תוכן
תמונות
הוסף תמונה שלך
DSS Images Other Images
מאמרים קשורים
A search for previously unrecognized metal-poor subdwarfs in the Hipparcos astrometric catalogue
We have identified 317 stars included in the Hipparcos astrometriccatalogue that have parallaxes measured to a precision of better than 15per cent, and the location of which in the(MV,(B-V)T) diagram implies a metallicitycomparable to or less than that of the intermediate-abundance globularcluster M5. We have undertaken an extensive literature search to locateStrömgren, Johnson/Cousins and Walraven photometry for over 120stars. In addition, we present new UBV(RI)C photometry of 201of these candidate halo stars, together with similar data for a further14 known metal-poor subdwarfs. These observations provide the firstextensive data set of RCIC photometry ofmetal-poor, main-sequence stars with well-determined trigonometricparallaxes. Finally, we have obtained intermediate-resolution opticalspectroscopy of 175 stars. 47 stars still lack sufficient supplementaryobservations for population classification; however, we are able toestimate abundances for 270 stars, or over 80 per cent of the sample.The overwhelming majority have near-solar abundance, with theirinclusion in the present sample stemming from errors in the colourslisted in the Hipparcos catalogue. Only 44 stars show consistentevidence of abundances below [Fe/H]=-1.0. Nine are additions to thesmall sample of metal-poor subdwarfs with accurate photometry. Weconsider briefly the implication of these results for clustermain-sequence fitting.
|
הכנס מאמר חדש
לינקים קשורים
הכנס לינק חדש
משמש של הקבוצה הבאה
|
תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | ארנבת |
| התרוממות ימנית: | 05h14m22.31s |
| סירוב: | -24°27'51.1" |
| גודל גלוי: | 9.361 |
| תנועה נכונה: | 48.6 |
| תנועה נכונה: | -36.6 |
| B-T magnitude: | 9.946 |
| V-T magnitude: | 9.41 |
קטלוגים וכינוים:
|
