BN Monocerotis: an N-Type Variable.
Abstract
Photographic, photovisual, and photo-red observations made with seven different telescopes at the Kirkwood, Lowell, and Harvard observatories are used to study the light and color variation of this N-type variable. Sequences based on polar comparisons are given for the three colors. The photographic light-curve, based on 154 observations, covers an interval of nearly 19 years. It shows a semiregular type of variation with an amplitude of 3 mag. The photovisual light-curve, based on 80 ob- servations, is in phase with the photographic light-curve, but the amplitude is only 1 mag. The p/ioto-re4 light-curve, based on 30 observations, has a stifi smaller amplitude. The variation seems to take place in cycles of 500 days; but smaller fluctuations of shorter period are also present. The color index varies from +4h1t to +6m. It is strongly correlated with the photographic magnitude and only slightly correlated with the photovisual magnitude. The red index varies from +5~5 to +7'~5 and is strongly correlated with the photographic magnitude. There is little or no correlation with the photo-red magnitude.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1944
- DOI:
- 10.1086/144631
- Bibcode:
- 1944ApJ...100....1E