Lithium abundance in field K and M dwarfs

Zboril, M.; Byrne, P. B.; Rolleston, W. R. J.

doi:10.1093/mnras/284.3.685

Cited by 18 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3) For K-type stars the total equivalent width of these Fe  lines is 0.14 ± 0.04 Å (Zboril et al 1997). When we take into account the overestimation for W(Li), the points in Fig.…”

Section: Hr Diagram and Physical Parameters Of The Pms Starsmentioning

confidence: 96%

Search for new T Tauri stars in the Cepheus-Cassiopeia region

Tachihara¹,

Neuhäuser²,

Kun

et al. 2005

A&A

View full text Add to dashboard Cite

Abstract. The Cepheus-Cassiopeia star-forming region has been searched for new T Tauri stars (TTSs) based on the ROSAT all sky survey (RASS). Optical spectroscopic observations were carried out toward 45 GSC stellar counterparts of RASS sources looking for the Li absorption line (6708 Å), a sign of youth. The detection of this line resulted in finding 11 to 16 new TTSs in this region. Using follow-up optical photometric observations and evolutionary models these Li-rich stars are revealed to be young low-mass stars. The most of the young stars are separated from the 13 CO molecular clouds by ∼10 pc, significantly more than in Chamaeleon. A group of the new TTSs are isolated from the CO clouds and distributed inside the previously determined CO void. Possible formation scenarios including the interaction with the supernova shock for the isolated TTSs are discussed.Key words. ISM: clouds -ISM: molecules -stars: formation -stars: late-type -stars: pre-main sequence -X-rays: stars Introduction: The Cepheus-Cassiopeia star-forming regionLarge-scale X-ray surveys are a powerful method to search for T Tauri stars (TTSs) that are widely spread over starforming regions (SFRs). Spectroscopic follow-up observations towards the X-ray sources found by the ROSAT X-ray satellite have been carried out in nearby SFRs such as Taurus ), Chamaeleon (Alcalá et al. 1995), and Lupus (Wichmann et al. 1997, most of which are thought to belong to the Gould belt. These surveys found a large number of T Tauri stars (see Neuhäuser 1997 for a review). One of the interesting results of the X-ray selected TTS surveys is that a large number of TTSs have been found far away from the molecular clouds. Because of their youth ( < ∼ a few ×10 7 yr), they are supposed to be distributed within ∼10 pc of their birthplaces. Nonetheless, many so-called "isolated TTSs", separated from the molecular clouds by more than a few tens of pc, are found, for example, south of the Taurus and η Cha clusters (Mamajek et al. 1999), even though many of those south of Taurus were later reported to be active binaries (Torres et al. 2002). Recent studies suggest that such isolation is likely caused by in situ star formation in small clouds and their subsequent rapid dissipation (e.g., Mizuno et al. 1998;Tachihara et al. 2001).Cepheus-Cassiopeia (Cep-Cas) is a nearby SFR located at l ∼ 100 • -140 • and b ∼ 5 • -25 • . The region has been surveyed extensively for molecular clouds in 12 CO by Grenier et al. (1989) who found a total molecular mass of ∼10 5 M . They reported that the cloud distribution shows a CO void which contains an excess of soft X-rays and radio continuum, suggesting a hot bubble created by a supernova. A distance estimation to several dark clouds have been carried out by measuring the colour excess or utilizing star counts (Kun & Prusti 1993;Kun et al. 1994;Kun 1998;Obayashi et al. 1998). Yonekura et al. (1997) surveyed the region in 13 CO and detected 188 distinct molecular clouds. They obtained different radial velocities suggesting that layers at d...

show abstract

“…3) For K-type stars the total equivalent width of these Fe  lines is 0.14 ± 0.04 Å (Zboril et al 1997). When we take into account the overestimation for W(Li), the points in Fig.…”

Section: Hr Diagram and Physical Parameters Of The Pms Starsmentioning

confidence: 96%

Search for new T Tauri stars in the Cepheus-Cassiopeia region

Tachihara¹,

Neuhäuser²,

Kun

et al. 2005

A&A

View full text Add to dashboard Cite

show abstract

“…Lithium abundances are from Duncan (1981), Soderblom & Mayor (1993b), Soderblom et al (1993), Favata et al (1993), Pasquini, Liu, & Pallavicini (1994), Favata, Micela, & Sciorino (1996), Zboril, Byrne, &Rolleston (1997), andFavata et al (1997).…”

Section: Rotational Velocities ( ) Are Taken From Soderblom and V Sin Imentioning

confidence: 99%

Nearby Young Solar Analogs. I. Catalog and Stellar Characteristics

Gaidos

1998

PUBL ASTRON SOC PAC

View full text Add to dashboard Cite

ABSTRACT. We present a catalog of 38 young solar analogs within 25 pc, stars that are uniquely well suited for observations of their circumstellar environments to improve our understanding of conditions within the solar system during the Hadean/early Archean eons (prior to 3.8 Gyr ago). These G and early K stars were selected from the Hipparcos astrometric catalog based on lack of known stellar companions within 800 AU, bolometric luminosities close to that of the zero-age Sun and consistent with the zero-age main sequence, and ROSAT X-ray luminosities commensurate with the higher rotation rate and level of dynamo-driven activity in solar-mass stars less than 0.8 Gyr old. While many of these objects have been previously identified, this sample is novel in two respects: The selection criteria specifically consider the planetary environment, and the selection is uniform and all-sky. The X-ray emission from these young analogs is spectrally soft and consistent with a coronal origin. Calcium H and K emission, rotation periods, lithium abundances, and kinematics support an age range of 0.2-0.8 Gyr for most of these stars. Three stars have exceptionally high space motions with respect to the local standard of rest and may be old disk or halo stars that are anomalously X-ray luminous.

show abstract

“…For HIP 37563, we measured 125 m for Li l6708. Wichmann et al (2003) and Cutispoto et al (2002) Zboril et al (1997); it is a triple system (Martín 2003). HIP 117410 is a 1Љ Hipparcos binary.…”

Section: Introductionmentioning

confidence: 99%

The Carina-Near Moving Group

Zuckerman

Bessell

Song

et al. 2006

ApJ

111

View full text Add to dashboard Cite

We identify a group of ~20 co-moving, mostly southern hemisphere, ~200 Myr old stars near Earth. Of the stars likely to be members of this Carina-Near Moving Group, in either its nucleus (~30 pc from Earth) or surrounding stream, all but 3 are plausible members of a multiple star system. The nucleus is (coincidentally) located quite close to the nucleus of the AB Doradus moving group notwithstanding that the two groups have substantially different ages and Galactic space motions, UVW.Comment: 9 pages, 1 table, 2 figures. Accepted in ApJ

show abstract

Lithium abundance in field K and M dwarfs

Cited by 18 publications

References 0 publications

Search for new T Tauri stars in the Cepheus-Cassiopeia region

Search for new T Tauri stars in the Cepheus-Cassiopeia region

Nearby Young Solar Analogs. I. Catalog and Stellar Characteristics

The Carina-Near Moving Group

Contact Info

Product

Resources

About