>
> epoch       theta  rho    source
> 1997.843   163.3   4.77   2MASS
> 2001.525   161.6   4.91   CMC14
> 2008.844   161.0   5.05   SDSS DR9
> 2009.876   160.9   5.07   SDSS DR9
>
>
> Sorry for the communication break-down --- just trying
> to be helpful of course!
>
>
> \Brian
>
>
>
>
> On Sat, 2013-07-13 at 10:37 -0700, Brian Skiff wrote:
> > Arto is correct --- I goofed (for reasons not obvious
> > to me) in making the cv the moving southeastern star of
> > the pair.  A look at the GALEX images, for instance,
> > makes it obvious which star has the strong uv flux.
> >      So indeed the cv is the northwestern star.
> > My apologies for any confusion this may have caused!
>
> >
> >
> > On Sat, 2013-07-13 at 10:29 +0300, Arto Oksanen wrote:
> > > Hi Brian,
> > >
> > > The SE star? Are you sure?  I have been measuring the NW star with 5
> arc
> > > sec radius aperture. The NW star outbursted, not the SE star of the
> close
> > > pair.
> > >
> > > This is the correct identification:
> > >
> http://deneb.astro.warwick.ac.uk/phsdaj/public_html/12870/HS2214+2845.sdss.gif
> > >
> > > arto
> > >
> > >
> > > 2013/7/12 Brian Skiff <bas at lowell.edu>
> > >
> > > >
> > > >
> > > >      For what it's worth, comparison of POSS-I plate-scans
> > > > with recent images clearly show that the cv has modest
> > > > proper motion, and is presently the southeastern of the
> > > > optical pair.  The SDSS DR9 astrometry indicates a
> > > > separation of 2".5 at epoch 2009.8, which is increasing.
> > > >
>
>
>
>
>