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J/ApJ/439/983     Radio & optical observation of UX Arietis (Elias+ 1995)

Correlations between the flaring radio emission and starspot distribution of UX Arietis Elias N.M. II, Quirrenbach A., Witzel A., Naundorf C.E., Wegner R., Guinan E.F., McCook G.P. <Astrophys. J. 439, 983 (1995)> =1995ApJ...439..983E
ADC_Keywords: Stars, flare ; Photometry ; Radio lines Keywords: radio continuum: stars - stars: flare - stars: individual (UX Arietis) Abstract: We have observed UX Arietis at C band (6cm) for 3 weeks with four VLA antennas. The temporal coverage during the program was approximately three scans per day. A few days into the VLA program, UX Ari began a radio flaring period which lasted for at least 2 weeks. All the radio fluxes were above the system noise during this episode, but the largest values (up to 270mJy) occurred close to 0.0 phase. This phasing is confirmed by the UX Ari radio observations of Neidhoefer, Massi, & Chiuderi-Drago (1993A&A...278L..51N). Visible-band light curves of UX Ari were obtained both during and after our radio observations; the peak-to-peak variation in all filters was ∼0.2mag. The light curves indicate that the maximum starspot visibility occurred very close to 0.0 phase, the same phase as the radio maxima. Closer comparison of our radio and optical light curves indicates that they are almost perfectly anticorrelated. A similar radio/optical correlation has been found by Lim et al. (1992ApJ...388L..27L) and Lim et al. (1994ApJ...430..332L) for the single K0 V star AB Dor. We make the following conclusions from our observations. First, the episodes of long-term (∼hours to days) radio flaring were modulated by stellar eclipses. Second, the flares were located close to the starspot groups. Third, the sizes of the flares were comparable to sizes of the starspot groups, which is consistent with nonthermal emission of brightness temperature T_b∼1010-1013K. Fourth, the radio emission arose only from the midlatitude starspot groups. Last, the radio flares emitted their radiation nearly normal to the stellar surface. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 03 26 35.1 +28 42 59 UX Ari = HD 21242 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file radio 23 42 UX Arietis C-band VLA observations optical 34 418 UX Arietis visible-band photometry
Byte-by-byte Description of file: radio
Bytes Format Units Label Explanations
1- 12 F12.4 d HJD Heliocentric Julian Date 14- 19 F6.4 --- Phase [0/1[ Phase 21- 23 I3 mJy Flux Radio flux
Byte-by-byte Description of file: optical
Bytes Format Units Label Explanations
1- 13 F13.5 d HJD Heliocentric Julian Date 15- 21 F7.5 --- Phase [0/1[ Phase 23- 27 F5.3 mag dMag *Differential magnitude, Var - Comp 29- 30 A2 --- Filter *Filter: b', y, r 32- 34 A3 --- Obs *Observatory, VUO or APT
Note on dMag: Comparison star was 62 Ari (HR 1012, HD 20825; V=+5.52; B-V=+1.10; G5 III). Check star was HR 999 (HD 20644, V=+4.47, B-V=+1.54; K4 III). 62 Ari has been used previously in photometric studies of UX Ari and appears to be constant in light. Note on Filter: Intermediate-band interference filters: b' - lambda = 453nm, FWHM = 15nm y - Stroemgren y, lambda = 550nm, FWHM = 35nm r - lambda = 660nm, FWHM = 28nm, also known as H-alpha I Note on Obs: VUO - Villanova University Observatory, APT - Automatic Photometric Telescope, Mount Hopkins, Arizona
Origin: AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 06-May-1995
(End) [CDS] 11-Jul-1995
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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