Galactic clusters and H II regions

Becker, W.; Fenkart, R.

doi:10.1017/s0074180900000553

Cited by 17 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fact that young open clusters are tracers of the spiral structure has been known for several decades (eg. Becker & Fenkart, 1970). The distribution of open clusters in the Galactic disk is shown in Figure 1, for clusters younger than 7 Myr, and in Figure 2, for clusters older than 30 Myr .…”

Section: Basic Assumptionsmentioning

confidence: 99%

Direct Determination of the Spiral Pattern Rotation Speed of the Galaxy

Dias

Lépine

2005

ApJ

159

165

View full text Add to dashboard Cite

The rotation velocity of the spiral pattern of the Galaxy is determined by direct observation of the birthplaces of open clusters of stars in the galactic disk as a function of their age. Our measurement does not depend on any specific model of the spiral structure, like the existence of a given number of spiral arms, or the presence of a bar in the central regions. This study became possible due to the recent completion of a large database on open clusters by our group. The birthplaces of the clusters are determined by two methods, one that assumes that the orbits are circular, and the other by integrating the orbits in the Galactic potential for a time equal to the age of the clusters. We selected in the database a sample of 212 clusters for which proper motions, radial velocities, distances and ages are available, or of 612 clusters that have ages and distances available. We tested different assumptions concerning the rotation curve and the radius R 0 of the solar orbit. Our results confirm that a dominant fraction of the open clusters are formed in spiral arms, and that the spiral arms rotate like a rigid body, as predicted by the classical theory of spiral waves. We find that the corotation radius R c is close to the solar galactic orbit (R c /R 0 = 1.08 ± 0.08). This proximity has many potentially interesting consequences, like a better preservation of life on the Earth, and a new understanding of the history of star formation in the solar neighborhood, and of the evolution of the abundance of elements in the galactic disk.

show abstract

Section: Basic Assumptionsmentioning

confidence: 99%

Direct Determination of the Spiral Pattern Rotation Speed of the Galaxy

Dias

Lépine

2005

ApJ

159

165

View full text Add to dashboard Cite

show abstract

“…Young open clusters have long been recognised as privileged spiral tracers (Becker & Fenkart 1970). Their distances can be better determined than those of individual stars and their youth keeps them close to the spiral arms where they were born.…”

Section: Introductionmentioning

confidence: 99%

Spiral structure of the third galactic quadrant and the solution to the Canis Major debate

Moitinho

Vazquez

Carraro

et al. 2006

Monthly Notices of the Royal Astronomical Society: Letters

144

View full text Add to dashboard Cite

With the discovery of the Sagittarius dwarf spheroidal, a galaxy caught in the process of merging with the Milky Way, the hunt for other such accretion events has become a very active field of astrophysical research. The identification of a stellar ring‐like structure in Monoceros, spanning more than 100°, and the detection of an overdensity of stars in the direction of the constellation of Canis Major (CMa), apparently associated to the ring, has led to the widespread belief that a second galaxy being cannibalized by the Milky Way had been found. In this scenario, the overdensity would be the remaining core of the disrupted galaxy and the ring would be the tidal debris left behind. However, unlike the Sagittarius dwarf, which is well below the Galactic plane and whose orbit, and thus tidal tail, is nearly perpendicular to the plane of the Milky Way, the putative CMa galaxy and ring are nearly co‐planar with the Galactic disc. This severely complicates the interpretation of observations. In this Letter, we show that our new description of the Milky Way leads to a completely different picture. We argue that the Norma–Cygnus spiral arm defines a distant stellar ring crossing Monoceros and the overdensity is simply a projection effect of looking along the nearby local arm. Our perspective sheds new light on a very poorly known region, the third Galactic quadrant, where CMa is located.

show abstract

“…s (1978) compilation: Radial velocity, distance, colour excess, total apparent magnitude, total absolute magnitude, linear diameter, age, mass Basel data (Becker and Fenkart 1971;Fenkart and Binggeli 1979): Photometric system, colour excess, interstellar extinction, distance, spectral type of hottest star, colour type of bluest star, linear diameter, type of observation van den Bergh-Hagen (1975) data: Angular diameter, richness Lynga (1979) compilation: Selected angular diameter, references (various other parameters with references will be included later).…”

mentioning

confidence: 99%

A Computer Based Catalogue of Open Cluster Data

Lyngå¹,

Lundström²

1980

Symp. - Int. Astron. Union

120

203

View full text Add to dashboard Cite

The catalogue contains data for 1130 galactic clusters. Each cluster has 255 available storage places. Most of these are reserved for positional, descriptional and physical parameters. In the present version the following items are included: –Cluster name, OC1 No. (Alter et al. 1970)–R.A., Dec (1950.0), R.A., Dec. (2000.0), precession for 10 years, galactic longitude, galactic latitude–Data on peculiar stars (Feinstein 1979): Type, number, references–Part of Dixon's (1976) catalogue: POSS chart type, chart No., coordinates for chart centre (R.A., Dec), position on chart, largest published angular diameter, magnitude of brightest star, Trumpler class, nebulosity–Part of Bochum-Strasbourg catalogue (Kluke et al. 1975): Selected angular diameter, distance, magnitude of brightest star, spectral class, total magnitude, colour excess–Buscombefs (1978) compilation: Radial velocity, distance, colour excess, total apparent magnitude, total absolute magnitude, linear diameter, age, mass–Basel data (Becker and Fenkart 1971; Fenkart and Binggeli 1979): Photometric system, colour excess, interstellar extinction, distance, spectral type of hottest star, colour type of bluest star, linear diameter, type of observation–van den Bergh-Hagen (1975) data: Angular diameter, richness–Lyngå (1979) compilation: Selected angular diameter, references (various other parameters with references will be included later).

show abstract

Galactic clusters and H II regions

Cited by 17 publications

References 0 publications

Direct Determination of the Spiral Pattern Rotation Speed of the Galaxy

Direct Determination of the Spiral Pattern Rotation Speed of the Galaxy

Spiral structure of the third galactic quadrant and the solution to the Canis Major debate

A Computer Based Catalogue of Open Cluster Data

Contact Info

Product

Resources

About