Home     Getting Started     To Survive in the Universe    
Inhabited Sky
    News@Sky     Astro Photo     The Collection     Forum     Blog New!     FAQ     Press     Login  

TYC 2538-886-1


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

Bayesian inference of stellar parameters and interstellar extinction using parallaxes and multiband photometry
Astrometric surveys provide the opportunity to measure the absolutemagnitudes of large numbers of stars, but only if the individualline-of-sight extinctions are known. Unfortunately, extinction is highlydegenerate with stellar effective temperature when estimated frombroad-band optical/infrared photometry. To address this problem, Iintroduce a Bayesian method for estimating the intrinsic parameters of astar and its line-of-sight extinction. It uses both photometry andparallaxes in a self-consistent manner in order to provide anon-parametric posterior probability distribution over the parameters.The method makes explicit use of domain knowledge by employing theHertzsprung-Russell Diagram (HRD) to constrain solutions and to ensurethat they respect stellar physics. I first demonstrate this method byusing it to estimate effective temperature and extinction from BVJHKdata for a set of artificially reddened Hipparcos stars, for whichaccurate effective temperatures have been estimated from high-resolutionspectroscopy. Using just the four colours, we see the expected strongdegeneracy (positive correlation) between the temperature andextinction. Introducing the parallax, apparent magnitude and the HRDreduces this degeneracy and improves both the precision (reduces theerror bars) and the accuracy of the parameter estimates, the latter byabout 35 per cent. The resulting accuracy is about 200 K in temperatureand 0.2 mag in extinction. I then apply the method to estimate theseparameters and absolute magnitudes for some 47 000 F, G, K Hipparcosstars which have been cross-matched with Two-Micron All-Sky Survey(2MASS). The method can easily be extended to incorporate the estimationof other parameters, in particular metallicity and surface gravity,making it particularly suitable for the analysis of the 109stars from Gaia.

Dwarf K and M stars of small proper motion found in a large spectroscopic survey
More than 2000 candidates for K and M dwarf status, generally havingproper motions that are either unknown or less than 0.2 arcsec perannum, have been identified in an objective-prism survey covering theentire sky north of declination - 25 degrees and more than 10 degreesfrom the galactic plane. More than 95 percent have no previousindication that they are dwarfs. Several dozen appear to be visualdouble stars.

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:Jagdhunde
Right ascension:13h14m40.15s
Declination:+33°11'28.9"
Apparent magnitude:10.423
Proper motion RA:-19
Proper motion Dec:-3.7
B-T magnitude:12.256
V-T magnitude:10.575

Catalogs and designations:
Proper Names   (Edit)
TYCHO-2 2000TYC 2538-886-1
USNO-A2.0USNO-A2 1200-07043914
HIPHIP 64618

→ Request more catalogs and designations from VizieR