Poчetna     To Survive in the Universe    
Services
    Why to Inhabit     Top Contributors     Астро Фотографије     Колекција     Форум     Blog New!     FAQ(Често постављана питања     Улогуј се  
→ Adopt this star  

HD 24520


Садржај

Слике

Уплоадјуј своје слике

DSS Images   Other Images


Везани чланци

Reddening and the Extinction Law at High Galactic Latitude
We present near-infrared (JHKL) photometry of 103 southern stars locatedbehind translucent interstellar clouds at high Galactic latitude. Ourdata are combined with visual photometry and spectral type informationfrom the literature in a detailed analysis of the wavelength dependenceof interstellar extinction by dust in these high-latitude clouds. Weinvestigate the shape of the near-infrared extinction curve and evaluatethe total line-of-sight extinction (AV) and ratio oftotal-to-selective extinction (RV) in each line of sight.Sources of uncertainty in RV arising from photometric errorsand spectral classification errors are carefully assessed and quantifiedas functions of the line-of-sight reddening. We detect appreciabledifferences in our results compared with the average extinction curvefor dust in the diffuse interstellar medium (ISM) close to the Galacticplane. Assuming a power-law form in the near-infrared, we find the meanfor high-latitude clouds to be well described by~λ-2.3, somewhat steeperthan that for the diffuse ISM(~λ-1.8). Our sampleincludes a substantial number of lines of sight with low RVvalues (47% with RV<2.8) relative to the diffuse ISMaverage of 3.05+/-0.15. We conclude that many high-latitude clouds haveenhanced abundances of relatively small grains.

Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm

Додај нови чланак


Линкови у сродству са темом

  • - Нема линкова -
Додај нови линк


Чланови следећих група \:


Посматрања и Астрометриски подаци

Сазвежђа:Бик
Ректацензија:03h54m06.96s
Deклинација:+02°11'01.6"
Apparent магнитуда:8.622
Даљина:250.627 parsecs
Proper motion RA:1.3
Proper motion Dec:-4.6
B-T magnitude:8.745
V-T magnitude:8.633

Каталог и designations:
Proper имена
HD 1989HD 24520
TYCHO-2 2000TYC 66-299-1
USNO-A2.0USNO-A2 0900-00884843
HIPHIP 18243

→ Захтевај још каталога од VizieR