Results 31 to 40 of about 151,165 (141)

Magnetic activity in the HARPS M dwarf sample

, 2017
Context. Atmospheric magnetic fields in stars with convective envelopes heat stellar chromospheres, and thus increase the observed flux in the Ca ...
Delfosse, X., X. Bonfils, T. Forveille, Astudillo-Defru, N., C. Lovis, X. Delfosse, Lovis, C., Bonfils, X., Forveille, T., Rameau, J., N. Astudillo-Defru, J. Rameau   +11 more
core   +1 more source

Fictions, Conditionals, and Stellar Astrophysics [PDF]

, 2013
This article argues in favour of an inferential role for fictions in scientific modelling. The argument proceeds by means of a detailed case study, namely models of the internal structure of stars in stellar astrophysics.
Suárez, Mauricio, Mauricio Suárez
core   +1 more source

Parker Solar Probe Observations of Proton Core‐Beam Distributions in Heliospheric Current Sheet Region: Quasilinear Instability Analysis Combined With Collisional Relaxation

Journal of Geophysical Research: Space Physics, Volume 131, Issue 4, April 2026.
Abstract Parker Solar Probe has been proven as instrumental for the observation of young solar wind. During the encounters E‐07 and E‐08, PSP recorded the core plus beaming protons crossing the heliospheric current Sheet region. When the observed PSP data is plotted in the temperature ratio versus parallel beta space, it is found that the occurrence ...
M. Rashid, P. H. Yoon, J. Huang, C. Salem, M. Sarfraz, S. Alnussirat, R. A. López, J. Seough, H. Xie, D. Larson, R. Livi   +10 more
wiley   +1 more source

Relations of Rotation and Chromospheric Activity to Stellar Age for FGK Dwarfs from Kepler and LAMOST

The Astrophysical Journal Supplement Series
The empirical relations between rotation period, chromospheric activity, and age can be used to estimate stellar age. To calibrate these relations, we present a catalog, including the masses and ages of 52,321 FGK dwarfs, 47,489 chromospheric activity ...
Lifei Ye, Shaolan Bi, Jinghua Zhang, Tiancheng Sun, Liu Long, Zhishuai Ge, Tanda Li, Xianfei Zhang, Xunzhou Chen, Yaguang Li, Jianzhao Zhou, Maosheng Xiang   +11 more
doaj   +1 more source

Only binary stars can help us actually SEE a stellar chromosphere

, 2007
Binary stars of the \u3b6 Aurigae type (eclipsing systems containing a cool giant plus a hot mainsequence star) offer a unique and highly effective method of probing a stellar chromosphere.
Griffin, R. Elizabeth
core   +1 more source

Physical Parameters and Activity Properties of K-type Stars Based on the LAMOST Spectral Survey

The Astrophysical Journal Supplement Series
K-type stars are important objects of our Galaxy. It is interesting to determine the stellar physical parameters and magnetic activity properties of K-type stars.
Zhiruo Zhang, Li-yun Zhang, Tianhao Su, Xianming L. Han, Prabhakar Misra, Qingfeng Pi, Hongpeng Lu   +6 more
doaj   +1 more source

Searching for Rotational X‐Ray Modulation on TIC 277539431

Astronomische Nachrichten, Volume 347, Issue 3, March 2026.
ABSTRACT TIC 277539431, a fast rotating M7 dwarf, was detected to host the highest latitude flare to date at 81°$$ {81}^{{}^{\circ}} $$. Magnetic activity like stellar flares occurring at high latitude indicate occurrence of coronal loops at these latitudes on fully‐convective M dwarfs. In contrast, sunspots usually occur below 30°$$ {30}^{{}^{\circ}} $
Desmond Dsouza, Katja Poppenhäger, Ekaterina Ilin   +2 more
wiley   +1 more source

Chromospheres of Coronal Stars [PDF]

, 1996
We summarize the main results obtained from the analysis of ultraviolet emission line profiles of coronal late-type stars observed with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope.
Brian E. Wood, Wood, Brian E., Jeffrey L. Linsky, Linsky, Jeffrey L.   +3 more
core   +1 more source

Magnetic Activity in M-type Stars Based on LAMOST DR11 and TESS Observations

The Astrophysical Journal Supplement Series
We have used 898,351 M-type stellar spectra released by Large Sky Area Multi-Object Fiber Spectroscopic Telescope DR11 to calculate the equivalent width of the Ca II infrared triplet (IRT) lines, the residual chromospheric emission, and the parameter ${R}
Linfeng Ren, Li-yun Zhang, Xianming L. Han, Tianhao Su, Wenjie Li, Yinpeng Wang, Prabhakar Misra   +6 more
doaj   +1 more source

In the Trenches of the Solar–Stellar Connection. VII. Wilson–Bappu 2022

The Astrophysical Journal Supplement Series, 2023
The Wilson–Bappu effect (WBE) is a remarkable correlation between the width of the chromospheric emission core of the Ca ii 3934 Å K line and stellar absolute visual magnitude over an astonishing range, from diminutive red dwarfs to bloated yellow ...
Thomas Ayres
doaj   +1 more source