Chromospheric activity and evolutionary age of the Sun and four solar twins

  title={Chromospheric activity and evolutionary age of the Sun and four solar twins},
  author={Marco Mittag and Klaus-Peter Schroder and Alexander Hempelmann and J. N. Gonz'alez-P'erez and J.H.M.M. Schmitt Hamburger Sternwarte and Universit{\`a}t Hamburg and Gojenbergsweg 112 and 21029 Hamburg and H Germany and Dep. de Astronomia and Univ. de Guanajuato and Mexico.},
  journal={arXiv: Solar and Stellar Astrophysics},
The activity levels of the solar-twin candidates HD 101364 and HD 197027 are measured and compared with the Sun, the known solar twin 18 Sco, and the solar-like star 51 Peg. Furthermore, the absolute ages of these five objects are estimated from their positions in the HR diagram and the evolutionary (relative) age compared with their activity levels. To represent the activity level of these stars, the Mount Wilson S-indices were used. To obtain consistent ages and evolutionary advance on the… 

Figures and Tables from this paper

Magnetic activity of the solar-like star HD 140538
The periods of rotation and activity cycles are among the most important properties of the magnetic dynamo thought to be operating in late-type, main-sequence stars. In this paper, we present a
Carrington cycle 24: the solar chromospheric emission in a historical and stellar perspective
We present the solar S-index record of cycle 24, obtained by the TIGRE robotic telescope facility and its high-resolution spectrograph HEROS (R$\approx$20,000), which measures the solar chromospheric
The Solar Twin Planet Search
Context. It is well known that the magnetic activity of solar-type stars decreases with age, but it is widely debated in the literature whether there is a smooth decline or if there is an early sharp
Magnetic Evolution and the Disappearance of Sun-Like Activity Cycles
After decades of effort, the solar activity cycle is exceptionally well characterized, but it remains poorly understood. Pioneering work at the Mount Wilson Observatory demonstrated that other
Fifteen years in the high-energy life of the solar-type star HD 81809. XMM-Newton observations of a stellar activity cycle
Aims. The data set of the long-term XMM-Newton monitoring program of HD 81809 is analyzed to study its X-ray cycle, to investigate if the latter is related to the chromospheric one, to infer the
An X-ray activity cycle on the young solar-like star ɛ Eridani
In 2015 we started the XMM-Newton monitoring of the young solar-like star Epsilon Eridani (440 Myr), one of the youngest solar-like stars with a known chromospheric CaII cycle. By analyzing the most
Solar chromospheric emission and magnetic structures from plages to intranetwork: Contribution of the very quiet Sun
Context. We need to establish a correspondence between the magnetic structures generated by models and usual stellar activity indexes to simulate radial velocity time series for stars less active
Modelling the solar twin 18 Scorpii
Context. Solar twins are objects of great interest in that they allow us to understand better how stellar evolution and structure are affected by variations of the stellar mass, age and chemical
Stellar Properties of Active G and K Stars: Exploring the Connection between Starspots and Chromospheric Activity
We gathered high resolution spectra for an ensemble of 55 bright active and inactive stars using the ARC 3.5 m Telescope Echelle Spectrograph at Apache Point Observatory ($R\approx$31,500). We
Benchmark ages for theGaiabenchmark stars
In the era of large-scale surveys of stars in the MilkyWay, stellar ages are crucial for studying the evolution of the Galaxy.But determining ages of field stars is notoriously difficult; therefore,


What do the Mt. Wilson stars tell us about solar activity
We relate the evolutionary status and mass of the Mt. Wilson project stars with the type and strength of stellar activity as established in decades of monitoring their chromospheric Ca II K line
The Activity and Variability of the Sun and Sun-like Stars. I. Synoptic Ca II H and K Observations
Synoptic measurements of activity in Sun-like stars have been performed continuously since 1966, and the largest set comes from the Mount Wilson HK project, in the form of the well-known S index. We
Chromospheric activities and kinematics for solar type dwarfs and subgiants : analysis of the activity distribution and the AVR
Aims. In this work we present chromospheric activity indices, kinematics, radial-velocities, and rotational velocities for more than 850 FGK-type dwarfs and subgiant stars in the southern hemisphere
The age of the Solar System redefined by the oldest Pb–Pb age of a meteoritic inclusion
The age of the Solar System can be defined as the time of formation of the first solid grains in the nebular disc surrounding the proto-Sun. This age is estimated by dating calcium‐aluminium-rich
The remarkable solar twin HIP 56948: a prime target in the quest for other Earths
Context. The Sun shows abundance anomalies relative to most solar twins. If the abundance peculiarities are due to the formation of inner rocky planets, that would mean that only a small fraction of
Hα and the Ca II H and K lines as activity proxies for late-type stars
Context. The main chromospheric activity indicator is the S index, which is the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied for stars from F
HR 6060: The Closest Ever Solar Twin?
The detailed analysis of the optical spectrum and evolutionary state of the G2 Va star HR 6060 shows this object to have atmospheric parameters, mass, chromospheric activity, and UBV colors
Fluxes in H\alpha and Ca II H and K for a sample of Southern stars
The main chromospheric activity indicator is the S index, which is esentially the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied basically for
Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog
We derive detailed theoretical models for 1074 nearby stars from the SPOCS (Spectroscopic Properties of Cool Stars) Catalog. The California and Carnegie Planet Search has obtained high-quality (R
Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
While the strong anticorrelation between chromospheric activity and age has led to the common use of the Ca II H and K emission index (R'_(HK) = L_(HK)/L_(bol)) as an empirical age estimator for