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Related papers: Measuring Accretion in Young Substellar Objects: A…

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We present a method of determining lower limits on the masses of pre-main-sequence (PMS) stars and so constraining the PMS evolutionary tracks. This method uses the red-shifted absorption feature observed in some emission-line profiles of T…

Context. The lack of knowledge of photospheric parameters and the level of chromospheric activity in young low-mass pre-main sequence stars introduces uncertainties when measuring mass accretion rates in accreting (Class II) Young Stellar…

Astrophysics of Galaxies · Physics 2015-06-12 C. F. Manara , L. Testi , E. Rigliaco , J. M. Alcala , A. Natta , B. Stelzer , K. Biazzo , E. Covino , S. Covino , G. Cupani , V. D'Elia , S. Randich

A large fraction of white dwarfs are accreting or have recently accreted rocky material from their planetary systems, thereby polluting their atmospheres with elements heavier than helium. In recent years, the quest for mechanisms that can…

Solar and Stellar Astrophysics · Physics 2021-12-08 Simon Blouin , Siyi Xu

White dwarfs stars are known to be polluted by their active planetary systems, but little attention has been paid to the accretion of wind from low-mass companions. The capture of stellar or substellar wind by white dwarfs is one of few…

Solar and Stellar Astrophysics · Physics 2023-07-05 N. Walters , J. Farihi , P. Dufour , J. S. Pineda , R. G. Izzard

The science case on studies of accretion and outflows in low-mass ($<$1.5 $M_{\odot}$) young stellar objects (YSOs) with the new CUBES instrument is presented. We show the need for a high-sensitivity, near-ultraviolet (NUV) spectrograph…

Solar and Stellar Astrophysics · Physics 2022-03-30 J. M. Alcalá , G. Cupani , C. J. Evans , M. Franchini , B. Nisini

We used the WINERED spectrograph to perform near-infrared high-resolution spectroscopy (resolving power $R = 28$,000) of 13 young intermediate-mass stars in the Taurus star-forming region. Based on the presence of near- and mid-infrared…

Using the Hubble Space Telescope, the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory, and the Spitzer Space Telescope, we have performed deep imaging from 0.8 to 8 um of the southern subcluster in the Chamaeleon I…

We report the detection of seven low mass companions to intermediate-mass stars (SpT B/A/F; $M$$\approx$1.5-4.5 solar masses) in the Scorpius-Centaurus Association using nonredundant aperture masking interferometry. Our newly detected…

Using the Hectochelle multifiber spectrograph, we have obtained high-resolution (R~34,000) spectra in the Halpha region for a large number of stars in the 4 Myr-old cluster Tr 37, containing 146 previously known members and 26 newly…

This paper explores how the stochastic accretion of planetesimals onto white dwarfs would be manifested in observations of their atmospheric pollution. Archival observations of pollution levels for unbiased samples of DA and non-DA white…

Earth and Planetary Astrophysics · Physics 2015-06-18 M. C. Wyatt , J. Farihi , J. E. Pringle , A. Bonsor

Two new magnetic white dwarf accretion binaries with extremely low mass-transfer rates have been discovered in the course of the Sloan Digital Sky Survey. Measured magnetic fields are 42 MG and 57 MG, and one system orbits with a period of…

We aim at characterizing the accretion properties of several hundred members of the star-forming cluster NGC 2264 (3 Myr). We performed a deep u,g,r,i mapping and a simultaneous u+r monitoring of the region with CFHT/MegaCam in order to…

We present mid-infrared spectra and photometry of thirteen redshift 0.4<z<1 dust-reddened quasars obtained with Spitzer IRS and MIPS. We compare properties derived from their infrared spectral energy distributions (intrinsic AGN luminosity…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-27 Tanya Urrutia , Mark Lacy , Henrik Spoon , Eilat Glikman , Andreea Petric , Bernhard Schulz

Mass accretion from the circumstellar disk onto the protostar is a fundamental process during star formation. Measuring the mass accretion rate is particularly challenging for stars belonging to binary systems, because it is often difficult…

Solar and Stellar Astrophysics · Physics 2022-04-06 Eleonora Fiorellino , Sunkyung Park , Ágnes Kóspál , Péter Ábrahám

The 2-Micron All Sky Survey (2MASS) (Skrutskie et al. 1997) and the DEep Near Infrared Survey of the southern sky (DENIS) (Epchtein et al. 1997) have revealed a heretofore unknown population of free brown dwarfs that has extended the local…

Astrophysics · Physics 2009-10-31 S. J. Peale

Polluted white dwarfs serve as astrophysical mass spectrometers - their photospheric abundances are used to infer the composition of planetary objects that accrete onto them. We show that due to asymmetries in the accretion process, the…

Earth and Planetary Astrophysics · Physics 2022-11-30 Marc G. Brouwers , Amy Bonsor , Uri Malamud

We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II] and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass outflow rates. Thereby we…

The star-forming regions in Chamaeleon are one of the nearest (distance ~165 pc) and youngest (age ~2 Myrs) conglomerates of recently formed stars and the ideal target for population studies of star formation. We investigate a total of 16…

Solar and Stellar Astrophysics · Physics 2015-06-04 N. Vogt , T. O. B. Schmidt , R. Neuhäuser , A. Bedalov , T. Roell , A. Seifahrt , M. Mugrauer

Diagnostics of electron temperature (T_e), electron density (n_e), and hydrogen column density (N_H) from the Chandra High Energy Transmission Grating spectrum of He-like Ne IX in TW Hydrae (TW Hya), in conjunction with a classical…

Solar and Stellar Astrophysics · Physics 2015-06-12 N. S. Brickhouse , S. R. Cranmer , A. K. Dupree , H. M. Günther , G. J. M. Luna , S. J. Wolk