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| BD+17°4708 | |
|---|---|
| Name | BD+17°4708 |
| Epoch | J2000 |
| Constellation | Virgo |
| Ra | 14h 35m 29.8s |
| Dec | +17° 00′ 02″ |
| App mag v | 9.47 |
| Spectral type | F8 |
| Parallax | 16.89 |
| Prop motions | −120.24, −110.95 |
BD+17°4708 is a high-proper-motion, metal-poor F-type subdwarf used as a photometric and spectrophotometric standard. The star has been observed by major observatories and surveys, and has appeared in literature connected to stellar astrophysics, stellar evolution, and calibration work for telescopes and instruments.
BD+17°4708 appears in classic and modern catalogs including the Bonner Durchmusterung, the Henry Draper Catalogue, the Hipparcos Catalogue, and the Two Micron All Sky Survey. Historical catalogs such as the Bonner Durchmusterung and the Henry Draper Catalogue intersect with modern compilations like the Hipparcos Catalogue, the Tycho Catalogue, and the SIMBAD database. The star also carries identifiers used in the Sloan Digital Sky Survey, the Gaia mission, the Two Micron All Sky Survey, and the USNO catalogs.
BD+17°4708 is classified among F-type subdwarfs with absolute magnitude consistent with subdwarf sequences studied in the Hertzsprung–Russell diagram, and its fundamental parameters have been derived through model atmosphere fits used by projects similar to the Gaia-ESO Survey and the APOGEE program. Effective temperature estimates relate to methods employed by the Infrared Flux Method that reference bolometric corrections used in the Geneva Stellar Evolution code and the MESA stellar evolution framework. Stellar mass and radius estimates connect to isochrones from the Padova group and the Yonsei–Yale models, while age inferences relate to turnoff ages used by studies of the Galactic halo, the Kepler mission asteroseismic constraints, and the Geneva-Copenhagen Survey.
Spectroscopic analyses of BD+17°4708 have employed high-resolution echelle spectrographs comparable to those on the Keck Observatory, the Very Large Telescope, and the Subaru Telescope, with spectral synthesis codes analogous to MOOG and SME. The chemical abundance pattern shows metal-poor signatures often discussed alongside the results for halo stars in literature involving the Hamburg/ESO Survey, the RAVE survey, and the SEGUE component of the Sloan Digital Sky Survey. Alpha-element and iron-peak ratios are compared in studies linking to nucleosynthesis sites such as Type II supernovae and Type Ia supernovae, with abundance trends cross-referenced against globular cluster analyses like those for M13, M15, and M92 and dwarf spheroidal comparisons such as Sculptor and Fornax.
Proper motion and radial velocity measurements for BD+17°4708 have been combined to compute its Galactic orbit using potentials similar to those in the Besançon Galaxy model and the GalPot framework. Parallax measurements from astrometric missions akin to Hipparcos and Gaia yield a distance estimate employed in work connected to the Local Standard of Rest, the Oort constants, and studies of halo kinematics that reference landmark systems such as the Sagittarius stream, the Gaia Sausage, and the Hercules stream. Its space velocity components are discussed in the context of moving groups and halo substructure investigated by teams behind the RAVE survey, the GALAH survey, and the SDSS collaboration.
Photometric stability for BD+17°4708 has been evaluated using data reduction pipelines and calibration strategies analogous to those used by the Transiting Exoplanet Survey Satellite, the Kepler mission, and ground-based monitoring programs like ASAS and SuperWASP. Chromospheric activity indicators derived from Ca II H and K lines follow procedures similar to those used by the Mount Wilson Observatory HK Project and are compared with magnetic activity cycles studied in the Sun and in stars observed by the Mount Wilson survey and the Lowell Observatory program. No large-amplitude variability comparable to classical pulsators such as RR Lyrae, Cepheids, or Mira variables has been reported; instead, variability constraints are cited in works concerning photometric standard stability for the Hubble Space Telescope, the James Webb Space Telescope, and major ground-based observatories.
BD+17°4708 has been adopted as a calibration star in spectrophotometric and photometric systems, with its role described alongside primary standards used by the Hubble Space Telescope CALSPEC network, the Landolt standard star catalog, and the Sloan Digital Sky Survey photometric calibration. Calibration efforts referencing BD+17°4708 interface with the workflows of instruments such as the Advanced Camera for Surveys, the Wide Field Camera 3, and spectrographs at observatories like the Keck Observatory and the European Southern Observatory. Its use in establishing flux scales is discussed in publications connected to the International Astronomical Union standards, photometric zeropoint determinations, and absolute spectrophotometry campaigns led by institutions including the Space Telescope Science Institute, the European Space Agency, and national observatories.
Category:Stars