Főoldal     Alapinformációk     To Survive in the Universe    
Inhabited Sky
    News@Sky     Asztrofotók     Kollekció     Fórum     Blog New!     GYIK     Sajtó     Bejelentkezés  

HD 196469


Tartalom

Képek

Kép feltöltése

DSS Images   Other Images


Kapcsolódó cikkek

The local distribution of NA I interstellar gas
We present high-resolution absorption measurements (lambda/Delta lambdaapproximately 75,000) of the interstellar Na I D lines at 5890 A toward80 southern hemisphere early-type stars located in the localinterstellar medium (LISM). Combining these results with other sodiummeasurements taken from the literature, we produce galactic maps of thedistribution of neutral sodium column density for a total of 293 starsgenerally lying within approximately 250 pc of the Sun. These mapsreveal the approximate shape of the mid-plane contours of the rarefiedregion of interstellar space termed the Local Bubble. Its shape is seenas highly asymmetric, with a radius ranging from 30 to 300 pc, and withan average radius of 60 pc. Similar plots of the Galactic mid-planedistribution of sources emitting extreme ultraviolet radiation show thatthey also trace out similar contours of the Local Bubble derived from NaI absorption measurements. We conclude that the Local Bubble absorptioninterface can be represented by a hydrogen column density,NuETA = 2 x 1019 cm-2, which explainsboth the local distribution of Na I absorption and the observed galacticdistribution of extreme ultraviolet sources. The derived mid-planecontours of the Bubble generally reproduce the large-scale featurescarved out in the interstellar medium by several nearby galactic shellstructures.

Estimation of the equivalent width of the interstellar CA II K absorption line
Literature values for the equivalent width of the interstellarabsorption line of Ca II K (3933 A) are used to constrain a simpleempirical model for the strength of this line as a function of distancefrom the galactic plane. The best-fit model has an integrated Ca II Kequivalent width in the direction perpendicular to the galactic plane ofapproximately 200 mA and a 'scale height' of approximately 1100 pc. Sucha model is useful for estimating (and correcting for) the contributionof the interstellar Ca II K feature to the total observed Ca II K linestrength in the spectra of metal-deficient stars in the galactic halo.

Interstellar absorption lines in the directions of extragalactic objects. II - Analysis of 25 sight lines
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986MNRAS.220..927M&db_key=AST

Új cikk hozzáadása


Kapcsolódó hivatkozások

  • - (nincs kapcsolódó hivatkozás) -
Új link hozzáadása


Besorolás csoportokba:


Pozíciós és asztrometriai adatok

Csillagkép:Bak
Rektaszcenzió:20h37m55.86s
Deklináció:-11°01'59.2"
Vizuális fényesség:7.177
Távolság:332.226 parszek
RA sajátmozgás:2.4
Dec sajátmozgás:-28.9
B-T magnitude:7.14
V-T magnitude:7.174

Katalógusok és elnevezések:
Megfelelő nevek   (Edit)
HD 1989HD 196469
TYCHO-2 2000TYC 5759-2274-1
USNO-A2.0USNO-A2 0750-20258163
HIPHIP 101811

→ További katalógusok és elnevezések lekérése VizieR-ből