CD-51 5974 / Gl 438

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NASA -- larger image

CD-51 5974 may be a dim red dwarf star, like
Gliese 623 A (M2.5V) and B (M5.8Ve) at lower right.
(A Digitized Sky Survey image of CD-51 5974 from
the Nearby Stars Database.)

System Summary

This star is located about 27.4 light-years (ly) away from our Sun, Sol, at the western part of (11:43:14.9-51:49:57, ICRS 2000.0) of Constellation Centaurus, the Centaur -- west of Delta and Rho Centauri and northwest of the Blue Planetary Nebula (NGC 3918) and Gacrux. Its designation as CD-51 5974 came from a visual survey of southern stars begun in 1892 at the Astronomical Observatory of Cordoba in Argentina under the direction of its second director John M. Thome (1843-1908). Thome died before the completion of this southern sky atlas in 1914, when 578,802 stars from declination -22° to -90° were published as the Cordoba Durchmusterung ("Survey"). The "CD" is an extension of an older catalogue by Friedrich Wilhelm August Argelander (1799-1875) in 1863 on the position and brightness of 324,198 stars between +90° and -2° declination that were measured over 11 years from Bonn, Germany, made with his assistants Eduard Schönfeld (1828-1891) and Aldalbert Krüger (1832-1896), which became famous as the Bonner Durchmusterung ("Bonn Survey") abbreviated as BD. The BD and CD were greatly expanded and extended into the modern age of photographic surveys with the subsequent creation of the Cape Photographic Durchmusterung from South Africa.

Today, most astronomers probably refer to this star by its designation of "Gl 438" in the famous Gliese Catalogue of Nearby Stars (CNS, now ARICNS database) of Wilhelm Gliese (1915-93). Gliese was a longtime astronomer at the Astronomiches Rechen-Institut at Heidelberg. He worked there even when it located at Berlin.

The Star

NASA's NStar Database and the SIMBAD Astronomical Database are currently identifying CD-51 5974 as a red dwarf star of spectral and luminosity type M0.0 V, which may be based on Hawley et al (1996, page 2803). However, the Astronomiches Rechen-Institut at Heidelberg's ARICNS still identifies it as a orange-red dwarf star of spectral type K0. The star may even be suspected of being a dim subdwarf (sd/VI) -- like Groombridge 1830 or Kapteyn's Star -- rather than a main-sequence dwarf star (V). In any case, CD-51 5974 may have only around four-tenths of Sol's mass, 39 percent of its diameter (Pasinetti-Fracassini et al, 2001), and about 41/10,000th of its visual luminosity. Useful star catalogue numbers for CD-51 5974 include: Gl 438, CP(D)-51 4413, LHS 2447, LTT 4348, LFT 839, and L 252-28.

Hunt for Substellar Companions

In order to be warmed sufficiently have liquid water at the surface, an Earth-type rocky planet would have to be located very close to such a cool and dim red dwarf star like CD-51 5974. Without accounting for infrared heating, the water-zone orbit would be centered within 0.07 AU -- well within the orbital distance of Mercury. At distance, such a planet would probably be tidally locked -- with one side in perpetual day -- and possibly race around the star in less than 10 days.

Closest Neighbors

The following star systems are located within 10 light-years of CD-51 5974.

Star System	Spectra & Luminosity	Distance (light-years)
CD-51 6859	M3 V	5.8
L 399-68	M3.5 V	6.3
HR 4523 AB	G3-5 V M V	6.3
Hip 54298	?	6.9
L 471-42	M4 V	8.4
L 396-7	M3.5 V	8.9
Hip 50798	?	9.2
CD-31 9113	M2 V	9.8

Other Information

Up-to-date technical summaries on these stars can be found at: the Astronomiches Rechen-Institut at Heidelberg's ARICNS, and NASA's Nearby Stars Database. Additional information may be available at Roger Wilcox's Internet Stellar Database.

Constellation Centaurus cannot be viewed from middle northern latitudes of around 40 degrees, but should become more easily visible to observers that travel south of the equator. For more information about the stars and other objects in this constellation, go to Christine Kronberg's Centaurus. For an illustration, see David Haworth's Centaurus.

For more information about stars including spectral and luminosity class codes, go to ChView's webpage on The Stars of the Milky Way.