Abstract
Relative proper motions have been determined for 1127 stars in the field of the open cluster NGC 188 from plates spanning a 60-year interval, taken with the 76-cm Thaw refractor of the Allegheny Observatory. Special attention has been paid to the corrections for systematic errors as a function of magnitude and color, and to the treatment of membership probabilities for stars with different proper-motion errors. The study is complete to a magnitude B = 16.2. Also some stars brighter than B = 12.5 were eliminated from the study because of the large uncertainty in estimating the magnitude equation at the bright end. The final relative proper motions have an accuracy of 0.5 mas/yr for well-exposed stars. From the cluster membership probabilities based on proper motions we obtain 360 cluster members, enabling us to better define the color-magnitude diagram. We provide a list of highly probable candidate blue stragglers in addition to the sample proposed by Eggen & Sandage (1969). In order to investigate mass segregation, we have analyzed the spatial distribution of the possible blue stragglers. Based on our proper-motion probabilities the spatial cumulative distributions show that the blue stragglers are not more centrally concentrated than the red giants.
| Original language | English |
|---|---|
| Pages (from-to) | 1205-1219 |
| Number of pages | 15 |
| Journal | Astronomical Journal |
| Volume | 111 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 1996 Mar 1 |
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
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A proper-motion membership study of the old open cluster NGC 188. / Dinescu, Dana I.; Girard, Terrence M.; Van Altena, William F.; Yang, Ting Gao; Lee, Young Wook.
In: Astronomical Journal, Vol. 111, No. 3, 01.03.1996, p. 1205-1219.Research output: Contribution to journal › Article
TY - JOUR
T1 - A proper-motion membership study of the old open cluster NGC 188
AU - Dinescu, Dana I.
AU - Girard, Terrence M.
AU - Van Altena, William F.
AU - Yang, Ting Gao
AU - Lee, Young Wook
PY - 1996/3/1
Y1 - 1996/3/1
N2 - Relative proper motions have been determined for 1127 stars in the field of the open cluster NGC 188 from plates spanning a 60-year interval, taken with the 76-cm Thaw refractor of the Allegheny Observatory. Special attention has been paid to the corrections for systematic errors as a function of magnitude and color, and to the treatment of membership probabilities for stars with different proper-motion errors. The study is complete to a magnitude B = 16.2. Also some stars brighter than B = 12.5 were eliminated from the study because of the large uncertainty in estimating the magnitude equation at the bright end. The final relative proper motions have an accuracy of 0.5 mas/yr for well-exposed stars. From the cluster membership probabilities based on proper motions we obtain 360 cluster members, enabling us to better define the color-magnitude diagram. We provide a list of highly probable candidate blue stragglers in addition to the sample proposed by Eggen & Sandage (1969). In order to investigate mass segregation, we have analyzed the spatial distribution of the possible blue stragglers. Based on our proper-motion probabilities the spatial cumulative distributions show that the blue stragglers are not more centrally concentrated than the red giants.
AB - Relative proper motions have been determined for 1127 stars in the field of the open cluster NGC 188 from plates spanning a 60-year interval, taken with the 76-cm Thaw refractor of the Allegheny Observatory. Special attention has been paid to the corrections for systematic errors as a function of magnitude and color, and to the treatment of membership probabilities for stars with different proper-motion errors. The study is complete to a magnitude B = 16.2. Also some stars brighter than B = 12.5 were eliminated from the study because of the large uncertainty in estimating the magnitude equation at the bright end. The final relative proper motions have an accuracy of 0.5 mas/yr for well-exposed stars. From the cluster membership probabilities based on proper motions we obtain 360 cluster members, enabling us to better define the color-magnitude diagram. We provide a list of highly probable candidate blue stragglers in addition to the sample proposed by Eggen & Sandage (1969). In order to investigate mass segregation, we have analyzed the spatial distribution of the possible blue stragglers. Based on our proper-motion probabilities the spatial cumulative distributions show that the blue stragglers are not more centrally concentrated than the red giants.
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U2 - 10.1086/117866
DO - 10.1086/117866
M3 - Article
AN - SCOPUS:0043125162
VL - 111
SP - 1205
EP - 1219
JO - Astronomical Journal
JF - Astronomical Journal
SN - 0004-6256
IS - 3
ER -