Vulpecula
| Vulpecula | |
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| |
| Abbreviation | Vul |
| Genitive | Vulpeculae |
| Meaning in English | the Fox |
| Right ascension | 20 h |
| Declination | 25° |
| Visible to latitude | Between 90° and -55° |
| Best visible | September |
| Area - Total | Ranked 54th 278 sq. deg. |
| Stars with apparent magnitude < 3 | None |
| Brightest star - Apparent magnitude | Anser (α Vul) 4.44 |
| Meteor showers | None |
| Bordering constellations |
• Cygnus • Lyra • Hercules • Sagitta • Delphinus • Pegasus |
Vulpecula, the Fox, is a faint northern constellation located in the middle of the Summer Triangle, an asterism consisting of the stars Deneb, Vega and Altair.
| Table of contents |
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2 Notable deep sky objects 3 History 4 External Links |
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 in 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 fast 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 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 remarkable deep sky objects can be found in Vulpecula:
- The Dumbbell Nebula (M27), one of the most observed deep-sky objects, is a huge planetary nebula which can even be seen using good binoculars in which it appears as a dim glowing disk with a diameter of approximately 6 arc minutes (including the faint halo its size is even half that of the Moon). A telescope reveals its double-lobed shape, similar to that of an hourglass. The M27 was discovered by the French astronomer Charles Messier in 1764 as the very first (and also one of the brightest) of its kind
- Brocchi's Cluster, also called the Coathanger, is an open cluster easily discerned even with the naked eye due to its distinctive star pattern.
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 reputedly remains in the name of the alpha star: Anser. The name Vulpecula actually means little fox, the translation "Fox" is more widely used, however.
External Links
[1] For more information on M-27 see the corresponding page of the web-site of the "Students for the Exploration and Development of Space" (SEDS).
