Deep XMM-Newton observation of the Eta Chamaleontis cluster

Abstract

The members of the Eta Chamaleontis cluster are in an evolutionary stage in which disks are rapidly evolving. It also presents some peculiarities, such as the large fraction of binaries and accretion disks, probably related with the cluster formation process. Its proximity makes this stellar group an ideal target for studying the relation between X-ray emission and those stellar parameters. The main objective of this work is to determine general X-ray properties of the cluster members in terms of coronal temperature, column density, emission measure, X-ray luminosity and variability. We also aim to establish the relation between the X-ray luminosity of these stars and other stellar parameters, such as binarity and presence of accretion disks. A study of flare energies for each flare event and their relation with some stellar parameters is also performed. We used proprietary data from a deep XMM-Newton observation pointed at the core of the Eta Chamaleontis cluster. Specific software for the reduction of XMM-Newton data was used for the analysis of our observation. For the detection of sources, we used the wavelet-based code PWDetect. General coronal properties were derived from plasma model fitting. We also determined variability of the Eta Chamaleontis members in the EPIC field-of-view. A total of six flare-like events were clearly detected in five different stars. For them, we derived coronal properties during the flare events and pseudo-quiescent state separately. In our observations, stars that underwent a flare event have higher X-ray luminosities in the pseudo-quiescent state than cluster members with similar spectral type with no indications of flaring, independently whether they have an accretion disk or not. Observed flare energies are typical of both pre-main and main-sequence M stars. We detected no difference between flare energies of stars with and without an accretion disk.

Accepted for publication in Astronomy and Astrophysics. 12 pages, 30 individual figures

References in corpus (15)

• The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)
• Accretion Disks around Young Stars: Lifetimes, Disk Locking and Variability
• Pre-main sequence spectroscopic binaries suitable for VLTI observations
• On the origin of the X-ray emission from Herbig Ae/Be stars
• A statistical analysis of X-ray variability in pre-main sequence objects of the Taurus Molecular Cloud
• X-ray emission from dense plasma in CTTSs: Hydrodynamic modeling of the accretion shock
• Further X-ray detections of Herbig stars
• A deep photometric survey of the eta Chamaeleontis cluster down to the brown dwarf - planet boundary
• Spectral properties of X-ray bright variable sources in the Taurus Molecular Cloud
• The stellar content of the XMM-Newton Bright Serendipitous Survey
• eta Chameleontis: abnormal initial mass function or dynamical evolution?
• New deep XMM-Newton observations to the west of the sigma Orionis cluster
• HRC-I/Chandra X-ray observations towards sigma Orionis
• X-ray flares on the UV Ceti-type star CC Eridani: a "peculiar" time-evolution of spectral parameters
• Discovery of non-radial pulsations in the spectroscopic binary Herbig Ae star RS Cha

Cited by in corpus (10)

• GASPS - a Herschel survey of gas and dust in Protoplanetary Disks: Summary and Initial Statistics
• LACEwING: A New Moving Group Analysis Code
• NUV Excess in Slowly Accreting T Tauri Stars: Limits Imposed by Chromospheric Emission
• The unusual protoplanetary disk around the T Tauri star ET Cha
• Evolution of X-ray and FUV Disk-Dispersing Radiation Fields
• Simultaneous Kepler/K2 and XMM-Netwon observations of superflares in the Pleiades
• Direct Measurement of Interstellar Extinction Toward Young Stars Using Atomic Hydrogen Lyman-$\alpha$ Absorption
• The 1600 Angstrom Emission Bump in Protoplanetary Disks: A Spectral Signature of H${}_2$O Dissociation
• A comprehensive study of NGC 2023 with XMM-Newton and Spitzer
• Star formation history of Canis Major OB1 - II. A bimodal X-ray population revealed by XMM-Newton