Isolating Red Giant Stars in M31's Elusive Outer Spheroid

1998 ◽  
Vol 116 (2) ◽  
pp. 707-722 ◽  
Author(s):  
David B. Reitzel ◽  
Puragra Guhathakurta ◽  
Andrew Gould
Keyword(s):  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant

Ellipsoidal Variability and Long Secondary Periods in MACHO Red Giant Stars

2006 ◽  
Vol 650 (1) ◽  
pp. L55-L58 ◽  
Author(s):  
A. Derekas ◽  
L. L. Kiss ◽  
T. R. Bedding ◽  
H. Kjeldsen ◽  
P. Lah ◽  
...  
Keyword(s):  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant

Dust clouds around red giant stars: Evidence of sublimating comet disks?

Icarus ◽  
1989 ◽  
Vol 81 (1) ◽  
pp. 24-30 ◽  
Author(s):  
John J. Matese ◽  
Daniel P. Whitmire ◽  
Ray T. Reynolds
Keyword(s):  
Giant Stars ◽  
Dust Clouds ◽  
Red Giant Stars ◽  
Red Giant

The chemical compositions of red giant stars

1989 ◽  
Author(s):  
Verne V. Smith
Keyword(s):  
Chemical Compositions ◽  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant

scholarly journals They Might Be Giants: An Efficient Color-based Selection of Red Giant Stars

2018 ◽  
Vol 861 (2) ◽  
pp. L16 ◽  
Author(s):  
Charlie Conroy ◽  
Ana Bonaca ◽  
Rohan P. Naidu ◽  
Daniel J. Eisenstein ◽  
Benjamin D. Johnson ◽  
...  
Keyword(s):  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant ◽  
Selection Of

scholarly journals Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars

2013 ◽  
Vol 559 ◽  
pp. A102 ◽  
Author(s):  
V. Dobrovolskas ◽  
A. Kučinskas ◽  
M. Steffen ◽  
H.-G. Ludwig ◽  
D. Prakapavičius ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant

scholarly journals Flare-Like Activity of Red Giant Stars

1983 ◽  
Vol 71 ◽  
pp. 251-254 ◽  
Author(s):  
Robert E. Stencel
Keyword(s):  
Surface Activity ◽  
Magnetic Surface ◽  
Low Gravity ◽  
Giant Stars ◽  
Cool Stars ◽  
Red Giant Stars ◽  
Red Giant

ABSTRACTEvidence for magnetic surface activity among cool stars of low gravity is discussed.

Flare-Like Activity of Red Giant Stars

1983 ◽  
pp. 251-254 ◽  
Author(s):  
Robert E. Stencel
Keyword(s):  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant

scholarly journals On using dipolar modes to constrain the helium glitch in red giant stars

2020 ◽  
Vol 497 (1) ◽  
pp. 1008-1014
Author(s):  
G Dréau ◽  
M S Cunha ◽  
M Vrard ◽  
P P Avelino
Keyword(s):  
Acoustic Waves ◽  
Acoustic Mode ◽  
Stellar Model ◽  
Red Giants ◽  
Dipole Mode ◽  
Structural Variations ◽  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant ◽  
Additional Constraints

ABSTRACT The space-borne missions CoRoT and Kepler have revealed numerous mixed modes in red giant stars. These modes carry a wealth of information about red giant cores, but are of limited use when constraining rapid structural variations in their envelopes. This limitation can be circumvented if we have access to the frequencies of the pure acoustic dipolar modes in red giants, i.e. the dipole modes that would exist in the absence of coupling between gravity and acoustic waves. We present a pilot study aimed at evaluating the implications of using these pure acoustic mode frequencies in seismic studies of the helium structural variation in red giants. The study is based on artificial seismic data for a red giant branch stellar model, bracketing seven acoustic dipole radial orders around νmax. The pure acoustic dipole-mode frequencies are derived from a fit to the mixed-mode period spacings and then used to compute the pure acoustic dipole-mode second differences. The pure acoustic dipole-mode second differences inferred through this procedure follow the same oscillatory function as the radial-mode second differences. The additional constraints brought by the dipolar modes allow us to adopt a more complete description of the glitch signature when performing the fit to the second differences. The amplitude of the glitch retrieved from this fit is 15${{\ \rm per\ cent}}$ smaller than that from the fit based on the radial modes alone. Also, we find that thanks to the additional constraints, a bias in the inferred glitch location, found when adopting the simpler description of the glitch, is avoided.

scholarly journals Three-dimensional hydrodynamical simulations of surface convection in red giant stars

2007 ◽  
Vol 469 (2) ◽  
pp. 687-706 ◽  
Author(s):  
R. Collet ◽  
M. Asplund ◽  
R. Trampedach
Keyword(s):  
Three Dimensional ◽  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant ◽  
Hydrodynamical Simulations ◽  
Surface Convection

scholarly journals The Aarhus red giants challenge

2020 ◽  
Vol 635 ◽  
pp. A165
Author(s):  
J. Christensen-Dalsgaard ◽  
V. Silva Aguirre ◽  
S. Cassisi ◽  
M. Miller Bertolami ◽  
A. Serenelli ◽  
...  
Keyword(s):  
Careful Consideration ◽  
Red Giants ◽  
Giant Stars ◽  
Observational Accuracy ◽  
Low Degree ◽  
Red Giant Stars ◽  
Red Giant ◽  
Internal Properties ◽  
Oscillation Frequencies ◽  
Oscillation Properties

Contact. The large quantity of high-quality asteroseismic data that have been obtained from space-based photometric missions and the accuracy of the resulting frequencies motivate a careful consideration of the accuracy of computed oscillation frequencies of stellar models, when applied as diagnostics of the model properties. Aims. Based on models of red-giant stars that have been independently calculated using different stellar evolution codes, we investigate the extent to which the differences in the model calculation affect the model oscillation frequencies and other asteroseismic diagnostics. Methods. For each of the models, which cover four different masses and different evolution stages on the red-giant branch, we computed full sets of low-degree oscillation frequencies using a single pulsation code and, from these frequencies, typical asteroseismic diagnostics. In addition, we carried out preliminary analyses to relate differences in the oscillation properties to the corresponding model differences. Results. In general, the differences in asteroseismic properties between the different models greatly exceed the observational precision of these properties. This is particularly true for the nonradial modes whose mixed acoustic and gravity-wave character makes them sensitive to the structure of the deep stellar interior and, hence, to details of their evolution. In some cases, identifying these differences led to improvements in the final models presented here and in Paper I; here we illustrate particular examples of this. Conclusions. Further improvements in stellar modelling are required in order fully to utilise the observational accuracy to probe intrinsic limitations in the modelling and improve our understanding of stellar internal physics. However, our analysis of the frequency differences and their relation to stellar internal properties provides a striking illustration of the potential, in particular, of the mixed modes of red-giant stars for the diagnostics of stellar interiors.

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