Vulpecula

Vulpecula, being Latin for Fox, is a faint northern constellation located in the middle of the Summer Triangle, an asterism consisting of the bright stars Deneb, Vega and Altair.

Notable features

There are no stars brighter than 4th magnitude in this constellation. The least faint one is Anser (α Vul), a red giant (spectral type M0 III) at a distance of 297 light-years with an apparent magnitude of 4.44. Anser is an optical binary (separation of 413.7") that can be split using binoculars. The second star is 8 Vul.

In 1967, the first pulsar, PSR 1919+21, was discovered in this little constellation by Antony Hewish and Jocelyn Bell, in Cambridge. While they were searching for scintillation of radio signals of quasars, they found a very regular signal consisting of pulses of radiation at a rate of one every few seconds. Terrestrial origin of the signal was ruled out because the time it took the object to reappear was a sidereal day instead of a solar day. This anomaly was finally identified as the signal of a rapidly rotating neutron star. The pulses came (and still come) every 1.3373 seconds – too regular to be associated with any other object. This new object was originally called CP 19191 for "Cambridge Pulsar near RA 19h 19m" and is nowadays called PSR 1919+21 for "PulSaR at RA 19h 19m and DECL +21 degrees".

Notable deep sky objects

Two well known deep sky objects can be found in Vulpecula:

• M27, the Dumbbell Nebula, is a large, bright planetary nebula which was discovered by the French astronomer Charles Messier in 1764 as the very first object of its kind. It can be seen with good binoculars in a dark sky location, appearing as a dimly glowing disk approximately 6 arcminutes in diameter. A telescope reveals its double-lobed shape, similar to that of an hourglass.

• Brocchi's Cluster (Collinder 399) is an asterism formerly thought to be an open cluster. It is also called the Coathanger because of its distinctive star pattern when viewed with binoculars or a low power telescope.

History

In the late 17th century this constellation was created by the Polish astronomer Johannes Hevelius. It was originally known as Vulpecula cum ansere: the Fox and the Goose. The Goose, which was represented in the jaws of the Fox, is no longer officially in the sky but remains in the name of the alpha star: Anser. The name Vulpecula actually means "little fox", the translation "Fox" is more widely used, however.

Mythology

Since it was invented in the 17th century, from faint stars, there is no earlier mythology associated with the constellation Vulpecula.

External Links

• Vulpecula page at SEDS (Students for the Exploration and Development of Space)

• M-27 page at SEDS