Movatterモバイル変換

THE ANTICENTER OF THE GALAXY

THROUGH TAURUS AND AURIGA

Their Clusters, Variables, and Dark Clouds

The Earth andSun are roughly two-thirds of the way from the center of ourGalaxy to a vaguely defined edge. Towards theGalactic Center inSagittarius, theMilky Way is thus broad and thick, while in the otherdirection, 180 degrees away, toward theAnticenter at theborder betweenTaurus and Auriga (whose images are shown below), welook through a far-thinner blanket of stars, rendering the MilkyWay faint and harder to distinguish. Pieces ofGemini,Orion, andPerseus appear around the fringes of theimages.

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

---

TAURUS AND SOUTHERN AURIGA

(North is up and to the left.)

See the:

• full resolutionversion;
• full-resolutionunlabelledimage;
• associated articleThrough Taurus to theAnticenter in the February 2005Sky and Telescope, p.91;
• Cambridge Encyclopediaof Stars.

---

AURIGA

(North is to the left.)

See the:

• full resolutionversion;
• full-resolutionunlabelledimage;

The region around the often-neglected Anticenter (the white "X: ineach of the images) is nevertheless rich inopen clusters (purple circleswith blue labels) andvariablestars (yellow labels). In the image of Taurus, they outline alarge blank area to the left of center, the Taurus-Auriga darkcloud, a complex of dusty molecule-filled star-forming clouds 460light years away that block the light of the more-distantbackground. Two of the open clusters (theHyades andPleiades) arereadily visible to thenaked eye. Inthe Auriga image, the clusters and variables strongly track thefaint Milky Way from upper left to lower right, the dark clouds nowoff to the right.

OPEN CLUSTER PROPERTIES

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

• NAME: Catalogue number (NGC = New General Catalogue; IC = IndexCatalogue) 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 denotevariables 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 exactdefinition, and is meant only as an approximate guide. Ages arealso approximate.

VARIABLE STAR PROPERTIES

• NAME:Variable-star or propername 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 numeralluminosity class;
• MAG:Magnitude range (visual);
• PERIOD: Variable period in days;
• DIST: Distance in light years, where "p," "s," and "c," denotedistances fromparallax,spectral class, and Cepheid period-luminosity relation (allowingfor interstellar absorption);
• REMARKS.

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