Catalogue and bibliography of the UV Cet-type flare stars
 and related objects in the solar vicinity

Гершберг, Р. Е.; Katsova, M. M.; Lovkaya, M. N.; Terebizh, A. V.; Shakhovskaya, N. I.

doi:10.1051/aas:1999407

Cited by 86 publications

(72 citation statements)

References 24 publications

(32 reference statements)

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“…Observations of flare star EV Lac by Osten et al (2005) revealed intense emission exceeding 10 13 K with a temporal structure similar to that observed for J103916.2+585124, i.e., minute-scale rise time and a decay time of hours. Furthermore, flare stars are common in the solar vicinity, with a catalog of nearby UV Cet-type flare stars by Gershberg et al (1999) indicating 463 objects within 50 pc. Outbursts exceeding 2 × 10 14 K with physical size scales equal to one solar radii should be detected in our observations for sources within 1 kpc.…”

Section: Discussionmentioning

confidence: 99%

Discovery of a Meter-Wavelength Radio Transient in the Swire Deep Field: 1046+59

Jaeger

Hyman

Kassim

et al. 2012

The Astronomical Journal

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We report the results of a low frequency radio variability and slow transient search using archival observations from the Very Long Array. We selected six 325 MHz radio observations from the spring of 2006, each centered on the Spitzer-Space-Telescope Wide-area Infrared Extragalactic Survey (SWIRE) Deep Field: 1046+59. Observations were spaced between one day to three months, with a typical single-epoch peak flux sensitivity below 0.2 mJy beam −1 near the field pointing center. We describe the observation parameters, data post-processing, and search methodology used to identify variable and transient emission. Our search revealed multiple variable sources and the presence of one, day-scale transient event with no apparent astronomical counterpart. This detection implies a transient rate of 1 ± 1 event per 6.5 deg 2 per 72 observing hours in the direction of 1046+59 and an isotropic transient surface density Σ = 0.12 deg −2 at 95% confidence for sources with average peak flux density higher than 2.1 mJy over 12 hr.

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Section: Discussionmentioning

confidence: 99%

Discovery of a Meter-Wavelength Radio Transient in the Swire Deep Field: 1046+59

Jaeger

Hyman

Kassim

et al. 2012

The Astronomical Journal

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“…The sample of stars were taken from Gershberg et al (1999) and listed in Table 1, namely the stars located in the region of α = 10 h to 13 h and δ = −24 • 30 m to −50 • . The two stars HIP 56244 and GJ 3780 do not show Lithium (see Fig 1).…”

Section: Spectroscopy In the Optical Regimementioning

confidence: 99%

“…We discuss a new member candidate of the TW Hydrae association (TWA) among the stars of the Gershberg et al (1999) flare star catalog. TWA is one of the closest known associations of young stars at about 60 pc.…”

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confidence: 99%

Flare stars in the TW Hydrae association: the HIP 57269 system

et al. 2003

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Abstract. We discuss a new member candidate of the TW Hydrae association (TWA) among the stars of the Gershberg et al. (1999) flare star catalog. TWA is one of the closest known associations of young stars at about 60 pc. Three supposedly young flare stars are located in the same region of the sky as TWA. One of them (HIP 57269) shows strong Lithium absorption with spectral type K1/K2V and a high level of chromospheric and coronal activity. It is located at a distance of 48.7 ± 6.3 pc in common with the five TWA members observed with Hipparcos (46.7 to 103.9 pc). HIP 57268 A has a wide companion C which also shows Lithium absorption at 6707Å and which has common proper motion with HIP 57269, as well as a close companion resolved visually by Tycho. HIP 57269 A&C lie above the main sequence and are clearly pre-main-sequence stars. The UVW-space velocity is more consistent with the star system being a Pleiades super cluster member. The two other flare stars in the TWA sky region do not show Lithium at all and are, hence, unrelated.

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“…Both components, A and the unresolved BC, are listed in the catalog of UV Cet-type flare stars compiled by Gershberg et al (1999). For this system, measurements of Li abundance and equivalent widths of some activity indicators are available.…”

Section: The Bd−211074 Systemmentioning

confidence: 99%

“…In contrast to the component A, we note a positive correlation between the R and the V − I color curves, which is the typical trend observed when the variability is dominated by cool spots. Both component A and BC are known to be flare stars (Gershberg et al 1999). Beside the light rotational modulation likely owing to dark spots unevenly distributed across the stellar longitudes, this implies that also transient light increases, as in flares and micro-flares, are expected to be detected.…”

Section: Photometric Rotation Periodsmentioning

confidence: 99%

Evidence from stellar rotation of enhanced disc dispersal

Messina¹,

Monard²,

Biazzo³

et al. 2014

A&A

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Context. The early stage of stellar evolution is characterized by a magnetic coupling between a star and its accretion disc, known as a star-disc locking mechanism. The disc-locking prevents the star to spin its rotation up, and its timescale depends on the disc lifetime, which should not be longer than about 10 Myr. Some mechanisms can significantly shorten this lifetime, allowing a few stars to start spinning up much earlier than other stars and increasing the observed rotation period dispersion among coeval stars. Aims. In the present study, we aim to investigate how the properties of the circumstellar environment can shorten the disc lifetime, more specifically the presence of a close stellar companion. Methods. We have identified a few multiple stellar systems, composed of stars with similar masses, which belong to associations with a known age. Since all parameters that are responsible for the rotational evolution, with the exception of environment properties and initial stellar rotation, are similar for all components, we expect that significant differences among the rotation periods can only arise from differences in the disc lifetimes. A photometric timeseries allowed us to measure the rotation periods of each component, while high-resolution spectra provided us with the fundamental parameters, v sin i and chromospheric line fluxes. Results. In the present study, we have collected timeseries photometry of BD−21 1074, a member of the 21 Myr old β Pictoris association, and measured the rotation periods of its brightest components A and B. They differ significantly, and the component B, which has a closer companion C, rotates faster than the more distant and isolated component A. It also displays a slightly higher chromospheric activity level. Conclusions. Since components A and B have similar mass, age, and initial chemical composition, we can ascribe the rotation period difference to either different initial rotation periods or different disc-locking phases arising from the presence of the close companion C. In the specific case of BD−21 1074, the second scenario seems to be more favored. However, a statistically meaningful sample is yet needed to be able to infer which scenario is more likely. In our hypothesis of different disc-locking phase, any planet orbiting this star, if found by future investigations, is likely formed very rapidly owing to a gravitational instability mechanism, rather than core accretion. Only a large difference of initial rotation periods alone could account for the observed period difference, leaving comparable disc lifetimes.

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Catalogue and bibliography of the UV Cet-type flare stars and related objects in the solar vicinity

Cited by 86 publications

References 24 publications

Discovery of a Meter-Wavelength Radio Transient in the Swire Deep Field: 1046+59

Discovery of a Meter-Wavelength Radio Transient in the Swire Deep Field: 1046+59

Flare stars in the TW Hydrae association: the HIP 57269 system

Evidence from stellar rotation of enhanced disc dispersal

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