AAVSO Bulletin 80 for 2017 - Stars with Double Maxima

In AAVSO Bulletin 80 there are two stars that exhibit double maxima:  R Cen and R Nor. These stars therefore have primary and secondary maxima and minima. They are not included in the main Bulletin table. Their predicted dates of maximum and minimum for January 2017 through February 2018 are presented here in list form (JD and Gregorian calendar dates) and in approximation of the main Bulletin table format.

V Boo, a semiregular, has intermittently demonstrated double maxima behavior for a number of years. In 2014 it became too irregular to predict maxima and minima accurately and was omitted from AAVSO Bulletin 78. However, in 2015 V Boo became more regular and was not demonstrating double-maxima behavior, so it was returned to the non-double-maxima stars. Observations of V Boo are strongly encouraged, and with an approximate magnitude range of 7-11, it is accessible to many sizes of binoculars and telescopes.

In the information below, 'I' indicates a primary extremum and 'II' a secondary. For example, MAX(I) in the list and MAX(25-I) in the table both mean a primary maximum, in this case on the 25th of the month in which the date appears. Dates are for 2017 except where indicated 2018.

R CEN   P = 512 days   
2457861 APR 17 MAX(II)
2457988 AUG 22 min(II)
2458113 DEC 25 MAX(I)
no min(I) in 2017

R NOR   P =  507.5 days
2457791 FEB 6 MAX(II)
2458007 SEP 10 min(II)
2458136 JAN 17, 2018 MAX(I)
no min(I) in 2017
 

In the table below, the following fields are given:
Name: name of variable star
Links:
 L - to the AAVSO Light Curve Generator
 X - to the International Variable Star Index (VSX)
 T - to the AAVSO table of published maxima/minima of long period variables
R.A. and Declination: coordinates in J2000.0
Period: in days
Range: average visual magnitude range based on data in the AAVSO International Database
N: number of observations in the AAVSO International Database received during calendar year 2016
JAN-DEC-FEB: January-December 2017, January-February 2018

The number in a given month indicates the date of extremum; MAX indicates Maximum and 
min indicates minimum.  The colors indicate (as chosen by the user) the intervals when 
the star will be brighter than visual magnitude 11.0 or fainter than magnitude 13.5.

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