New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit

Baraffe, I.; Homeier, D.; Allard, F.; Chabrier, G.

doi:10.1051/0004-6361/201425481

Cited by 1,603 publications

(2,674 citation statements)

References 32 publications

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“…We first interpolate the values of each physical parameter such as T eff from the BHAC15 evolutionary tracks (Baraffe et al 2015) onto uniform, 2-d grids in log(mass) and log(L bol ), using grid steps of 0.01 dex in both axes. We draw random, normally distributed values of the individual component's bolometric fluxes for each step in our MCMC chains.…”

Section: Evolutionary Model-derived Propertiesmentioning

confidence: 99%

High-Precision Radio and Infrared Astrometry of LSPM J1314+1320ab. Ii. Testing Pre-Main-Sequence Models at the Lithium Depletion Boundary With Dynamical Masses

Dupuy

Forbrich

Rizzuto

et al. 2016

ApJ

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We present novel tests of pre-main-sequence models based on individual dynamical masses for the M7 binary LSPMJ1314+1320AB. Joint analysis of Keck adaptive optics astrometric monitoring along with Very Long Baseline Array radio data from a companion paper yield component masses of 92.8±0.6 M Jup (0.0885±0.0006 M ☉ ) and 91.7±1.0 M Jup (0.0875±0.0010 M ☉ ) and a parallactic distance of 17.249±0.013 pc. We find component luminosities consistent with the system being coeval at 80.8±2.5 Myr, according to BHAC15 evolutionary models. The presence of lithium is consistent with model predictions, marking the first test of the theoretical lithium depletion boundary using ultracool dwarfs of known mass. However, we find that the evolutionary model-derived average effective temperature (2950±5 K) is 180 K hotter than that given by a spectral type-T eff relation based on BT-Settl models (2770±100 K). We suggest that the dominant source of this discrepancy is model radii being too small by ≈13%. In a test mimicking the typical application of models by observers, we derive masses on the H-R diagram using luminosity and BT-Settl temperature. The estimated masses are lower by -(2.0σ) than we measure dynamically and would imply that this is a system of ≈50 M Jup brown dwarfs, highlighting the large systematic errors possible in H-R diagram properties. This is the first time masses have been measured for ultracool ( M6) dwarfs displaying spectral signatures of low gravity. Based on features in the infrared, LSPMJ1314+1320AB appears to have higher gravity than typical Pleiades and ABDor members, opposite the expectation given its younger age. The components of LSPMJ1314+1320AB are now the nearest, lowest mass pre-main-sequence stars with direct mass measurements.

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Section: Evolutionary Model-derived Propertiesmentioning

confidence: 99%

High-Precision Radio and Infrared Astrometry of LSPM J1314+1320ab. Ii. Testing Pre-Main-Sequence Models at the Lithium Depletion Boundary With Dynamical Masses

Dupuy

Forbrich

Rizzuto

et al. 2016

ApJ

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“…We compared the positions of the two systems containing components of spectral type M5 or later, J061610 and GJ 852 BC, in a MK vs. T eff diagram to the Baraffe et al (2015), hereafter BHAC15, isochrones.…”

Section: Hertzsprung-russell Diagrammentioning

confidence: 99%

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Bergfors¹,

Brandner²,

Bonnefoy³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present VLT/SINFONI J, H + K spectra of seven close visual pairs in M dwarf binary/triple systems, discovered or observed by the AstraLux M dwarf survey. We determine the spectral types to within ±1.0 subclasses from comparison to template spectra and the strength of K-band water absorption, and derive effective temperatures. The results are compared to optical spectral types of the unresolved binary/multiple systems, and we confirm that our photometric method to derive spectral types in the AstraLux M dwarf survey is accurate. We look for signs of youth such as chromospheric activity and low surface gravity, and find an age in the range 0.25 − 1 Gyr for the GJ 852 system. Strong Li absorption is detected in optical spectra of the triple system J024902 obtained with FEROS at the ESO-MPG 2.2 m telescope. The equivalent width of the absorption suggests an age consistent with the β Pic moving group. However, further observations are needed to establish group membership. Ongoing orbital monitoring will provide dynamical masses and thus calibration of evolutionary models for low mass stars.

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“…We did not correct for extinction; NIR magnitudes are the least affected by optical-and NIR-excesses from accretion and inner disks. The average change in mass estimate between the Baraffe et al (1998) and Baraffe et al (2015) …”

Section: Sample Sensitivity To Companionsmentioning

confidence: 98%

“…To estimate absolute magnitudes we apply the distance to Oph of 140 pc, for Cha targets we used a distance of 160 pc (Feigelson & Lawson 2004), and for CrA and Cor targets we use a distance of 140pc (Sicilia-Aguilar et al 2008). We use the Baraffe et al (2015) 1 Myr CFHT tracks for all targets (e.g., Furlan et al 2009;Kim et al 2009). The 2MASS J magnitudes, available for all of our targets (and K where available), coupled with these age and distance estimates allowed us to estimate the mass of each target.…”

Section: Sample Sensitivity To Companionsmentioning

confidence: 99%

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Searching for Spectroscopic Binaries Within Transition Disk Objects*

Kohn

Shkolnik

Weinberger

et al. 2016

ApJ

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Transition disks (TDs) are intermediate stage circumstellar disks characterized by an inner gap within the disk structure. To test whether these gaps may have been formed by closely orbiting, previously undetected stellar companions, we collected high-resolution optical spectra of 31 TD objects to search for spectroscopic binaries (SBs). Twenty-four of these objects are in Ophiuchus and seven are within the Coronet, Corona Australis, and Chameleon I star-forming regions. We measured radial velocities for multiple epochs, obtaining a median precision of 400 ms −1 . We identified double-lined SB SSTc2d J163154.7-250324 in Ophiuchus, which we determined to be composed of a K7(±0.5) and a K9(±0.5) star, with orbital limits of a<0.6 au and P<150 days. This results in an SB fraction of -+ 0.04 0.03 0.12 in Ophiuchus, which is consistent with other spectroscopic surveys of non-TD objects in the region. This similarity suggests that TDs are not preferentially sculpted by the presence of close binaries and that planet formation around close binaries may take place over similar timescales to that around single stars.

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New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit

Cited by 1,603 publications

References 32 publications

High-Precision Radio and Infrared Astrometry of LSPM J1314+1320ab. Ii. Testing Pre-Main-Sequence Models at the Lithium Depletion Boundary With Dynamical Masses

High-Precision Radio and Infrared Astrometry of LSPM J1314+1320ab. Ii. Testing Pre-Main-Sequence Models at the Lithium Depletion Boundary With Dynamical Masses

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Searching for Spectroscopic Binaries Within Transition Disk Objects*

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