| 11. |
|
|
| 12. |
|
|
| 13. |
- Reipurth, Bo, et al.
(författare)
-
Star formation in BOK globules and low-mass clouds. V - H-alpha emission stars near SA 101, CG13 and CG22
- 1993
-
Ingår i: Astronomy and Astrophysics. - : Springer. - 0004-6361 .- 1432-0746. ; 267:2, s. 439-446
-
Tidskriftsartikel (refereegranskat)abstract
- We have surveyed five fields in the Gum Nebula containing cometary globules, in a search for new regions of low-mass star formation. Seven H-alpha emission stars were found in association with the CG4/CG6/Sa101 cloud complex, and one in association with the CG13 globule. All eight stars are late-type emission line stars, and appear to be low-mass pre-main sequence stars. Low dispersion spectra and optical and IR photometry are presented for the objects, as well as for PH-alpha 92, an already known young star in CG22. Most of the globules surveyed are not associated with H-alpha emission stars. We demonstrate that star formation has occurred in the Gum Nebula over several million years, right up to very recently.
|
|
| 14. |
- Hernius, O, et al.
(författare)
-
Astrometry of outer Jovian satellites from the Uppsala-ESO survey of asteroids and comets (UESAC)
- 1996
-
Ingår i: ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES. - : EDITIONS PHYSIQUE. - 0365-0138. ; 115:2, s. 295-296
-
Tidskriftsartikel (refereegranskat)abstract
- In the course of The Uppsala-ESO Survey of Asteroids and Comets astrometric positions of the faint outer Jovian satellites J VI-XIII were obtained from photographic plates and films taken at the European Southern Observatory, La Silla, Chile and at the An
|
|
| 15. |
- EDVARDSSON, Bengt, et al.
(författare)
-
ABUNDANCE ANALYSIS AND ORIGIN OF THE ZETA-SCULPTORIS OPEN CLUSTER
- 1995
-
Ingår i: ASTRONOMY AND ASTROPHYSICS. - : SPRINGER VERLAG. - 0004-6361. ; 293:1, s. 75-86
-
Tidskriftsartikel (refereegranskat)abstract
- We have determined chemical abundances and radial velocities for stars in the field of the zeta Sculptoris cluster. We find that the cluster metal deficiency previously found from UBV photometry is not supported; the cluster overall metallicity, [Fe/H] =
|
|
| 16. |
- Magnusson, P, et al.
(författare)
-
Photometric observations and modeling of asteroid 1620 Geographos
- 1996
-
Ingår i: ICARUS. - : ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS. - 0019-1035. ; 123:1, s. 227-244
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Photometric observations of 1620 Geographos in 1993 and 1993 are presented and, in combination with previously published data, are used to derive models of Geographos, We estimate that the sidereal period of rotation is 0.21763860 +/- 0.00000003 days (5(h
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
- Asplund, Martin, et al.
(författare)
-
Abundance similarities between the R CrB star V854 Cen and the born-again Sakurai's object
- 1998
-
Ingår i: ASTRONOMY AND ASTROPHYSICS. - : SPRINGER VERLAG. - 0004-6361. ; 332:2, s. 651-660
-
Tidskriftsartikel (refereegranskat)abstract
- The elemental abundances of the mildly hydrogen-deficient R Coronae Borealis (R CrB) star V854 Cen have been estimated. The R CrB stars have been divided into majority and minority classes judging by their abundance patterns. Class assignment has previous
|
|
| 20. |
- Alberdi, A., et al.
(författare)
-
The high-frequency compact radio structure of the peculiar quasar 4C 39.25
- 1997
-
Ingår i: Astronomy and Astrophysics. - : Springer-Verlag. - 0004-6361 .- 1432-0746. ; 327:2, s. 513-521
-
Tidskriftsartikel (refereegranskat)abstract
- We present new high angular resolution images of the compact non-thermal radio source 4C 39.25 obtained from VLBI observations at λ1.3cm, λ7mm, and λ3mm wavelengths. These maps and Gaussian model-fits show that the milli-arcsecond to sub-milliarcsecond structure of 4C 39.25 consists of a complex bent core-jet structure with embedded moving and stationary VLBI components. Facilitated by the small observing beams and high angular resolutions obtained at mm-wavelengths, we measured the relative positions of the jet components with an accuracy of a few hundred micro-arcseconds. This allows the detailed followup of the ongoing merging process of a westward superluminally moving component (b_) with a stationary component a_, located at ~2.9 mas east of the putative core d_. In contrast to the other components of the structure with steeper spectra, the westernmost component d_ exhibits an inverted spectrum peaking between λ7mm and λ3mm, thus further supporting its identification as the VLBI core, self-absorbed at longer wavelengths. From two VLBI maps obtained nearly simultaneously at λ7mm and λ1.3cm, we made the first spectral index map of 4C 39.25 in this wavelength regime. The main characteristics of the spectral index distribution of the jet are pronounced changes of the spectral index between orientations parallel and transverse to the jet axis. Near the merging components a_ and b_ the spectral index steepens with increasing separation from d_. However, in the bridge of emission c_, which connects d_ with a_ and b_, the spectral index gradient has a direction transverse to the jet axis, suggesting a frequency dependent jet curvature and edge-brightening. A brief discussion of this behaviour within current jet models is presented.
|
|
