THE ANTICENTER OF THE GALAXY

THROUGH TAURUS AND AURIGA

Their Clusters, Variables, and Dark Clouds

The Earth and Sun are roughly two- thirds of the way from the center of our Galaxy to a vaguely defined edge. Towards the Galactic Center in Sagittarius, the Milky Way is thus broad and thick, while in the other direction, 180 degrees away, toward the Anticenter at the border between Taurus and Auriga (whose images are shown below), we look through a far-thinner blanket of stars, rendering the Milky Way faint and harder to distinguish. Pieces of Gemini, Orion, and Perseus appear around the fringes of the images.

Compare with the view of the Galactic Center and its Messier objects.

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TAURUS AND SOUTHERN AURIGA

(North is up and to the left.)

See the:

• full resolution version;
• full-resolution unlabelled image;
• associated article Through Taurus to the Anticenter in the February 2005 Sky and Telescope, p. 91;
• Cambridge Encyclopedia of Stars.

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AURIGA

(North is to the left.)

See the:

• full resolution version;
• full-resolution unlabelled image;

The region around the often-neglected Anticenter (the white "X: in each of the images) is nevertheless rich in open clusters (purple circles with blue labels) and variable stars (yellow labels). In the image of Taurus, they outline a large blank area to the left of center, the Taurus-Auriga dark cloud, a complex of dusty molecule-filled star-forming clouds 460 light years away that block the light of the more-distant background. Two of the open clusters (the Hyades and Pleiades) are readily visible to the naked eye. In the Auriga image, the clusters and variables strongly track the faint Milky Way from upper left to lower right, the dark clouds now off to the right.

OPEN CLUSTER PROPERTIES

The following table gives the properties of the open clusters identified in the above images. In horizontal order the table presents:

• NAME: Catalogue number (NGC = New General Catalogue; IC = Index Catalogue) or popular name;
• MESS: Messier number from the catalogue of Charles Messier;
• CONST: Constellation of residence;
• DIST: Distance in light years;
• ABS: Interstellar dust absorption in visual magnitudes;
• DIAM (min): Diameter in minutes of arc;
• DIAM (ly): Diameter in light years;
• AGE: Age in millions of years;
• REMARKS.

• Single (*) and double (**) asterisks in the NAME column denote variables respectively visible only on the Taurus or Auriga images. Others are seen in both.
• Clusters fall away gradually to an ill-defined fuzzy "edge." Cluster "diameter" thus depends on exposure time and the exact definition, and is meant only as an approximate guide. Ages are also approximate.

VARIABLE STAR PROPERTIES

• NAME: Variable-star or proper name in traditional order;
• VAR CLASS: Variable star class, whether:
  • eclipsing binary;
  • Mira (long-period) variable;
  • semi-regular variable;
  • irregular variable
  • Cepheid variable;
  • RV Tauri star (low-mass pulsators related to Cepheids)
  • Beta Cephei star;
  • Delta Scuti star;
  • Alpha-2 Canum Venaticorum star (magnetic variable).
• SPECT CLASS: Spectral class, including the Roman numeral luminosity class;
• MAG: Magnitude range (visual);
• PERIOD: Variable period in days;
• DIST: Distance in light years, where "p," "s," and "c," denote distances from parallax, spectral class, and Cepheid period-luminosity relation (allowing for interstellar absorption);
• REMARKS.

• Distances from spectral class are very uncertain;
• Single (*) and double (**) asterisks in the NAME column denote variables respectively visible only on the Taurus or Auriga images. Others are seen in both.