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Related papers: Population and dynamical state of the eta Chamaele…

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Eta Chamaeleontis is a unique young (~9 Myr) association with 18 systems concentrated in a radius of ~35 arcmin, i.e. 1pc at the cluster distance of 97pc. No other members have been found up to 1.5 degrees from the cluster centre. The…

Astrophysics · Physics 2009-11-13 E. Moraux , W. Lawson , C. Clarke

The eta Chamaeleontis star cluster is one of the most important nearby groupings of pre-main sequence (PMS) stars. With accurately known distance, compact structure and highly-coeval intermediate-aged population, the eta Cha cluster is an…

Astrophysics · Physics 2007-05-23 W. A. Lawson

A limited-area survey of the eta Chamaeleontis cluster has identified 2 new late-type members. The more significant of these is ECHA J0843.3-7905 (= IRAS F08450-7854), a slowly-rotating (P = 12 d) M2 classical T Tauri (CTT) star with a…

Astrophysics · Physics 2009-11-07 Warrick A. Lawson , Lisa A. Crause , Eric E. Mamajek , Eric D. Feigelson

We have identified several lithium-rich low-mass (0.08<M<0.3 Msun). stars within 5.5 deg of the young open cluster Eta Chamaeleontis, nearly four times the radius of previous search efforts. We propose 4 new probable cluster members and 3…

Solar and Stellar Astrophysics · Physics 2010-12-14 Simon J. Murphy , Warrick A. Lawson , Michael S. Bessell

We have identified several lithium-rich low-mass (0.08<M<0.3 Msun) stars within 5.5 deg of the young open cluster Eta Chamaeleontis, nearly four times the radius of previous search efforts. Of these stars we propose 4 new probable cluster…

Solar and Stellar Astrophysics · Physics 2015-05-19 Simon J. Murphy , Warrick A. Lawson , Michael S. Bessell

We present IRS spectra and revised MIPS photometry for the 18 members of the Eta Chamaeleontis cluster. Aged 8 Myr, the Eta Cha cluster is one of the few nearby regions within the 5-10 Myr age range, during which the disk fraction decreases…

In the scope of the star formation process, it is unclear how the environment shapes the initial mass function (IMF). While observations of open clusters propose a universal picture for the IMF from the substellar domain up to a few solar…

Solar and Stellar Astrophysics · Physics 2015-06-15 Christophe Becker , Estelle Moraux , Gaspard Duchêne , Thomas Maschberger , Warrick Lawson

We present a study of flux-calibrated low-resolution optical spectroscopy of ten stars belonging to eight systems in the ~ 5 Myr-old Epsilon Chamaeleontis (Eps Cha) pre-main-sequence (PMS) star cluster. Using synthetic broadband colours,…

Astrophysics · Physics 2009-11-13 A-Ran Lyo , Warrick A. Lawson , M. S. Bessell

A young, nearby compact aggregate of X-ray emitting pre-main sequence stars was recently discovered in the vicinity of eta Cha (B8V). In this paper, we further investigate this cluster: its membership, its environs and origins. ROSAT HRI…

Astrophysics · Physics 2009-10-31 Eric E. Mamajek , Warrick A. Lawson , Eric D. Feigelson

We present new L' (3.8-micron) observations of stars in the nearby (~97 pc) young (~6 Myr) compact cluster around eta Chamaeleontis, obtained with the European Southern Observatory's Very Large Telescope in Paranal, Chile. Our data,…

Astrophysics · Physics 2009-11-11 Karl E. Haisch , Ray Jayawardhana , Joao Alves

We have carried out a sensitive high-resolution imaging survey of stars in the young (6-8 Myr), nearby (97 pc) compact cluster around eta Chamaeleontis to search for stellar and sub-stellar companions. Given its youth and proximity, any…

We have identified three faint new members of the eta Chamaeleontis cluster. Spectral types of the new members are estimated to be ~M5 based on their TiO band strengths and broadband colors. With an age of 5-8 Myr for the cluster, masses of…

Astrophysics · Physics 2009-11-10 Inseok Song , B. Zuckerman , M. S. Bessell

We report the outcome of the deep optical/infrared photometric survey of the central region (33 X 33 arcmin or 0.9 pc^2) of the eta Chamaeleontis pre-main sequence star cluster. The completeness limits of the photometry are I = 19.1, J =…

Astrophysics · Physics 2009-11-11 A-Ran Lyo , Inseok Song , Warrick A. Lawson , M. S. Bessell , B. Zuckerman

The nearby young open cluster eta Chamaeleontis has been observed by eROSITA/SRG during its CalPV phase for 150 ks. The eROSITA data were taken in the field-scan mode, an observing mode of Spectrum-Roentgen-Gamma (SRG) that follows a…

Solar and Stellar Astrophysics · Physics 2021-06-29 J. Robrade , S. Czesla , S. Freund , J. H. M. M. Schmitt , P. C. Schneider

We present multi-epoch medium-resolution observations of two M4.5 candidate members in the halo of the ~8 Myr Eta Chamaeleontis open cluster. Over six months of observations both stars exhibited variations in their H-alpha line profiles on…

Solar and Stellar Astrophysics · Physics 2015-05-20 Simon J. Murphy , Warrick A. Lawson , Michael S. Bessell , Daniel D. R. Bayliss

We have analyzed JHKL observations of the stellar population of the ~9 Myr-old eta Chamaeleontis cluster. Using infrared (IR) colour-colour and colour-excess diagrams, we find the fraction of stellar systems with near-IR excess emission is…

We present a comprehensive investigation of the Epsilon Chamaeleontis association (Epsilon Cha), one of several young moving groups spread across the southern sky. We re-assess the putative membership of Epsilon Cha using the best-available…

Solar and Stellar Astrophysics · Physics 2015-06-16 Simon J. Murphy , Warrick A. Lawson , Michael S. Bessell

We present the outcomes of a Chandra X-ray Observatory snapshot study of five nearby Herbig Ae/Be (HAeBe) stars which are kinematically linked with the Oph-Sco-Cen Association (OSCA). Optical photometric and spectroscopic followup was…

Astrophysics · Physics 2009-11-10 Eric D. Feigelson , Warrick A. Lawson , Gordon P. Garmire

Nearby associations are ideal regions to study coeval samples of protoplanetary and debris disks down to late M-type stars. Those aged 5-10,Myrs, where most of the disk should have already dissipated forming planets, are of particular…

Earth and Planetary Astrophysics · Physics 2023-10-05 V. Roccatagliata , A. Sicilia-Aguilar , M. Kim , J. Campbell-White , M. Fang , S. J. Murphy , S. Wolf , W. A. Lawson , Th. Henning , J. Bouwman

We present IRAC 3.6, 4.5, 5.8 and 8 micron photometry for the 17 A, K and M type members of the Eta Chameleontis association. These data show infrared excesses toward six of the 15 K and M stars, indicating the presence of circumstellar…

Astrophysics · Physics 2009-11-13 S. T. Megeath , L. Hartmann , K. L. Luhman , G. G. Fazio
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