J/MNRAS/513/1429 MOBSTER. VI. Radio magnetospheres of hot stars (Shultz+, 2022)
MOBSTER - VI.
The crucial influence of rotation on the radio magnetospheres of hot stars.
Shultz M.E., Owocki S.P., ud-Doula A., Biswas A., Bohlender D., Chandra P.,
Das B., David-Uraz A., Khalack V., Kochukhov O., Landstreet J.D., Leto P.,
Monin D., Neiner C., Rivinius T., Wade G.A.
<Mon. Not. R. Astron. Soc. 513, 1429 (2022)>
=2022MNRAS.513.1429S 2022MNRAS.513.1429S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, early-type ; Magnetic fields
Keywords: magnetic reconnection - stars: early-type - stars: magnetic fields -
stars: rotation - radio continuum: stars
Abstract:
Numerous magnetic hot stars exhibit gyrosynchrotron radio emission.
The source electrons were previously thought to be accelerated to
relativistic velocities in the current sheet formed in the middle
magnetosphere by the wind opening magnetic field lines. However, a
lack of dependence of radio luminosity on the wind power, and a strong
dependence on rotation, has recently challenged this paradigm. We have
collected all radio measurements of magnetic early-type stars
available in the literature. When constraints on the magnetic field
and/or the rotational period are not available, we have determined
these using previously unpublished spectropolarimetric and photometric
data. The result is the largest sample of magnetic stars with radio
observations that has yet been analysed: 131 stars with rotational and
magnetic constraints, of which 50 are radio-bright. We confirm an
obvious dependence of gyrosynchrotron radiation on rotation, and
furthermore find that accounting for rotation neatly separates stars
with and without detected radio emission. There is a close correlation
between Hα emission strength and radio luminosity. These factors
suggest that radio emission may be explained by the same mechanism
responsible for Hα emission from centrifugal magnetospheres,
i.e. centrifugal breakout (CBO), however, while the Hα-emitting
magnetosphere probes the cool plasma before breakout, radio emission
is a consequence of electrons accelerated in centrifugally driven
magnetic reconnection.
Description:
By combining both published and unpublished radio observations,
published rotational and magnetic data, and new determinations of
magnetic models and rotational periods via space photometry and
previously unpublished high- and low-resolution spectropolarimetry, we
have conducted the largest analysis of the gyrosynchrotron emission
properties of magnetic early-type stars undertaken to date.
Tables containing the stellar, rotational, and magnetic parameters and
radio luminosities, as well as tables of longitudinal magnetic field
measurements.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 177 131 Stellar, rotational, magnetic and radio parameters
list.dat 26 40 List of stars with magnetic measurements in
tables A2 and A3
tablea2.dat 63 75 Magnetic measurements with ESPaDOnS and Narval
tablea3.dat 35 252 Magnetic measurements with DAO
refs.dat 69 130 References for Table 1
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Star Name of star
12- 15 F4.2 [Lsun] logL Bolometric luminosity
17- 20 F4.2 [Lsun] e_logL Luminosity error
22- 25 F4.1 kK Teff Effective temperature
28- 30 F3.1 kK e_Teff Effective temperature error
32- 34 I3 --- r_logL Reference for stellar parameters
36- 40 F5.2 Msun Mass Mass
43- 46 F4.2 Msun e_Mass Mass error
48- 50 I3 km/s vsini ? Projected rotational velocity
52- 54 I3 --- r_vsini ? Reference for vsini
56- 64 F9.3 d Prot ? Rotation period
66- 76 A11 --- r_Prot Reference for rotation period
78- 79 I2 deg beta ? Magnetic obliquity angle
81- 82 I2 deg E_beta ? Upper uncertainty in obliquity angle
84- 85 I2 deg e_beta ? Lower uncertainty in obliquity angle
88- 89 A2 --- l_Bd [LL UL] Limit indicator for magnetic field
(LL=lower limit, UL=upper limit)
91- 96 F6.3 kG Bd Surface magnetic dipole strength
98-103 F6.3 kG E_Bd ? Upper uncertainty in surface dipole strength
106-110 F5.3 kG e_Bd ? Lower uncertainty in surface dipole strength
112-134 A23 --- r_Bd Reference for magnetic parameters
137-138 A2 --- l_Lrad [UL] Detection flag for radio data
(UL=upper limit)
140-144 F5.2 Lsun Lrad Radio luminosity
146-149 F4.2 Lsun e_Lrad ? Radio luminosity uncertainty
151-177 A27 --- r_Lrad Reference for radio data
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Star Name of star
12- 13 I2 --- N Number of magnetic measurements
16- 26 A11 --- FileName Name of the table with measurements
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Star Name of star
11 A1 --- Inst Instrument (E=ESPaDOnS,N=Narval)
13- 25 F13.5 d HJD Heliocentric Julian Date
28- 33 F6.1 G Bz Longitudinal magnetic field
37- 41 F5.1 G e_Bz Longitudinal magnetic field error
43- 44 A2 --- DFV Stokes V detection flag (1)
47- 52 F6.1 G Nz Null field
56- 60 F5.1 G e_Nz Null field error
62- 63 A2 --- DFN Null detection flag (1)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
DD = Definite Detection
MD = Marginal Detection
ND = Non-detection
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Star Name of star
11- 23 F13.5 d HJD Heliocentric Julian Date
25- 29 I5 G Bz Longitudinal magnetic field
32- 35 I4 G e_Bz Longitudinal magnetic field error
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Ref Reference key for references in Table 1
5- 23 A19 --- BibCode ADS/CDS bibcode
25- 45 A21 --- Aut Author's name
46- 69 A24 --- Com Comments
--------------------------------------------------------------------------------
Acknowledgements:
Matt Shultz, matt.shultz(at)gmail.com
References:
David-Uraz et al., Paper I 2019MNRAS.487..304D 2019MNRAS.487..304D
Sikora et al., Paper II 2019MNRAS.487.4695S 2019MNRAS.487.4695S
Shultz et al., Paper III 2019MNRAS.490.4154S 2019MNRAS.490.4154S
David-Uraz et al., Paper IV 2021MNRAS.504.4841D 2021MNRAS.504.4841D
Shultz et al., Paper V 2021MNRAS.504.4850S 2021MNRAS.504.4850S
(End) Patricia Vannier [CDS] 18-May-2022