2004A&A...423.1095L


Query : 2004A&A...423.1095L

2004A&A...423.1095L - Astronomy and Astrophysics, volume 423, 1095-1099 (2004/9-1)

Extending the radio spectrum of magnetic chemically peculiar stars to the mm range.

LEONE F., TRIGILIO C., NERI R. and UMANA G.

Abstract (from CDS):

Magnetic chemically peculiar (MCP) stars can present radio emission at centimetre wavelengths. The steep decrement of the dominant dipolar component of the photospheric magnetic field results in each radio frequency being mainly emitted in a well localised shell of the circumstellar region. To explore the most internal regions of the magnetosphere, observations of a sample of eleven MCP stars known to be radio sources in the 1.4-22.5GHz range were carried out at 87.7 GHz with the IRAM interferometer. Millimeter emission, with a flux density at about 4xthe sensitivity limit of our observations, was detected towards two of the stars: HD 35298 and HD 124224. Combining our mm-observations with previous cm-observations, it appears that MCP stars with a relatively weak magnetic field present a radio spectrum that increases with frequency up to 22.5GHz and then decreases towards the mm range. In presence of strong fields, the radio spectrum is always decreasing with frequency. A comparison of the observed cm-mm spectrum of HD 124224 with results of numerical simulations of the gyrosynchrotron emission suggests that circumstellar regions emitting in the mm-range cannot present magnetic fields larger than 1-2kG.

Abstract Copyright:

Journal keyword(s): stars: chemically peculiar - stars: individual: HD 35298, HD 124224 - stars: circumstellar matter - stars: magnetic field - radio continuum: 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 - 2022
#notes
1 V* V1156 Ori Ro* 05 23 50.3591328504 +02 04 55.824899052   7.78 7.91     B7IV 122 0
2 * del02 Ori SB* 05 32 00.4064140728 -00 17 04.347484800 5.97 6.67 6.83     B2Vsn 272 0
3 V* V1046 Ori SB* 05 35 21.8667428568 -04 29 39.024375324 5.66 6.43 6.56 6.61 6.74 B2/3V 290 0
4 * sig Ori E Y*O 05 38 47.2050040320 -02 35 40.521424812 5.66 6.38 6.46 6.84 7.08 B2IV-Vp_He 430 0
5 V* V1051 Ori a2* 05 40 46.1919736920 -10 24 31.195469484 5.88 6.36 6.52     B9III 82 0
6 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5600 1
7 V* CU Vir a2* 14 12 15.8054758 +02 24 33.953395 4.46 4.90 5.02 5.10 5.23 ApSi 374 0
8 * 3 Sco Ro* 15 54 39.5296532472 -25 14 37.459966128 5.23 5.81 5.87     B8III/IV 203 0
9 V* V913 Sco Ro* 15 58 34.8665694960 -24 49 53.361727284 4.70 5.34 5.43     B5V 195 0
10 HD 144334 ** 16 06 06.3891324384 -23 36 22.849641396 5.29 5.84 5.92     B8V 185 0
11 V* V2393 Oph a2* 18 33 23.3029636152 +08 16 05.698559100 6.05 6.379 6.416     B9III 68 0
12 EM* MWC 349 ** 20 32 45.499080 +40 39 36.74124   15.88 13.15 12.13   Bep 759 0
13 V* GL Lac a2* 22 44 07.5047456400 +55 35 21.211012248   8.85 8.81     A0p 274 0

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2022.10.01-14:18:18

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