HD 147513 / HR 6094 AB
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The HD 147513 system is located about 42 light-years from Sol, in the southwestern part (16:24:1.3-39:11:34.7, ICRS 2000.0) of Constellation Scorpius, the Scorpion -- east of Eta Lupi, west of the Bug Nebula and Mu1 and Mu2 Scorpii, southwest of Epsilon and Al Niyat (Tau Scorpii), south of Antares (Alpha Scorpii), northeast of Delta Lupi, and northwest of Zeta2, Eta, and Theta Scorpii (Girtab). It is a member of the Ursa Major stellar moving group (Porto de Mello and da Silva, 1997; and Soderblom et al, 1993) and may be visible to some Humans without the aid of binoculars or a telescope. On June 18, 2002, astronomers announced the discovery of a Jupiter-type planet around Sun-like Star A (Observatoire de Genève -- details below). (See an animation of the planetary and potentially habitable zone orbits of the HD 147513 A system, with a table of basic orbital and physical characteristics.) As HD 147513 A has become one of the top 100 target stars for NASA's planned Terrestrial Planet Finder (TPF), images of this star and its position relative to the Milky Way in Earth's night sky are now available from the TPF-C team.
Star A is listed as HD 147513 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. As a relatively bright star in Earth's night sky, Star A is catalogued as Harvard Revised (HR) 6094, a numbering system derived from the 1908 Revised Harvard Photometry catalogue of stars visible to many Humans with the naked eye. The HR system has been preserved through its successor, the Yale Bright Star Catalogue -- revised and expanded through the hard work of E. Dorrit Hoffleit and others.
Star A was probably first observed and listed as CD-38 10983 during 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. (More discussion on star names and catalogue numbers is available from Alan MacRobert at Sky and Telescope and from Professor James B. Kaler's Star Names.)
HD 147513 A is a yellow-range dwarf star of spectral and luminosity type G3-5 V. It has about 92 percent of Sol's mass (press release), 105 percent of its diameter (Johnson and Wright, 1983, page 685), and about 96 percent of its luminosity. The star is only around 300 million years old and about 93 percent as enriched as Sol with iron.
HD 147513 A is a so-called young "Barium dwarf" (s-process element rich but comparatively carbon deficient) star that was probably enriched by an asymptotic branch giant (AGB) star (see Gacrux) but is now a very dim, white dwarf companion, which has an observed separation of around 4,400 AUs -- 5.7' at a HIPPARCOS distance estimate of 42.0 ly (Porto de Mello and da Silva, 1997; and Poveda et al, 1993, pp. 74-75). There is another Barium-dwarf candidate star, Chi1 Orionis or HR 2047 (G0 V), in the same Ursa Major stellar moving group, which suggests that all three stars may have formed a multiple system until their orbital stability was disrupted when the once, brighter and bigger AGB star shed most of an estimated original mass of 2.6 Solar to reveal its white dwarf core about 30 million years ago (Porto de Mello and da Silva, 1997). HD 147513 A is a New Suspected Variable star designated NSV 7680. Useful catalogue numbers and designations for this star include: HR 6094*, Gl 620.1, Hip 80337, HD 147513, CD-38 10983, CP(D)-38 6407, SAO 207622, FK5 3295, and Wo 9559.
On June 18, 2002, a team of astronomers (including Dominique Naef, Francisco Pepe, Michel Mayor, Nuno C. Santos, Didier Queloz, and Stephane Udry) announced the discovery of a giant planet around this Sun-like star (Observatoire de Genève). Radial velocity measurements suggest that HD 147513 has a companion "b" (or "A1") with at least 1.0 times Jupiter's mass. It moves around HD 147513 at an average distance of 1.26 AUs (a semi-major axis just inside the orbital distance of Mars) in a highly eccentric orbit (e=0.52) that takes about 540 days (or 1.48 years) to complete. (See an animation of the planetary and potentially habitable zone orbits of the HD 147513 A system, with a table of basic orbital and physical characteristics.)
The orbit of an Earth-like planet (with liquid water) around HD 147513 A may be centered around 0.98 AUs -- almost the same orbital distance as Earth in the Solar System -- with an orbital period around 370 days (or 1.01 years). However, the orbit of planet b or A1 with an average distance of 1.26 AUs would disrupt the orbital stability of an Earth-type planet in HD 147513 A's water zone. Astronomers are hoping to use NASA's Terrestrial Planet Finder (TPF) and the ESA's Darwin planned groups of observatories to search for a rocky inner planet in the so-called "habitable zone" (HZ) around HD 147513 A. As currently planned, the TPF will include two complementary observatory groups: a visible-light coronagraph to launch around 2014; and a "formation-flying" infrared interferometer to launch before 2020, while Darwin will launch a flotilla of three mid-infrared telescopes and a fourth communications hub beginning in 2015.
H. Bond (STSci), R. Ciardullo (PSU), WFPC2, HST, NASA
HD 147513 B is a young white dwarf (a remnant stellar core which enriched its binary companion, Star A)
with elements heavier than hydrogen when it cast off its outer gas layers) like planetary nebula NGC 2440.
HD 147513 B
Star A is a white dwarf stellar remnant of spectral and luminosity type DA2 /VII. It probably 65 percent of Sol's mass (Gustavo Porto de Mello, 2002; and Porto de Mello and da Silva, 1997), a planet-sized diameter, and less than 0.6 percent of Sol's luminosity. Originally, it may have been a 2.6 Solar-mass star that shed the remainder of its gaseous envelope about 30 million years ago (Porto de Mello and da Silva, 1997; and Holberg et al, 1995). It shares the same common proper motion as Star A and appears to be intermediate in mass and size between Sirius B and 40 Eridani B (Gary Wegner, 1978). Useful catalogue numbers and designations for this star include: Gl620.1 B, Hip 80300, CD-38 10980, CP(D)-38 6406, and EG 274.
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 147513.
|Star System||Spectra &|
|CD-38 11173||K2 V||5.7|
|CD-38 11343||M3 Ve||7.4|
|CD-42 10934||K5 V||7.5|
|L 480-69||M4 V||7.7|
|HR 5864 AB||G6 V-IV |
|* plus bright stars *||. . .|
|Nu2 Lupi||G2 V||12|
|41 Arae 2||G8-K0 V |
|Mu Arae||G3 V-IV||17|
|CD-30 13040||G1-2 V||17|
|HR 5864 AB||F6 V-IV |
|HR 5825||F5 V-IV||17|
|Beta Trianguli Australis A?||F2 IV-III||18|
|DK-26 2485||G6 V||19|
The late John Whatmough created illustrated web pages on this system in Extrasolar Visions.
Up-to-date technical summaries on these stars can be found at: Jean Schneiders's Extrasolar Planets Encyclopaedia; the Astronomiches Rechen-Institut at Heidelberg's ARICNS entry for Star A and Star B, and the Nearby Stars Database. Additional information may be available at Roger Wilcox's Internet Stellar Database.
According to one legend, Orion (the Hunter) boasted that he could kill all the animals which alarmed, Gaea, the Goddess of Earth. Hence, she ordered a giant scorpion to sting Orion to death, which it managed to do at Orion's heel (marked by the star Rigel). For more information on stars and other objects in this Constellation and an illustration, go to Christine Kronberg's Scorpius. For another illustration, see David Haworth's Scorpius.
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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