1999A&A...346..969W


Query : 1999A&A...346..969W

1999A&A...346..969W - Astronomy and Astrophysics, volume 346, 969-978 (1999/6-3)

Evidence for an ionization gradient in the local interstellar medium: EUVE observations of white dwarfs.

WOLFF B., KOESTER D. and LALLEMENT R.

Abstract (from CDS):

We present an enlarged and homogeneous set of interstellar hydrogen and helium column densities obtained through continuum and ionization edges fitting of nearby hot white dwarfs observed with the Extreme Ultraviolet Explorer (EUVE). We compare the HI columns towards the targets and their locations relative to the soft X-ray cavity contours drawn by Snowden et al. (1998ApJ...493..715S). We then use the inferred ionization degrees of hydrogen and helium (available towards 17 objects) as a database for a search of systematic trends in the local interstellar medium. We find that the ionization degree of helium does not show any trend, with a constant value around 40%. At variance with helium, hydrogen ionization varies within the Local Bubble: there is an ionization increase along the general direction of the Canis Major cavity. These results are consistent with hydrogen being ionized by the Canis Major hot stars Adara and Mirzam. However, the co-existence of fully neutral hydrogen and strongly ionized helium along some l-o-s remains to be explained.

Abstract Copyright:

Journal keyword(s): stars: white dwarfs - ISM: abundances - ISM: structure - ultraviolet: ISM

Simbad objects: 32

goto View the references in ADS

Number of rows : 32
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 GD 2 WD* 00 07 32.2596836786 +33 17 27.606663558 12.321 13.482 13.791 13.940 14.119 DA1.0 91 0
2 GD 659 WD* 00 53 17.4281797444 -32 59 56.524788340   13.14 13.36     DA1.4 127 0
3 HD 15638 SB* 02 28 19.0274746553 -61 18 19.326235612   9.28 8.88     F6V+D 50 0
4 RX J0512.0-0042 WD* 05 12 06.3899707360 -00 42 05.958677070   13.5 13.8 13.9   DA1.6 41 0
5 * 14 Aur C XB* 05 15 23.5994864232 +32 41 05.235770037   8.25 7.88     F2V+DA1.3 75 2
6 GD 71 WD* 05 52 27.6197286025 +15 53 13.228639956 11.675 12.783 13.032 13.169 13.337 DA1.5 346 0
7 * bet CMa bC* 06 22 41.9853527 -17 57 21.307352 0.77 1.73 1.97 2.11 2.35 B1II-III 692 0
8 RX J0632.9-0506 WD* 06 32 57.7843002479 -05 05 49.361267765   15.7 15.537 16.0   DA1.1 28 0
9 * alf CMa B WD* 06 45 09.3021501316 -16 43 00.716804119   8.41 8.44     DA1.9 504 1
10 * eps CMa * 06 58 37.54876 -28 58 19.5102 0.36 1.29 1.50 1.59 1.80 B1.5II 467 1
11 RX J0715.3-7025 WD* 07 15 16.5784417981 -70 25 05.619208952   13.97 14.178 14.12   DA1 50 0
12 RX J0723.2-2748 WD* 07 23 20.0981540647 -27 47 21.575306556   13.9   14.2   DA1.4 30 0
13 RX J1032.1+5329 WD* 10 32 09.9866417395 +53 29 35.371126847   13.5 14.455     DA1.1 82 0
14 PG 1057+719 WD* 11 00 34.2433198635 +71 38 02.919515746   14.95 14.68 15.23   DA1.2 67 0
15 PG 1123+189 CV* 11 26 19.095480 +18 39 16.56900   13.94 14.10 14.31   DA.9 64 0
16 PG 1234+482 WD* 12 36 45.1438119188 +47 55 22.219209993     14.38     DA.9 90 2
17 GD 153 WD* 12 57 02.3224875106 +22 01 52.634392478 11.883 13.060 13.349 13.488 13.669 DA1.2 326 0
18 HZ 43A WD* 13 16 21.8529879473 +29 05 55.413524767   12.52 12.66     DAwk 457 0
19 RX J1546.9-3646 WD* 15 46 58.2731091924 -36 46 42.576010613   15.7 15.81     DA1.1 29 0
20 CD-38 10980 WD* 16 23 33.8384178546 -39 13 46.160032569 9.916 10.885 11.029 10.936 10.841 DA2 449 0
21 RX J1629.0+7804 WD* 16 29 10.278576 +78 04 39.91620   12.74 12.95 13.03   DA1.2 85 0
22 PG 1658+441 WD* 16 59 48.4241733860 +44 01 04.041324412   14.3 14.6     DAP1.6 133 0
23 1RXS J174614.9-703902 WD* 17 46 13.8238151839 -70 38 57.824492355   16.6 16.0 16.1   DA1.0 33 0
24 Lan 18 WD* 18 47 39.0285643340 +01 57 35.440019889 11.68 12.73 12.94 13.1 12.3 DA1.7 73 0
25 RX J2009.1-6025 WD* 20 09 05.6035755667 -60 25 42.532886256 11.94 13.11 13.39 13.69   DA1.2 59 0
26 V* IK Peg dS* 21 26 26.6606623779 +19 22 32.316865675   6.294 6.064     kA6hA9mF0+DA 174 0
27 RX J2156.4-5438 WD* 21 56 21.2577774215 -54 38 23.015921071 13.11 14.29 14.58     DA1 53 0
28 Lan 23 WD* 22 49 52.3671986585 +58 34 32.041440841 12.80 13.98 14.19 14.78   DA.9 39 0
29 GD 246 WD* 23 12 21.6156138550 +10 47 04.257261526 11.578 12.772 13.090 13.238 13.418 DA.9 206 0
30 RX J2324.5-5441 WD* 23 24 30.8621078302 -54 41 35.509209471   14.91 15.13 15.72   DA1.1 51 0
31 NAME CMa Region reg ~ ~           ~ 41 0
32 NAME Local Bubble ISM ~ ~           ~ 741 0

To bookmark this query, right click on this link: simbad:objects in 1999A&A...346..969W and select 'bookmark this link' or equivalent in the popup menu


2021.08.04-13:30:39

© Université de Strasbourg/CNRS

    • Contact