Spectroscopic Pre–Main-Sequence Binaries. II. Haro 1-14[CLC]c[/CLC] and Parenago 2494

Reipurth, Bo; Lindgren, H.; Mayor, M.; Mermilliod, J. C.; Cramer, N.

doi:10.1086/344108

Cited by 22 publications

(28 citation statements)

References 34 publications

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“…Another short-period binary system (RX J1108.8-7519) was found by Covino et al (1997). The long-period binaries are NTTS162819-2423S (period 89.1 days, ρ Oph), Wa Oph 1 (=NTTS160814-1857, period 144.7 days, SC), and Haro 1-14c (period 591 days, ρ Oph) (see also Reipurth et al 2002). NTTS162819-2423S and Haro 1-14c are both members of hierarchical systems.…”

Section: Discussionmentioning

confidence: 93%

Pre-main sequence spectroscopic binaries suitable for VLTI observations

Guenther

Esposito

Mundt

et al. 2007

A&A

114

115

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Context.A severe problem for research in star-formation is that the masses of young stars are almost always estimated from evolutionary tracks alone. Since the tracks published by different groups differ, it is often only possible to give a rough estimate of the masses of young stars. It is thus crucial to test and calibrate the tracks. Up to now, only a few tests of the tracks could be carried out. However, it is now possible with the VLTI to set constrains on the tracks by determining the masses of many young binary stars precisely. Aims. In order to use the VLTI efficiently, a first step is to find suitable targets, which is the purpose of this work. Given the distance of nearby star-forming regions, suitable VLTI targets are binaries with orbital periods between at least 50 days and a few years. Although a number of surveys for detecting spectroscopic binaries have been carried out, most of the binaries found so far have periods that are too short. Methods. We thus surveyed the Chamaeleon, Corona Australis, Lupus, Sco-Cen, and ρ Ophiuci star-forming regions in order to search for spectroscopic binaries with periods longer than 50 days, which are suitable for the VLTI observations. Results. As a result of the 8 year campaign, we discovered 8 binaries with orbital periods longer than 50 days. Amongst the newly discovered long-period binaries is CS Cha, which is one of the few classical T Tauri stars with a circumbinary disk. The survey is limited to objects with masses higher than 0.1 to 0.2 M for periods between 1 and 8 years. Conclusions. We find that the frequency of binaries with orbital periods ≤3000 days is of 20 ± 5%. The frequency of long and short period pre-main sequence spectroscopic binaries is about the same as for stars in the solar neighbourhood. In total 14 young binaries are now known that are suitable for mass determination with the VLTI.

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Section: Discussionmentioning

confidence: 93%

Pre-main sequence spectroscopic binaries suitable for VLTI observations

Guenther

Esposito

Mundt

et al. 2007

A&A

114

115

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“…According to Brandner (1992) and Reipurth & Zinnecker (1993), there is a second wide visual companion candidate at 11.4 arcsec separation outside the FoV of our NACO S13 observations. Reipurth et al (2002) report from their spectroscopy data, with the primary and secondary situated in the spectrograph entrance window, that the object is a spectroscopic binary candidate with a possible period of about 125 days. While the spectro-astrometric displacement found by Takami et al (2003) is small and might be caused by the binarity also recovered by us at ∼2 arcsec, Covino et al (1997), Melo (2003), Guenther et al (2007) and Joergens (2008) all found no evidence of a spectroscopic binarity.…”

Section: Sz 41mentioning

confidence: 99%

“…(23) **, w*: Brandner (1992); Reipurth & Zinnecker (1993), SB? (primary and secondary in spectrograph entrance window): Reipurth et al (2002). (24) Hyland et al (1982).…”

Section: Introductionmentioning

confidence: 99%

Astrometric confirmation of young low-mass binaries and multiple systems in the Chamaeleon star-forming regions

Vogt

Schmidt

Neuhäuser

et al. 2012

A&A

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Context. The star-forming regions in Chamaeleon (Cha) are one of the nearest (distance ∼ 165 pc) and youngest (age ∼ 2 Myr) conglomerates of recently formed stars and the ideal target for population studies of star formation. Aims. We investigate a total of 16 Cha targets that have been suggested, but not confirmed, to be binaries or multiple systems in previous literature. Methods. We used the adaptive optics instrument Naos-Conica (NACO) at the Very Large Telescope Unit Telescope (UT) 4 / YEPUN of the Paranal Observatory, at 2-5 different epochs, in order to obtain relative and absolute astrometric measurements, as well as differential photometry in the J, H, and K band. On the basis of known proper motions and these observations, we analyse the astrometric results in our proper motion diagram (PMD: angular separation / position angle versus time), to eliminate possible (non-moving) background stars, establish co-moving binaries and multiples, and search for curvature as indications for orbital motion. Results. All previously suggested close components are co-moving and no background stars are found. The angular separations range between 0.07 and 9 arcsec, corresponding to projected distances between the components of 6-845 AU. Thirteen stars are at least binaries and the remaining three (RX J0919.4-7738, RX J0952.7-7933, VW Cha) are confirmed high-order multiple systems with up to four components. In 13 cases, we found significant slopes in the PMDs, which are compatible with orbital motion whose periods (estimated from the observed gradients in the position angles) range from 60 to 550 years. However, in only four cases there are indications of a curved orbit, the ultimate proof of a gravitational bond. Conclusions. A statistical study based on the 2MASS catalogue confirms the high probability of all 16 stellar systems being gravitationally bound. Most of the secondary components are well above the mass limit of hydrogen burning stars (0.08 M ), and have masses twice as high as this value or more. Massive primary components appear to avoid the simultaneous formation of equal-mass secondary components, while extremely low-mass secondary components are hard to find for both high and low mass primaries owing to the much higher dynamic range and the faintness of the secondaries.

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“…Reipurth et al (2002) found that the star shows periodic variability in the V band with an amplitude of 0.10 mag and a period of 5.77 days (cf. the orbital period of 19.48 days).…”

Section: Other Sourcesmentioning

confidence: 99%

Hunting for millimeter flares from magnetic reconnection in pre-main sequence spectroscopic binaries

Kóspál

Salter

Hogerheijde

et al. 2011

A&A

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Context. Recent observations of the low-mass pre-main sequence (PMS), eccentric spectroscopic binaries DQ Tau and V773 Tau A reveal that their millimeter spectrum is occasionally dominated by flares from non-thermal emission processes. The transient activity is believed to be synchrotron in nature, resulting from powerful magnetic reconnection events when the separate magnetic structures of the binary components are briefly capable of interacting and forced to reorganize, typically near periastron. Aims. We conducted the first systematic study of the millimeter variability toward a sample of 12 PMS spectroscopic binaries with the aim to characterize the proliferation of flares amongst sources likely to experience similar interbinary reconnection events. The source sample consists entirely of short-period, close-separation binaries that possess either a high orbital eccentricity (e > 0.1) or a circular orbit (e ≈ 0). Methods. Using the MAMBO2 array on the IRAM 30 m telescope, we carried out continuous monitoring at 1.25 mm (240 GHz) over a 4-night period during which all of the high-eccentricity binaries approached periastron. We also obtained simultaneous optical VRI measurements, since a strong link is often observed between stellar reconnection events (traced via X-rays) and optical brightenings. Results. UZ Tau E is the only source to be detected at millimeter wavelengths, and it exhibited significant variation (F 1.25mm = 87-179 mJy); it is also the only source to undergo strong simultaneous optical variability (ΔR ≈ 0.9 mag). The binary possesses the largest orbital eccentricity in the current sample, a predicted factor in star-star magnetic interaction events. With orbital parameters and variable accretion activity similar to DQ Tau, the millimeter behavior of UZ Tau E draws many parallels to the DQ Tau model for colliding magnetospheres. However, on the basis of our observations alone, we cannot determine whether the variability is repetitive, or if it could also be due to variable free-free emission in an ionized wind. Conclusions. UZ Tau E brings the number of known millimeter-varying PMS sources to 3 out of a total of 14 monitored binaries now in the literature. Important factors in the non-detection of the rest of our targets are the coarse time-sampling and limited millimeter sensitivity of our survey. We recommend that future studies concentrate on close-by targets, and obtain millimeter and optical data points with better temporal resolution.

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Spectroscopic Pre–Main-Sequence Binaries. II. Haro 1-14[CLC]c[/CLC] and Parenago 2494

Cited by 22 publications

References 34 publications

Pre-main sequence spectroscopic binaries suitable for VLTI observations

Pre-main sequence spectroscopic binaries suitable for VLTI observations

Astrometric confirmation of young low-mass binaries and multiple systems in the Chamaeleon star-forming regions

Hunting for millimeter flares from magnetic reconnection in pre-main sequence spectroscopic binaries

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