2021A&A...651A..35O


Query : 2021A&A...651A..35O

2021A&A...651A..35O - Astronomy and Astrophysics, volume 651A, 35-35 (2021/7-1)

Heavy-element Rydberg transition line emission from the post-giant-evolution star HD 101584.

OLOFSSON H., BLACK J.H., KHOURI T., VLEMMINGS W.H.T., HUMPHREYS E.M.L., LINDQVIST M., MAERCKER M., NYMAN L., RAMSTEDT S. and TAFOYA D.

Abstract (from CDS):


Context. We report the detection of two lines at millimetre wavelengths towards the immediate surroundings of the post-giant and most likely post-common-envelope star HD 101584 using high-angular-resolution ALMA observations. The circumstellar environment of this object is rich in different molecular species, but we find no viable identifications in terms of molecular lines.
Aims. We aim to determine whether or not these lines can be attributed to the Rydberg transitions - X30α and X26α - of neutral atoms of elements heavier than carbon.
Methods. A simple model in strict local thermodynamic equilibrium for a warm-gas environment of the moderate-temperature star (Teff≃8500K) was constructed to corroborate our findings. A geometrically thin, disc-like geometry seen face-on was chosen and a distance of 1kpc.
Results. The observed flux densities of the lines and the continuum at 232 and 354GHz can be reproduced using ≃10–3M of gas at a temperature of ≃2800K and a hydrogen density of ≃1012cm–3, assuming solar abundances for the elements. The gas lies within a distance of about 5 au from the star (assuming a distance of 1kpc). The ionisation fraction is low, ≃3x10–5. The origin of such a region is not clear, but it may be related to a common-envelope-evolution phase. With these conditions, the line emissions are dominated by Rydberg transitions within the stable isotopes of Mg. A turbulent velocity field in the range 5.5-7.5km/s is required to fit the Gaussian line shapes. An upper limit to the average magnetic field in the line-emitting region of 1G is set using the Zeeman effect in these lines.
Conclusions. We speculate that Rydberg transitions of heavy elements may be an interesting probe for the close-in environments of other moderate-temperature objects like AGB stars, red supergiants, yellow hypergiants, and binaries of various types.

Abstract Copyright: © ESO 2021

Journal keyword(s): circumstellar matter - stars: individual: HD 101584 - stars: AGB and post-AGB - radio lines: stars

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 * alf Ori s*r 05 55 10.30536 +07 24 25.4304 4.38 2.27 0.42 -1.17 -2.45 M1-M2Ia-Iab 1593 0
2 QSO J0635-7516 QSO 06 35 46.5079301472 -75 16 16.816418256   15.96 15.75 15.82   ~ 558 1
3 QSO B1034-293 QSO 10 37 16.07974265 -29 34 02.8134977   16.46 16.46 17.54   ~ 309 1
4 * eta Car Em* 10 45 03.5377808928 -59 41 04.051599720 6.37 7.03 6.48 4.90 4.41 OBepec 2363 0
5 QSO B1104-445 QSO 11 07 08.69412105 -44 49 07.6183013   17.84 18.2 17.37   ~ 222 1
6 ICRF J113143.2-581853 QSO 11 31 43.2884970000 -58 18 53.444745216   19.06       ~ 22 0
7 PMN J1132-5606 Rad 11 32 16.41482 -56 06 44.7308           ~ 13 1
8 HD 101584 pA* 11 40 58.8051522552 -55 34 25.814696232 7.80 7.40 7.01     B8/9I/IIe 133 0
9 PMN J1150-5416 Rad 11 50 33.93 -54 16 42.5           ~ 3 0
10 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3446 1
11 WRAY 15-1676 pA* 17 19 49.3290860880 -39 10 37.928806356     13.1     ~ 44 1
12 V* RR Tel Sy* 20 04 18.5404499712 -55 43 33.153979080 9.93 11.33 10.81 11.689   M5e 528 0
13 V* VV Cep EB* 21 56 39.1438495 +63 37 32.017439 7.03 6.65 4.90 3.19 1.85 M2epIa-Iab+B8:eV 442 1

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2023.01.27-23:09:32

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