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Special Notice #378: BP Tau Chandra observation times set - time-series observations needed

December 18, 2013: Further to AAVSO Alert Notice 493, Dr. Hans Moritz Guenther (Harvard-Smithsonian Center for Astrophysics) has been given the precise times of the Chandra X-ray observations to be made of the T Tauri star BP Tau:

year:day:hour:min (in UT):
2013:356:22:52-2013:357:10:00 = 2013 Dec 22 22:52 through Dec 23 10:00 UT

2013:359:14:46-2013:360:06:06 = 2013 Dec 25 14:46 through Dec 26 06:06 UT

2013:361:17:58-2013:362:16:18 = 2013 Dec 27 17:58 through Dec 28 16:18 UT

2013:364:08:20-2013:365:12:00 = 2013 Dec 30 08:20 through Dec 31 12:00 UT

2014:002:07:09-2014:003:07:09 = 2014 Jan 02 07:09 through Jan 03 07:09 UT

Time-series observations (multicolor or V) are requested for these windows for correlation with the Chandra observations (one to two observations per night outside of these windows). These high-cadence observations would be extremely valuable and very much appreciated. Regarding the cadence, Dr. Guenther writes: "With X-rays we record the arrival time of every single photon which means that we can decide on the time binning after the observation. Thus, a high cadence would be good, but of course there is an upper limit because it's not a very bright star [~11.3V - ~13.0V]."

Coordinates (2000.0): R.A. 04 19 15.83  Dec. +29 06 26.8

Charts for BP Tau may be created using the AAVSO Variable Star Plotter (VSP, http://www.aavso.org/vsp).

Please report observations as soon as possible to the AAVSO International Database using the name BP TAU.

Many thanks!

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

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