HD 70642 / CD-39 4247
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This star is located around 94 light-years from Sol (HIPPARCOS Plx=34.77, e_Plx=0.60 mas), in the southeastern part (8:21:28.1-39:42:19.5, ICRS 2000.0) of Constellation Puppis, the Stern -- east of Naos (Zeta Puppis), southwest of Beta Pyxidis, north of Regor (Gamma2 Velorum), and northwest of Suhail (Lambda Velorum). On July 3, 2003, astronomers announced the discovery of a Jupiter-type planet around this Sun-like star (press release, exoplanets.org, Anglo-Australian Observatory, and Carter et al, 2003, in pdf -- details below). (See an animation of the planetary and potentially habitable zone orbits of the HD 70642 system, with a table of basic orbital and physical characteristics.)
The star was first designated as CD-39 4247 (as in ChView data files) in 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, however, many astronomers refer to this star as HD 70642, as designated in the Henry Draper (1837-82) Catalogue with extension (HDE), a massive photographic stellar spectrum survey carried out by Annie Jump Cannon (1863-1941) and Edward Charles Pickering (1846-1919) from 1911 to 1915 under the sponsorship of a memorial fund created by Henry's wife, Anna Mary Palmer.
Some astronomers have recently classed HD 70642 as a yellow-orange dwarf star of spectral and luminosity type G5 V, but others once thought that it was a more evolved subgiant (Carter et al, 2003, in pdf). The star appears to a mass (1.00 +/- 0.05) similar to Sol, probably a similar diameter, and about 93 percent of Sol's luminosity. On the other hand, HD 70642 appears to be 1.4 times as enriched as Sol with elements heavier than hydrogen ("metallicity"), based on its abundance of iron. The star appears to be photometrically stable, with a chromospherically inferred age of around four billion years (Carter et al, 2003, in pdf). Useful catalogue numbers and designations for this star include: Gl 304, HIP 40952, HD 70642, CD-39 4247, CP(D)-39 2308, SAO 199126, and LTT 3116.
On July 3, 2003, a team of astronomers (including Hugh R. A. Jones, R. Paul Butler, Chris G. Tinney, Geoffrey W. Marcy, Alan J. Penny, Chris McCarthy, Brad Carter, and Debra A. Fischer) announced the discovery of a giant planet around this Sun-like star (press release, exoplanets.org, Anglo-Australian Observatory, and Carter et al, 2003, in pdf. Radial velocity measurements suggest that HD 70642 has a companion "b" with at least 2.0 times Jupiter's mass. It moves around HD 70642 at an average distance of 3.32 AUs (a semi-major axis around the orbital distance of the Main Asteroid Belt in the Solar System) in a highly circular orbit (e=0.05) that takes about 2,199 +/- 400 days (or around 6.02 years) to complete (exoplanets.org). The orbit of an Earth-like planet (with liquid water) around HD 70642 may be centered around 0.97 AUs -- just within the orbital distance of Earth in the Solar System -- with an orbital period of around 350 days. Astronomers would find it very difficult to detect an Earth-type planet in the water zone of this star using present methods. (See an animation of the planetary and potentially habitable zone orbits of the HD 70642 system, with a table of basic orbital and physical characteristics.)
The following table includes all star systems known to be located within 10 light-years (ly), plus more bright stars within 10 to 20 ly, of HD 70642.
|Star System||Spectra &|
|HR 3270||A4-7 IIIm||5.1|
|HR 3421||G1-4 V-IV||6.5|
|HR 3497||G0 Ia-0||8.8|
|CD-42 4577||G5 V||9.1|
|* plus bright stars *||. . .|
|CD-34 4160||G6 V||11|
|CD-31 5719||G2 V||14|
|CD-48 4069||G8 V||18|
|CD-29 5555||G2-4 V-IV||20|
Up-to-date technical summaries on this star can be found at: Jean Schneiders's Extrasolar Planets Encyclopaedia; the HIPPARCOS Catalogue using the VizieR Search Service mirrored from the Centre de Données astronomiques de Strasbourg (CDS); NASA's ADS Abstract Service for the Astrophysics Data System; and the SIMBAD Astronomical Database mirrored from CDS, which may require an account to access.
Representing the Stern, or Poop deck, of the Argo Navis, Puppis is one of the three constellations that once formed the huge constellation Argo Navis (the ship of the Argonauts), whose stars skimmed the southern horizon, or sea, when seen from Greece. In 1763, the Abbé [Abbot] Nicholas Louis de La Caille (1713-1762) divided the Argo Navis into three smaller constellations: Carina (the Keel), Puppis (the Stern), and Vela (the Sail). For more information on stars and other objects in Constellation Puppis, go to Christine Kronberg's Puppis. An illustration is available at David Haworth's Puppis.
For more information about stars including spectral and luminosity class codes, go to ChView's webpage on The Stars of the Milky Way.
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