Lithium Abundance in Solar-Type Stars With Low Chromospheric Activity: Application to the Search for Maunder Minimum Analogs

Lubin, Dan; Tytler, David; Kirkman, David

doi:10.1088/0004-637x/716/1/766

Cited by 9 publications

(14 citation statements)

References 88 publications

(127 reference statements)

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“…As they discussed, however, their values may be overestimated for T eff 5800 K. The difficulties encountered when trying to constrain this parameter from the spectroscopic material routinely secured for abundance studies is illustrated by the fact that Fuhrmann (2004) estimated v sin i = 1.0 km s −1 only for HD 42618 by also adopting a calibrated macroturbulent velocity (ζ RT = 3.3 km s −1 in that particular case). A low-rotation rate is consistent with their low-activity levels (Hall et al 2009;Gray et al 2003;Isaacson & Fischer 2010;Lubin et al 2010). HD 43587 shows no evidence for activity cycles (Baliunas et al 1995) and has even been proposed to go through a Maunder-like minimum (Schröder et al 2012).…”

Section: Methods Of Analysismentioning

confidence: 58%

Abundance study of the two solar-analogue CoRoT targets HD 42618 and HD 43587 from HARPS spectroscopy

Morel

Rainer

Poretti

et al. 2013

A&A

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We present a detailed abundance study based on spectroscopic data obtained with HARPS of two solar-analogue main targets for the asteroseismology programme of the CoRoT satellite: HD 42618 and HD 43587. The atmospheric parameters and chemical composition are accurately determined through a fully differential analysis with respect to the Sun observed with the same instrumental set-up. Several sources of systematic errors largely cancel out with this approach, which allows us to narrow down the 1-σ error bars to typically 20 K in effective temperature, 0.04 dex in surface gravity, and less than 0.05 dex in the elemental abundances. Although HD 42618 fulfils many requirements for being classified as a solar twin, its slight deficiency in metals and its possibly younger age indicate that, strictly speaking, it does not belong to this class of objects. On the other hand, HD 43587 is slightly more massive and evolved. In addition, marked differences are found in the amount of lithium present in the photospheres of these two stars, which might reveal different mixing properties in their interiors. These results will put tight constraints on the forthcoming theoretical modelling of their solar-like oscillations and contribute to increase our knowledge of the fundamental parameters and internal structure of stars similar to our Sun.

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Section: Methods Of Analysismentioning

confidence: 58%

Abundance study of the two solar-analogue CoRoT targets HD 42618 and HD 43587 from HARPS spectroscopy

Morel

Rainer

Poretti

et al. 2013

A&A

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“…The comparison was made for the precise determinations of the Li content, but not for the estimations of the upper limits of the Li abundance. As marked in the study by Lubin et al (2010), which collected the determinations of the Li abundance, made in thirty studies by different authors and for various objects, for log A(Li) > 1.5 there is a relatively small dispersion in the Li abundance detections among various measurement programmes, while the scattering increases for lower log A(Li). The difference in log A(Li) is about 0.5-1 dex.…”

Section: Determination Of the LI Abundancementioning

confidence: 99%

Activity and the Li abundances in the FGK dwarfs

Mishenina

Soubiran

Kovtyukh

et al. 2012

A&A

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Aims. The aim of the present study is to determine the Li abundances for a large set of the FGK dwarfs and to analyse the connections between the Li content, stellar parameters, and activity. Methods. The atmospheric parameters, rotational velocities and the Li abundances were determined from a homogeneous collection of the echelle spectra with high resolution and a high signal-to-noise ratio. The rotational velocities v sin i were determined by calibrating the cross-correlation function. The effective temperatures T eff were estimated by the line-depth ratio method. The surface gravities log g were computed by two methods: the iron ionization balance and the parallax. The LTE Li abundances were computed using synthetic spectra method. The behaviour of the Li abundance was examined in correlation with T eff , [Fe/H], as well as with v sin i and the level of activity in three stellar groups of the different temperature range. Results. The stellar parameters and the Li abundances are presented for 150 slow rotating stars of the lower part of the main sequence. The studied stars show a decline in the Li abundance with decreasing temperature T eff and a significant spread, which should be due to the difference of age of stars. The correlations between the Li abundances, rotational velocities v sin i, and the level of the chromospheric activity were discovered for the stars with 6000 > T eff > 5700 K, and it is tighter for the stars with 5700 > T eff > 5200 K. The target stars with T eff < 5200 K do not show any correlation between log A(Li) and v sin i. The relationship between the chromospheric and coronal fluxes in active with detected Li as well as in less active stars gives a hint that there exist different conditions in the action of the dynamo mechanism in those stars. Conclusions. We found that the Li-activity correlation is evident only in a restricted temperature range and the Li abundance spread seems to be present in a group of low chromospheric activity stars that also show a broad spread in the chromospheric vs. coronal activity.

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“…Wright (2004) suggested that the majority of ''Maunder minimum'' identifications were actually of more evolved stars, and ''there is no unambiguous identification of another star in a Maunder minimum state''. At the very least, such states appear to be rare (see also Lubin et al 2010Lubin et al , 2012), so we must identify and observe a large number of solar analogs in order to unambiguously detect any.…”

Section: Introductionmentioning

confidence: 99%

Rotation, activity, and stellar obliquities in a large uniform sample ofKeplersolar analogs

Buzasi

Lezcano

Preston³

2016

J. Space Weather Space Clim.

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In this study, we undertook a deep photometric examination of a narrowly-defined sample of solar analogs in the Kepler field, with the goals of producing a uniform and statistically meaningful sample of such stars, comparing the properties of planet hosts to those of the general stellar population, and examining the behavior of rotation and photometric activity among stars with similar overall physical parameters. We successfully derived photometric activity indicators and rotation periods for 95 planet hosts (Kepler objects of interest [KOIs]) and 954 solar analogs without detected planets; 573 of these rotation periods are reported here for the first time. Rotation periods average roughly 20 d, but the distribution has a wide dispersion, with a tail extending to P > 35 d which appears to be inconsistent with published gyrochronological relations. We observed a weak rotation-activity relation for stars with rotation periods less than about 12 d; for slower rotators, the relation is dominated by scatter. However, we are able to state that the solar activity level derived from Virgo data is consistent with the majority of stars with similar rotation periods in our sample. Finally, our KOI sample is consistently approximately 0.3 dex more variable than our non-KOIs; we ascribe the difference to a selection effect due to low orbital obliquity in the planet-hosting stars and derive a mean obliquity for our sample of v ¼ 6 þ5 À6 , similar to that seen in the solar system.

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Lithium Abundance in Solar-Type Stars With Low Chromospheric Activity: Application to the Search for Maunder Minimum Analogs

Cited by 9 publications

References 88 publications

Abundance study of the two solar-analogue CoRoT targets HD 42618 and HD 43587 from HARPS spectroscopy

Abundance study of the two solar-analogue CoRoT targets HD 42618 and HD 43587 from HARPS spectroscopy

Activity and the Li abundances in the FGK dwarfs

Rotation, activity, and stellar obliquities in a large uniform sample ofKeplersolar analogs

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