[vsnet-alert 15989] Re: Next HST observations: HS2214+2845 (V513 Peg) & OT J213806.6+261957

[Robert J. Modic]

Boris,

Those SDSS u/g/r images OT J213806.6+261957 really make it
clear which one is the CV!

By the way, has anyone ever measured the Johnson/Cousins mags
and colors for the companions of both HS2214+2845 and
OT J213806.6+261957?  Perhaps with a larger scope (ie., WIYN, HST)?
I know that most observers report combined magnitudes for these
stars, but it would be nice to be able to subtract the light of the
companions for a more accurate result.

Bob


----- Original Message ----- 
From: "Boris Gaensicke" <Boris.Gaensicke at warwick.ac.uk>
To: "Brian Skiff" <bas at lowell.edu>
Cc: "Arto Oksanen" <arto.oksanen at jklsirius.fi>; "Robert J. Modic" <robertjmodic at att.net>; "Roger Pickard" <roger.pickard at sky.com>; 
<vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp>; <cba-chat at cbastro.org>; "Stuart P Littlefair" <s.littlefair at sheffield.ac.uk>; "Michael 
J. Cook" <michael.cook at newcastleobservatory.ca>; "Diego Rodriguez" <blazares at yahoo.es>; "Mike Simonsen" <mikesimonsen at aavso.org>; 
<noc_observatory at yahoo.com>; "Fritz Osell" <fritz.osell at noc.edu>
Sent: Monday, July 15, 2013 4:23 PM
Subject: Re: [vsnet-alert 15974] Re: Next HST observations: HS2214+2845 (V513 Peg) & OT J213806.6+261957


> 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.
>> > > >
>>
>>
>>
>>
>>
>