BD+63 238 / HR 511
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© Torben Krogh & Mogens Winther,
(Amtsgymnasiet and EUC Syd Gallery,
student photo used with permission)
BD+63 238 is an orange-red
dwarf star, like Epsilon Eridani
at left center of meteor. (See
a Digitized Sky Survey image
of BD+63 238 from the
Nearby Stars Database.)
BD+63 238 is located about 32.5 light-years (ly) away from our Sun, Sol, in the part (1:47:44.8+63:51:9.0, ICRS 2000.0) of Constellation Cassiopeia, the Lady of the Chair -- near Segin (Epsilon Cassiopeiae) and M103, northeast of Ruckbah (Delta Cassiopeiae) and the Double Cluster, and east of Navi (Gamma Cassiopeiae). The star may be visible to many Humans without a telescope.
The star's designation as BD+63 238 comes from a catalogue that was originally published in 1863 by Friedrich Wilhelm August Argelander (1799-1875) on the position and brightness of 324,198 stars between +90° and -2° declination that were measured over 11 years from Bonn, Germany with his assistants Eduard Schönfeld (1828-1891) and Aldalbert Krüger (1832-1896). The catalogue became famous as the Bonner Durchmusterung ("Bonn Survey") and is typically abbreviated as BD. It was later expanded and extended during the early 20th Century with the Cordoba (observed from Argentina) then the Cape Photographic Durchmusterung (observed from South Africa).
As a relatively bright star in Earth's night sky, Star A is catalogued as Harvard Revised (HR) 511, 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 -- updated and expanded through the hard work of E. Dorrit Hoffleit and others. HR 511 is also listed as HD 10780 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. (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.)
BD+63 238 is a main-sequence orange-red dwarf star of spectral and luminosity type K0 V. It may have around 92 percent of Sol's mass, 85 percent of its diameter (Johnson and Wright, 1983, page 649), and 46 percent of its luminosity. Deficient in ultraviolet light, the star appears to be 2.3 times as enriched as Sol in elements heavier than hydrogen ("metals") based on its abundance of iron, and BD+63 238's space motion is characteristic of a young disk star (J.B. Hearnshaw, 1974, page 279). Useful star catalogue numbers for BD+63 238 include: HR 511*, Gl 75, Hip 8362, HD 10780, SAO 11983, LHS 1297, LTT 10619, and LFT 162.
BD+63 238 B?
According to the Yale Bright Star Catalogue's notes entry for HR 511, BD+63 238 has an astrometric companion which was unresolved by speckle interferometry.
Hunt for Substellar Companions
The distance from BD+63 238 where an Earth-type planet would be "comfortable" with liquid water is centered around only 0.681 AU. This would be just inside the orbital distance of Venus in the Solar System, where a planet probably would have an orbital period around 213 days or over half of an Earth year. At such a close distance to BD+63 238, astronomers would have great difficulty in detecting such a planet using present methods.
The following star systems are located within 10 light-years of BD+63 238.
|Star System||Spectra &|
|G 244-47||M4 V||0.7|
|Wolf 46 AB||K5 V |
|Wolf 47 AB||M2 Ve |
|AC+60 3496||M2.5 Ve||4.6|
|V547 Cassiopeiae AB||M2.5 V |
|AC+56 13511||M3 Ve||5.5|
|LP 30-55||M V||5.8|
|G 174-14||DC9 /VII||7.1|
|Ross 15||M4 Ve||7.5|
|AC+71 532||M3.5 Ve||7.5|
|BD+74 1047 AabB||K3 V |
|Mu Cassiopeiae AB||G5 VIp |
Up-to-date technical summaries on these stars can be found at: the Astronomiches Rechen-Institut at Heidelberg's ARICNS, and the Nearby Stars Database. Additional information may be available at Roger Wilcox's Internet Stellar Database and at www.alcyone.de's entry for HR 511.
With its stars shaped in a "W," this northern constellation was named by the Ancient Greeks for the mother of Andromeda who claimed to be more beautiful than the daughters of Nereus, a god of the sea. Cassiopeia's vanity so angered the sea god Poseidon that he had Andromeda chained to a rock of the coast as a sacrifice for Cetus (the monstrous whale) until Perseus rescued her. For more information on stars and other objects in this Constellation and a photograph, go to Christine Kronberg's Cassiopeia. For an illustration, see David Haworth's Cassiopeia.
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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