2004A&A...428..535M


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.12CET23:45:13

2004A&A...428..535M - Astronomy and Astrophysics, volume 428, 535-543 (2004/12-3)

An optical absorption study of the Helix planetary nebula NaI and CaII lines, and a search for diffuse bands.

MAURON N. and KENDALL T.R.

Abstract (from CDS):

We present the first results of an optical absorption study of NGC 7293, the Helix planetary nebula (PN), designed to search definitively for diffuse band (DIB) absorptions perhaps arising in the carbon-rich circumstellar matter of the PN. We used the VLT-UVES spectrograph to achieve high resolution (R=50000) spectra of 8 stars located angularly close to and behind the Helix. These targets were selected through their photometric UBV or 2MASS properties, permitting derivation of spectral types (mainly F-G dwarfs) and distance that place several of them far (700-1500pc) beyond the Helix (210pc). Through a detailed analysis of the Nai and Caii lines to the 8 targets, we find that two lines of sight situated close to the nebula as mapped in CO and Hi exhibit very strong Nai absorption. This absorption is unlikely to arise in the foreground or background interstellar medium which has a relatively low column density, because the Helix is at high galactic latitude b=-57°. It is much more probable that it is due to the PN neutral or molecular material. This circumstellar origin is reinforced by the fact that no corresponding Caii line is observed (as it would usually be from the ISM), which is in agreement with the very high Ca depletion often observed in PNs. No trace of any DIB features was found in these two circumstellar lines of sight, nor to the other targets. The two circumstellar sightlines discovered in this work open the way to search for molecular species such as C2 which are not observable at radio wavelengths, and to obtain more information on the rich neutral and molecular content of the Helix.

Abstract Copyright:

Journal keyword(s): planetary nebulae: individual: NGC 7293 - planetary nebulae: general - circumstellar matter - ISM: lines and bands - ISM: molecules

Simbad objects: 20

goto Full paper

goto View the reference in ADS

Number of rows : 20

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 44179 pA* 06 19 58.2185496 -10 38 14.706068 9.51 9.33 9.02     B9Ib/II 704 0
2 BM IV 10 C* 07 29 12.5853048852 -19 27 48.652896159   13.44 12.13 10.41 9.44 C 49 0
3 IRC +10216 C* 09 47 57.406 +13 16 43.56     10.96     C9,5e 2105 0
4 HD 89353 pA* 10 18 07.5892879413 -28 59 31.194541133   5.76 5.53     B9.5Ib/II 284 0
5 V* V854 Cen RC* 14 34 49.4088471574 -39 33 19.276531885   7.13       Ce 195 0
6 NGC 7027 PN 21 07 01.8 +42 14 10   9.1 10.9     ~ 2302 1
7 * 35 Aqr * 22 08 58.9903290966 -18 31 10.537244071   5.629 5.793     B2III 81 0
8 HD 213056 * 22 29 09.4363451901 -20 46 07.402517352   10.958 9.912     K1(III) 6 0
9 HD 213069 PM* 22 29 13.1322567392 -20 57 48.823930642   11.035 10.436     F5/6(V) 5 0
10 NGC 7293 PN 22 29 38.5453078023 -20 50 13.746093105 11.894 13.158 13.524 13.689 13.898 DAO.5 883 0
11 USNO-B1.0 0692-00882044 * 22 31 52.74 -20 30 40.6   10.6 9.9     ~ 1 0
12 USNO-B1.0 0690-00897288 * 22 31 56.54 -20 42 21.9   10.8 10.4     ~ 1 0
13 USNO-B1.0 0691-00897309 * 22 32 02.24 -20 33 20.7   14.9       ~ 1 0
14 USNO-B1.0 0692-00882100 * 22 32 16.77 -20 30 50.9   13.3       ~ 1 0
15 USNO-B1.0 0691-00897340 * 22 32 21.96 -20 34 46.6   13.1 13.7     ~ 1 0
16 USNO-B1.0 0690-00897407 * 22 32 29.77 -20 41 05.6   14.1       ~ 1 0
17 USNO-B1.0 0691-00897349 * 22 32 30.55 -20 35 02.1   13.9 14.0     ~ 1 0
18 USNO-B1.0 0691-00897499 * 22 33 11.16 -20 33 02.1   12.0 11.7     ~ 1 0
19 HD 214080 V* 22 36 06.4359613479 -16 23 16.759751314 6.00 6.81 6.93 6.99 7.06 B1/2Ib 128 0
20 V* HN Aqr bC* 22 37 38.2846197264 -18 39 51.268673991   11.28 11.47     B 58 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2004A&A...428..535M and select 'bookmark this link' or equivalent in the popup menu


2019.11.12-23:45:13

© Université de Strasbourg/CNRS

    • Contact