Observations of the eclipsing binary b Persei

PTS

Dr. Robert Zavala (USNO-Flagstaff) and collaboratorsrequest observations of the bright variable star b Persei for the next twoweeks, in hopes of catching a predicted eclipse on 2015 January 15 UT.  

This is a follow-up to the February 2013 campaign announcedin Alert Notice 476, and will be used as a photometric comparison for upcominginterferometric observations with the Navy Prototype Optical Interferometer(NPOI) in Arizona.  Observers are askedto obtain time-series observations beginning immediately, with the mostcritical window of coverage being between 2015 January 9 and 2015 January 17UT.

b Persei is located at the following (J2000) coordinates:

               RA:04 18 14.62 , Dec: +50 17 43.7

b Per is a bright star (V=4.598, B-V=0.054) and so isideal for observers with photoelectric photometers or those using DSLRcameras.  

Telescopic CCD observers may also be able to observe bystopping down larger apertures. Time-series observations with a V-filter areideal; other filters may be used, but multicolor photometry is not required.

For photoelectric photometry, we have assigned thefollowing stars as comparison and check:

Comparison star:

               SAO24412, RA: 04 06 35.044 , Dec: +50 21 04.55 ,

                              V=4.285,B-V = -0.013

Check star:

               SAO24512, RA: 04 16 43.087 , Dec: +53 36 42.47 ,

                              V=5.19,B-V = -0.05

DSLR observers may also find the nearby star SAO 39457 /HR 1330 a useful comparison star; it is available via VSP as the "55"comparison (V=5.456, B-V=0.219).

Dr. Zavala sends the following along with his request:

"[W]e wanted to try and involve AAVSO observers in afollow up to our successful detection of the b Persei eclipse of Feb 2013,AAVSO Alert Notice 476 and Special Notice 333.

Our goal now is to get good time resolution photometry asthe third star passes in front of the close ellipsoidal binary. The potentialfor multiple eclipses exists. The close binary has a 1.5 day orbital period,and the eclipsing C component requires about 4 days to pass across the closebinary pair.

For AAVSO observations a single filter would be fine, asour goal is to imporve the timing resolution for the eclipse of the primary,and if possible detect an eclipse of the B component by C. The primary eclipsedepth is 0.15 magnitudes. Photometry to 0.02 or 0.03 mags would be fine todetect this eclipse.

The eclipse prediction date is based on one orbitalperiod from the 2013 eclipse and is:

               JD2457033.79 = 2015 01 11 UT

We'd like to see a baseline light level before and aftereclipse(s) so observing roughly Jan 5-17 would be good. The period for hightime resolution, if possible by AAVSO observers, is Jan 9-13 UT. This predictedeclipse time of minimum light is nominally daylight for the U.S. and we haveabout a +/- 1 day or less uncertainty."

Please promptly submit all observations to the AAVSO viaWebObs using the name "B PER".

This AAVSO Alert Notice was prepared by M. Templeton.