Coverage of V5668 Sgr (Nova Sgr 2015 No. 2) requested

[PTS]

AAVSO Alert Notice 533
October 30, 2015

Coverage of V5668 Sgr (Nova Sgr 2015 No. 2) requested in support
of HST spectroscopy


Dr. Peter Kuin (Mullard Space Science Laboratory, University College
London) and colleagues in the Swift Nova group have requested AAVSO
observers' assistance in multicolor monitoring of V5668 Sgr (Nova
Sgr 2015 No. 2, see AAVSO Alert Notices 512, 519) in support of
an upcoming spectroscopic observation with the Hubble Space Telescope
Imaging Spectrograph (STIS).

The purpose of the requested monitoring is two-fold: to know the
brightness of V5668 Sgr at the time of the STIS observation (B
magnitude is most helpful), and to know the nova's optical behavior
prior to the time of observation in order to provide the HST
operators with a status report of its brightness 24 hours before
the observation time so they can make a final decision about
approving the observations. If the nova re-brightens by about a
magnitude, it could well be too bright for STIS and the
observations would be cancelled. Thus, your observations are
crucial.

Dr. Kuin writes: "We hope that the [STIS] high resolution spectrum
will help determine the abundances and velocities of the different
atomic and ionic species in the nova ejecta, and learn that way
something new about the dust formation...this one observation is of
sufficiently high spectral resolution that it complements what we
(the Swift nova group) already have very nicely."

The STIS observation will be carried out on 2015 November 6 around
01 hour UT. Beginning immediately, observers are requested to
observe V5668 Sgr in B, V, and SDSS g' bands. Because the spectra
will be taken in the UV and far UV regions, the bluer the monitoring
band, the better; B photometry will be particularly valuable. Visual
observations are also welcome. Nightly observations are requested
through November 13; time series observations are not necessary.

Coordinates: R.A. 18 36 56.84 Dec. -28 55 39.8 (2000.0)

Charts for V5668 Sgr with comparison star sequence may be created
using the AAVSO Variable Star Plotter (VSP, https://www.aavso.org/vsp).

Please submit observations promptly to the AAVSO International
Database using the name "V5668 SGR".


This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

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