The Galactic Open Cluster NGC 7419 and Its Five Red Supergiants
Abstract
UBV CCD photometry has been carried out on the heavily reddened (Av = 6.7) Cepheus open cluster NGC 7419. An age of 14 +/- 2 million yr and a distance of 2.3 kpc have been derived using the isochrones of Maeder. The mass function of the cluster satisfies the Salpeter form N(M) is approximately M(-gamma) with gamma = 2.25. The cluster is dynamically relaxed. Radial velocities of the five red supergiants and the six brightest blue stars (mean approximately equals -74 km/s) confirm their membership. However, the radial velocity of the nearby carbon star (MZ Cep) is a factor of 2 too low for it to be a member. There is at most one blue supergiant member; this is much less than the number of red supergiants, in contrast with theoretical predictions. The red supergiants range in type from M2Iab to M7.5I, the coolest (MY Cep) -- an OH/IR source -- being strongly variable in the visible, but not in the IR. The two supergiants cooler than M2 do not fit the theoretical isochrones.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- July 1994
- DOI:
- 10.1086/192051
- Bibcode:
- 1994ApJS...93..187B
- Keywords:
-
- Astronomical Photometry;
- Blue Stars;
- Open Clusters;
- Red Giant Stars;
- Supergiant Stars;
- Cepheus Constellation;
- Color-Magnitude Diagram;
- Radial Velocity;
- Astronomy