1997A&A...322..291E


Query : 1997A&A...322..291E

1997A&A...322..291E - Astronomy and Astrophysics, volume 322, 291-295 (1997/6-1)

Mode switching of the water maser in OH 39.7+1.5.

ENGELS D., WINNBERG A., WALMSLEY C.M. and BRAND J.

Abstract (from CDS):

Monitoring of the H2O maser in OH 39.7+1.5 as well as spatial interferometry show clear evidence that the maser switches occasionally its beaming direction between radial and tangential paths in step with the stellar pulsation cycle. Outside the minimum, several radially beamed maser features are present, which are absent (≤20mJy) during the minimum. Competition between gain paths causes tangentially beamed maser emission only to occur, when the temperature in the maser shell is too low to excite radially beamed masers. The radius of the H2O maser shell extends between 6x1014cm (40AU) and at least 3x1015cm (200AU), with the inner radius probably set by quenching of the maser due to high gas density close to the star. Within the H2O maser shell, the circumstellar outflow accelerates from v≃9km/s up to the terminal expansion velocity of ≃18km/s. The expansion velocity of the circumstellar shell is constant between the outer radius of the water maser shell and the location of the 1612MHz OH maser shell at 3x1016cm, showing the absence of strong velocity gradients at large radial distances.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - masers - stars: individual: OH 39.7+1.5 - radio lines: stars

Simbad objects: 4

goto View the references in ADS

Number of rows : 4
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 3C 84 Sy2 03 19 48.1599902040 +41 30 42.108850836   13.10 12.48 11.09   ~ 3766 3
2 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4059 2
3 RAFGL 2290 OH* 18 58 30.0951077544 +06 42 57.696212124           O-rich 123 0
4 ICRF J192559.6+210626 BLL 19 25 59.60535560 +21 06 26.1620442           ~ 187 1

To bookmark this query, right click on this link: simbad:objects in 1997A&A...322..291E and select 'bookmark this link' or equivalent in the popup menu


2022.05.22-23:20:29

© Université de Strasbourg/CNRS

    • Contact