scholarly journals Detection of new pulsations in the roAp star HD 177765

2016 ◽  
pp. 1-5
Author(s):  
Holdsworth Daniel L.
Keyword(s):  
Roap Star

scholarly journals KIC 7582608: a new Kepler roAp star with frequency variability

2014 ◽  
Vol 443 (3) ◽  
pp. 2049-2062 ◽  
Author(s):  
Daniel L. Holdsworth ◽  
B. Smalley ◽  
D. W. Kurtz ◽  
J. Southworth ◽  
M. S. Cunha ◽  
...  
Keyword(s):  
Roap Star

scholarly journals Spectroscopy of the roAp star   Cir - II. The bisector and equivalent width of the H  line

1999 ◽  
Vol 302 (2) ◽  
pp. 381-390 ◽  
Author(s):  
I. K. Baldry ◽  
M. Viskum ◽  
T. R. Bedding ◽  
H. Kjeldsen ◽  
S. Frandsen
Keyword(s):  
Equivalent Width ◽  
Roap Star

scholarly journals First Magnetic Doppler Images of a roAp star

2007 ◽  
Vol 150 ◽  
pp. 85-86 ◽  
Author(s):  
T. Lüftinger
Keyword(s):  
Roap Star

scholarly journals The fundamental parameters of the roAp star 10 Aquilae

2013 ◽  
Vol 559 ◽  
pp. A21 ◽  
Author(s):  
K. Perraut ◽  
S. Borgniet ◽  
M. Cunha ◽  
L. Bigot ◽  
I. Brandão ◽  
...  
Keyword(s):  
Fundamental Parameters ◽  
Roap Star

scholarly journals HD 12098 -A new northern hemisphere roAp star

2001 ◽  
Vol 380 (1) ◽  
pp. 142-147 ◽  
Author(s):  
V. Girish ◽  
S. Seetha ◽  
P. Martinez ◽  
S. Joshi ◽  
B. N. Ashoka ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Roap Star

scholarly journals HD 42659: the only known roAp star in a spectroscopic binary observed with B photometry, TESS, and SALT

2019 ◽  
Vol 489 (3) ◽  
pp. 4063-4071 ◽  
Author(s):  
Daniel L Holdsworth ◽  
Hideyuki Saio ◽  
Donald W Kurtz
Keyword(s):  
Signal To Noise Ratio ◽  
Rotation Frequency ◽  
Close Binaries ◽  
High Signal ◽  
Pulsation Frequency ◽  
Orbital Parameters ◽  
Mode Amplitude ◽  
Photometric Observations ◽  
Short Period ◽  
Roap Star

ABSTRACT We present a multi-instrument analysis of the rapidly oscillating Ap (roAp) star HD 42659. We have obtained B photometric data for this star and use these data, in conjunction with the Transiting Exoplanet Survey Satellite (TESS) observations, to analyse the high-frequency pulsation in detail. We find a triplet that is split by the rotation frequency of the star (νrot = 0.3756 d−1; Prot = 2.66 d) and present both distorted dipole and distorted quadrupole mode models. We show that the pulsation frequency, 150.9898 d−1 (Ppuls = 9.54 min), is greater than the acoustic cut-off frequency. We utilize 27 high-resolution ($R\simeq 65\, 000$), high signal-to-noise ratio (∼120) spectra to provide new orbital parameters for this, the only known roAp star to be in a short-period binary (Porb = 93.266 d). We find the system to be more eccentric than previously thought, with e = 0.317, and suggest the companion is a mid-F to early-K star. We find no significant trend in the average pulsation mode amplitude with time, as measured by TESS, implying that the companion does not have an effect on the pulsation in this roAp star. We suggest further photometric observations of this star, and further studies to find more roAp stars in close binaries to characterize how binarity may affect the detection of roAp pulsations.

scholarly journals Radial Velocity Studies of roAp stars: Rotational Modulation in HR 1217

2002 ◽  
Vol 185 ◽  
pp. 300-301 ◽  
Author(s):  
A.P. Hatzes ◽  
D. Mkrtichian ◽  
A. Kanaan
Keyword(s):  
Radial Velocity ◽  
Broad Band ◽  
Rotation Period ◽  
Echelle Spectrograph ◽  
Preliminary Results ◽  
Rotational Modulation ◽  
Roap Star

AbstractWe present the preliminary results of our analysis of the precise radial velocity (RV) measurements of the roAp star HR1217. We have obtained over 2000 spectra of this star (54 hours of coverage) covering a complete rotation period using the 2-d coude echelle spectrograph of the McDonald Observatory’s 2.7m telescope. Our RV data show rotational modulation in both the amplitude and phase of the pulsations. The broad-band (covering 110 Å) RV semi-amplitudes of the f2 mode (=2.65 mHz) varied in the range of 25 m s–1 to 200 m s–1.

scholarly journals Bisector Velocities of Hα in the roAp Star α Cir: Probing the Principal Pulsation Mode

1998 ◽  
Vol 185 ◽  
pp. 309-310
Author(s):  
I. K. Baldry ◽  
T. R. Bedding ◽  
M. Viskum ◽  
H. Kjeldsen ◽  
S. Frandsen
Keyword(s):  
Dipole Mode ◽  
Principal Mode ◽  
Pulsation Mode ◽  
Roap Star

α Circini is the brightest of the known rapidly oscillating Ap (roAp) stars. Previous observations of this star in photometry (Kurtz et al. 1994) have shown that it has one dominant pulsation mode, which is a pure oblique dipole mode (ℓ = 1) with a frequency of 2442 μHz (P = 6.825 min). Kurtz et al. (1994) measured the amplitude of the principal mode to be 2.55 mmag (Strömgren v).

scholarly journals Velocity Variations of the roAp Star γ Equulei: Probing a puzzling pulsator

1995 ◽  
Vol 155 ◽  
pp. 347-348
Author(s):  
Jaymie M. Matthews ◽  
Sandra Scott
Keyword(s):  
Line Profile ◽  
Study Mode ◽  
Velocity Variations ◽  
Nonradial Mode ◽  
Roap Star

AbstractWe present a pulsational RV curve for γ Equ whose amplitude is about 200 m/s and period is roughly 11 minutes. These data, combined with rapid photometry and line-profile variations, are being used to identify the nonradial mode(s) and study mode growth/decay in this unusual star.

Quantitative analysis of the spectrum of the magnetic roAp star HD 83368 with “lithium” spots

2000 ◽  
Vol 44 (4) ◽  
pp. 235-245 ◽  
Author(s):  
A. V. Shavrina ◽  
N. S. Polosukhina ◽  
V. Tsymbal ◽  
V. Khalak
Keyword(s):  
Quantitative Analysis ◽  
Roap Star
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