BD+26 2184 / HD 97658
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ę Torben Krogh & Mogens Winther,
(Amtsgymnasiet and EUC Syd Gallery,
student photo used with permission)
BD+26 2184 is an orange-red
dwarf star, like Epsilon Eridani
at left center of meteor. (See a
2MASS Survey image of
BD+26 2184 from the NASA
Star and Exoplanet Database.)
BD+26 2184 is located about 69.5 light-years (ly) away from our Sun, Sol, in the southeastern corner (11:14:33.2+25:42:37.4, ICRS 2000.0) of Constellation Leo Minor, the Lesser Lion, at the border with Constellation Leo, the Lion -- northwest of Zosma (Delta Leonis, Chertan (Theta Leonis), and Denebola (Beta Leonis); northeast of Adhafera (Zeta Leonis), Algieba (Gamma Leonis), and Regulus (Alpha Leonis); southwest of Praecipua (46 Leonis Minoris), 21 Leonis Minoris, and Beta Leonis Minoris); and southeast of Alula Australis (Xi or Ksi Ursae Majoris) and Alula Borealis (Nu Ursae Majoris). On November 1, 2010, a team of astronomers revealed the detection of a super-Earth in a torch orbit with a minimum of 8.2 Earth-masses around BD+26 2184 (Howard et al, 2010 -- more below).
The star is now commonly referred by some astronomers as HD 97658, 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. It was probably first designated as BD+26 2184 in 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 Sch÷nfeld (1828-1891) and Aldalbert KrŘger (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).
|Center of H.Z.?||0.58||0.48||0||...||...||...||...||...||...|
BD+26 2184 is a main-sequence orange-red dwarf star of spectral and luminosity type K1 V -- but was classed as yellow as K0 in the Henry Draper Catalogue (NASA Star and Exoplanet Database). It may have around 85 percent of Sol's mass (Howard et al, 2010, for HD 97658 on Table 1, page 3), 73 percent of its diameter (Howard et al, 2010, for HD 97658 on Table 1, page 3), and 34 percent of its bolometric luminosity (Howard et al, 2010, for HD 97658 on Table 1, page 3; and the NASA Star and Exoplanet Database, derived from the exponential formula of Kenneth R. Lang, 1980). It appears to be 54 to 59 percent as enriched as Sol in elements heavier than hydrogen ("metals") based on its abundance of iron (Howard et al, 2010, for HD 97658 on Table 1, page 3; Raghavan et al, 2010; and Valenti and Fischer, 2005). BD+26 2184 appears to be a chromospherically inactive star (Howard et al, 2010). Useful star catalogue numbers for BD+26 2184 include: GJ 3651 (previously "not numbered" or NN 3651), Hip 54906, HD 97658, SAO 81730, and 2MASS J11143316+2542374.
Estimates provided by the NASA Star and Exoplanet Database -- where the inner edge of BD+26 2184 's habitable zone could be located at around 0.517 AUs from the star and its center around 0.764 AU, while the outer edge lies farther out at around 1.016 AUs -- appear to be somewhat high based on the star's significantly sub-Solar luminosity. Based on its bolometric luminosity (a high estimate from the NASA Star and Exoplanet Database), the distance from BD+26 2184 where an Earth-type planet would be "comfortable" with liquid water is centered around only 0.583 AU -- between the orbital distances of Mercury and Venus in the Solar System. An Earth-type in such a water-zone orbit would probably would have a period of around 176 days or just under half an Earth year.
On November 1, 2010, a team of astronomers working with the NASA-UC Eta-Earth Survey revealed the detection of a super-Earth in a torch orbit with a minimum of 8.2 +- 1.2 Earth-masses around BD+26 2184, using radial-velocity measures from the Keck Observatory's High Resolution Echelle Spectrometer (HIRES). Planet "b" completes an inner orbit around BD+26 2184 in 9.494 +/- 0.995 days at an average orbital distance of 0.0831 +/- 0.0011 AU. Its orbit is assumed to be circular, e ~ 0.0 (Howard et al, 2010, Table 3, page 4).
The following star systems are located within 10 light-years, plus more bright stars within 10 to 20 light-years, of BD+26 2184.
|Star System||Spectra &|
|BD+02 2393||K8 V||9.9|
|* plus bright stars *||. . .|
|BD+36 2162||G0 V||12|
|88 Leonis AB||G0 V |
|40 Leonis||F6 IV||17|
|39 Leonis AB||F8 Vbw |
Up-to-date technical summaries on these stars can be found at: Jean Schneider's Extrasolar Planets Encyclopaedia; the Astronomiches Rechen-Institut at Heidelberg's ARICNS, the NASA Star and Exoplanet Database, and the SIMBAD Astronomical Database. Additional information may be available at Roger Wilcox's Internet Stellar Database.
Constellation Leo represents the Lion that Hercules (also a constellation) had to kill as one of his 12 tasks. Lying between Constellations Ursa Major and Leo, Constellation Leo Minor was created in 1687 by Johannes Hevelius (1611-1687). For more information on the two constellationa and an illustration, go to Christine Kronberg's Leo and Leo Minor. For another illustration, see David Haworth's Leo or Leo Minor.
For more information about stars including spectral and luminosity class codes, go to ChView's webpage on The Stars of the Milky Way.
Note: Thanks to Spike Valance for notifying us of a planet detection around this star.
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