Collinder 399
| Collinder 399 / Hangers / Brocchis pile | |
|---|---|
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| Amateur shot of the pile of clothes hangers Cr 399 | |
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Vulpecula |
| Right ascension | 19 h 25 m 24 s |
| declination | + 20 ° 11 ′ 00 ″ |
| Apparent visual brightness | 3.6 likes |
| Angular expansion | 1 ° |
| Number of stars | 10 |
| Brightest star | 4 vulpeculae , 5.2 mag |
| discovery | Al Sufi, 964 |
Collinder 399 ( Cr 399 for short ) or Brocchis cluster is an asterism , an imprecisely defined arrangement of about 10 stars of the 5th to 7th magnitude. Its extension is about 1 °. The brightest star in the cluster is 4 Vul with a brightness of 5.2 mag , the total brightness is about 3.6 mag .
The asterism is in the constellation Fox in the northern sky. The geometric impression of the lighter single stars is the reason for the proper name clothes hanger or heap of clothes hangers . A diffuse spot can be seen with the naked eye , and the characteristic shape can be seen with binoculars or a small telescope.
The group was first mentioned in the literature by Al Sufi in 964 , but is not included in the modern standard Messier , NGC and IC catalogs . Per Collinder added the group to his catalog of open star clusters in 1931 .
The asterism was previously thought to be an open cluster and attempts were made to determine the common distance and movement of the group. The distance of the group was estimated at 300 light years from the solar system , the radial speed was given 18 km / s. The age of the cluster was estimated to be around 200 million years. In the late 1980s, ED Pavlovskaya and AA Filipova studied various star clusters that move together in space. They came to the conclusion that Collinder 399 and about 10 other star clusters form a group. This group includes a. NGC 6633 , NGC 6709 , NGC 6882 , NGC 6885 , IC 4665 , Melotte 20 , Melotte 111 and the Pleiades .
When the astrometry satellite Hipparcos was able to determine the exact distances and movements of the group members, it turned out that a physical connection can be ruled out. Only a few stars are spatially close to one another and the proper motions of these stars also show no significant correlation. The above data on the distance and speed of the cluster relate accordingly only to certain single stars, but are not characteristic of the group. This is also shown in the following table, which lists the ten stars of the group.
| Surname | apparent brightness (V) |
Spectral class | Distance ( Lj ) |
|---|---|---|---|
| HD 182293 | 7.11 | K3IVp | 350 |
| HD 182422 | 6.40 | B9.5V | 1200 |
| HD 182620 | 7.17 | A2V | 580 |
| HD 182761 | 6.30 | A0V | 410 |
| 4 Vul | 5.16 | K0III | 272 |
| 5 vul | 5.59 | A0V | 237 |
| HD 182955 | 5.87 | M0III | 610 |
| HD 182972 | 6.63 | A1V | 1350 |
| HD 183261 | 6.88 | B3II | 2240 |
| 7 Vul | 6.33 | B5Vn | 1160 |
Web links
- Spektrum.de : Amateur recordings [2] [3]
Individual evidence
- ↑ a b c d messier.seds.org
- ↑ Murray Cragin, James Lucyk & Barry Rappaport: The Deep Sky Field Guide to Uranometria 2000.0 . 1st edition. Willmann-Bell, Richmond, VA 1993, ISBN 0-943396-38-7 .
- ↑ Deep-Sky Corner Coathanger Cluster & NGC 6802 [1]
- ↑ Per Collinder: On Structural Properties of Open Galactic Clusters and their Spatial Distribution. Catalog of Open Galactic Clusters . In: Annals of the Observatory of Lund . 2, 1931, pp. B1-B46. bibcode : 1931AnLun ... 2 .... 1C .
- ^ ED Pavlovskaya & AA Filippova: Groups of Open Clusters with Common Motion in the Galaxy . In: Soviet Astronomy . tape 33 , no. 1 , January 1989, pp. 6-10 .
- ↑ H. Baumgardt: The nature of some doubtful open clusters as revealed by HIPPARCOS . In: Astronomy and Astrophysics . tape 340 , 1998, pp. 402-414 .