BD+63 238 / HR 511

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.)

The Star

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.