Home     To Survive in the Universe    
Services
    Why to Inhabit     Top Contributors     Astro Photo     The Collection     Forum     Blog New!     FAQ     Login  
→ Adopt this star  

HD 143669


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

Behaviour of the HeI 587.6, 667.8, 706.5 and 728.1nm lines in B-type stars. On the helium stratification in the atmosphere of magnetic helium peculiar stars.
High resolution spectra of the HeI587.6, 667.8 706.5 and 728.1nm lineshave been obtained to test the prediction (notably by Vauclair et al.1991) that helium abundance should decrease with depth in helium richstars and increase in helium weak stars. A sample of B-type mainsequence stars, with expected solar abundances and non stratifiedatmospheres, have also been observed in order to compare the behaviourof the selected lines with the chemically peculiar case and with theory.We found significant discrepancies with theory for the lines HeI 706.5.and 728.1nm, and, in order to outline differences between 'normal' and'peculiar' stars, we have adopted an empirical correction to the Lorentzbroadening parameter in the Voigt profile, under the assumption of LTE.This parameter is derived from the imposition of a satisfactory fit withobservations for the relation equivalent width vs. effective temperaturefor normal B stars. For helium rich stars we confirm Vauclair et al.(1991) predictions that helium abundance decreases with depth. However,we found that helium abundance decreases with depth in helium weak starstoo, which contradicts Vauclair et al. (1991) predictions. For somepeculiar stars, the inferred helium abundance is in disagreement withthe peculiarity class reported in the General Catalogue of Ap and Amstars (Renson et al. 1991).

Photoelectric radial velocities, Paper XIII - 406 ninth-magnitude K0 stars in the Clube Selected Areas
Radial velocities are given for 406 ninth-magnitude late-type stars. Thestars are grouped in 10 small regions located on a systematic plan atGalactic latitudes of + or - 35 deg. Each star has been observed atleast twice, and the mean velocities are accurate to about less than 1km/s. Thirty spectroscopic binaries have been discovered; orbits havealready been given for 13 of them, and observations of the others arecontinuing.

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:Ophiuchus
Right ascension:16h02m01.14s
Declination:-06°27'42.6"
Apparent magnitude:8.722
Distance:322.581 parsecs
Proper motion RA:1.9
Proper motion Dec:41
B-T magnitude:10.087
V-T magnitude:8.835

Catalogs and designations:
Proper Names
HD 1989HD 143669
TYCHO-2 2000TYC 5044-176-1
USNO-A2.0USNO-A2 0825-09059228
HIPHIP 78535

→ Request more catalogs and designations from VizieR