(cba:news) Fwd: monitoring of SDSS1538 (Joe Patterson) [2018-03-05T23:15:14Z]
Hi CBAers,
Anna has sent this request. The presence of such a hot WD in this
short-period binary is indeed a puzzle, and it's possible we could
contribute to its solution. The estimated magnitude is 18.6, so it's a
daunting challenge for time-series photometry (unless it brightens).
However, some of you probably are able to get decent nightly brightness
estimates - by averaging, long exposures, etc.
I recommend unfiltered since you're likely to need every photon you can
get. Be sure to specify your (primary?) comp star, so she can convert
it to a quasi-calibrated magnitude. But I don't think a real time
series is feasible or even wanted (I'll ask).
joe p
-------- Forwarded Message --------
Subject: monitoring of SDSS1538
Date: Thu, 15 Feb 2018 11:22:33 +0000
From: Pala, Anna <A.F.Pala@xxxxxxxxxxxxx>
To: jop@xxxxxxxxxxxxxxxxxx <jop@xxxxxxxxxxxxxxxxxx>
Dear Joe,
We have been awarded some HST time to observe SDSS J153817.33+512238.0,
a short period CV (Porb = 93.11 min) that hosts an unexpectedly
hot white dwarf (T ~ 30000K). This high temperature could be a clue of a
nova eruption within the past few 1000 years and the HST observations
will help us in identifying possible ashes and the expanding
circumstellar gas shell expected in this case.
The HST scheduling team requires us to provide ground based monitoring
in order to asses the quiescent state of the target prior the HST
observations, which should be scheduled in the window March 27 - April
10.More information on the program can be found at this link:
http://www.stsci.edu/cgi-bin/get-proposal-info?id=15316&observatory=HST
It would be very helpful if the CBA could help us in monitoring this CV.
Would it be possible to release an alert notice about this observations?
To asses the quiescent state we would need nightly V/unfiltered
observations starting on the 23rd of February, a more intense monitoring
in the period March 27 - April 10, and then nightly observations again
through the end of April.
SDSS1538 is a northern target and is quite faint in quiescence:
RA Dec V
15 38 17.3410 +51 23 38.04 18.6
Please, let me know if you need more information.
Thank you very much for your help.
Kind regards,
Anna
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