Abstract
We have performed photometry in B and V of the field of the triple system PSR B1620-26 in the globular cluster M4. Our images were taken with two two-dimensional imaging photon-counting detectors, which permitted deep exposures td be made without saturation. Photometry of the proposed optical counterpart of the second companion of PSR B1620-26 was obtained, yielding a magnitude V=21.30 + - 0.08 and a color B - V = 1.32 + - 0.20. The color index has not been successfully determined previously. These values locate the counterpart on the main sequence of the cluster color-magnitude diagram and lead to a mass determination that is consistent with a 0.48 M. cluster main-sequence star.
| Original language | English (Ireland) |
|---|---|
| Number of pages | 115 |
| Journal | Astrophysical Journal |
| Volume | 473 |
| Publication status | Published - 1 Dec 1996 |
Authors (Note for portal: view the doc link for the full list of authors)
- Authors
- Shearer, A,Butler, R,Redfern, RM,Cullum, M,Danks, AC
- Shearer, A;Butler, R;Redfern, RM;Cullum, M;Danks, AC