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Monitoring 1SWASP J162117.36+441254.2 for HST observations

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發表於 2017-2-16 09:02:43 | 顯示全部樓層 |閱讀模式
[size=13.3333px]AAVSO Alert Notice 569

[size=13.3333px]February 15, 2017

[size=13.3333px]Monitoring 1SWASP J162117.36+441254.2 for HST observations


[size=13.3333px]Dr. Elme Breedt (University of Warwick) has requested AAVSO
[size=13.3333px]observers' assistance in monitoring the eclipsing cataclysmic
[size=13.3333px]variable 1SWASP J162117.36+441254.2 (= CSS_J162117.4+441254)
[size=13.3333px]beginning now in support of observations scheduled with the Hubble
[size=13.3333px]Space Telescope for late February - early March.

[size=13.3333px]Dr. Breedt writes: "1SWASP J162117.36+441254.2 (=CSS1621+4412) is
[size=13.3333px]an eclipsing binary star with an orbital period of P = 0.207852 d
[size=13.3333px]= 5 h. It was long thought to be a contact binary from the
[size=13.3333px]double-hump profile of its optical light curve and broad primary
[size=13.3333px]and secondary eclipses, but to our surprise, it went into outburst
[size=13.3333px]in June 2016 (Drake et al. 2016 ATEL#9112). Follow-up observations
[size=13.3333px]by AAVSO observers and others revealed that the object was actually
[size=13.3333px]a cataclysmic variable (Scaringi et al. 2016 ATEL#9114; Thorstensen
[size=13.3333px]et al. 2016 ATEL#9141) with a donor star that is unusually hot for
[size=13.3333px]its orbital period.

[size=13.3333px]"We have now been awarded time on the Hubble Space Telescope, with
[size=13.3333px]which we hope to measure the temperature of the white dwarf in this
[size=13.3333px]binary and to look for signs of nuclear evolution of the hot donor
[size=13.3333px]star.

[size=13.3333px]"During outburst, this CV becomes bright enough that it could
[size=13.3333px]damage the HST detectors, so the AAVSO observations will help to
[size=13.3333px]ensure the safety of the instrument. We would like to monitor the
[size=13.3333px]brightness of the target in the run-up to the HST observations to
[size=13.3333px]ensure that the target is not in outburst and that the HST
[size=13.3333px]observations can be executed safely.

[size=13.3333px]"Please monitor 1SWASP J162117.36+441254.2 once per night (V band
[size=13.3333px]or clear fliter) from the middle of February, increasing to twice
[size=13.3333px]per night in the week before the observations. (At the moment the
[size=13.3333px]HST observations are scheduled for sometime between 27 February -
[size=13.3333px]15 March, but an exact date will be assigned and communicated after
[size=13.3333px]16 February). Please report immediately if the target reaches V=14.5
[size=13.3333px]or brighter, as this would indicate that the target is on the rise
[size=13.3333px]to outburst.

[size=13.3333px]"Time series observations during the HST observation window would
[size=13.3333px]be very welcome as well, if possible. Suggested cadence: 2-3 min."

[size=13.3333px]Observers are requested to begin monitoring this star now and
[size=13.3333px]continue until the end of March 2017. Visual observations are also
[size=13.3333px]welcome. 1SWASP J162117.36+441254.2 is V~15.6 at minimum and can be
[size=13.3333px]as bright as V~13.1 at maximum.

[size=13.3333px]An AAVSO Special Notice will be issued once the exact date of the
[size=13.3333px]HST observations is known. Please be sure you have subscribed both
[size=13.3333px]to the Alert Notices and the Special Notices.

[size=13.3333px]Coordinates for 1SWASP J162117.36+441254.2:
[size=13.3333px]R.A. 16 21 17.36 Dec. +44 12 54.1  (2000.0)

[size=13.3333px]Charts: Charts with a comparison star sequence for
[size=13.3333px]1SWASP J162117.36+441254.2 may be created using the AAVSO Variable
[size=13.3333px]Star Plotter (VSP) at [size=13.3333px]https://www.aavso.org/vsp[size=13.3333px].

[size=13.3333px]Please submit observations to the AAVSO International Database
[size=13.3333px]using the name 1SWASP J162117.36+441254.2. Report observations as
[size=13.3333px]soon after making them as possible, and immediately if the star is
[size=13.3333px]seen going into outburst.

[size=13.3333px]This campaign is being monitored on the AAVSO Observing Campaigns
[size=13.3333px]webpage at [size=13.3333px]https://www.aavso.org/observing-campaigns[size=13.3333px] and is being
[size=13.3333px]followed on the Campaigns and Observation Reports Forum at
[size=13.3333px]https://www.aavso.org/content/1swasp-j162117.36+441254.2-observing-campaign[size=13.3333px].


[size=13.3333px]This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

[size=13.3333px]----------------------------------
[size=13.3333px]SUBMIT OBSERVATIONS TO THE AAVSO

[size=13.3333px]Information on submitting observations to the AAVSO may be found at:
[size=13.3333px]https://www.aavso.org/webobs

[size=13.3333px]ALERT NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION

[size=13.3333px]An Alert Notice archive is available at the following URL:
[size=13.3333px]https://www.aavso.org/alert-notice-archive

[size=13.3333px]Subscribing and Unsubscribing may be done at the following URL:
[size=13.3333px]https://www.aavso.org/observation-notification#alertnotices

[size=13.3333px]-------------------------------------------------
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