BD + 22 4409: a rapidly rotating, low-mass member of the local Association

Jeffries, R. D.; Byrne, P. B.; Doyle, J. G.; Anders, G. J.; James, D. J.; Lanzafame, A. C.

doi:10.1093/mnras/270.1.153

Cited by 39 publications

(57 citation statements)

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“…(1) Montes et al (2001); (2) Zuckerman & Song (2004); (3) Guirado et al (2006); (4) Lim & White (1995); (5) Lim (1993); (6) Janson et al (2006); (7) Azulay et al (2012); (8) Güdel et al (1995); (9) Konig et al (2005); (10) Hormuth et al (2007); (11) Evans et al (2012); (12) this paper; (13) Jeffries et al (1994); (14) Wichmann et al (2003); (15) VLA data archive. …”

Section: Discussionmentioning

confidence: 87%

Radio detection of the young binary HD 160934

Azulay

Guirado

Marcaide

et al. 2013

A&A

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Context. Precise determination of dynamical masses of pre-main-sequence (PMS) stars is essential to calibrate stellar evolution models that are widely used to derive theoretical masses of young low-mass objects. Binary stars in young, nearby loose associations are particularly good candidates for this calibration since all members share a common age. Interestingly, some of these young binaries present a persistent and compact radio emission, which makes them excellent targets for astrometric VLBI studies. Aims. We aim to monitor the orbital motion of the binary system HD 160934, a member of the AB Doradus moving group. Methods. We observed HD 160934 with the Very Large Array and the European VLBI Network at 8.4 and 5 GHz, respectively. The orbital information derived from these observations was analyzed along with previously reported orbital measurements. Results. We show that the two components of the binary, HD 160934 A and HD 160934 c, display compact radio emission at VLBI scales, providing precise information on the relative orbit. Revised orbital elements were estimated. Conclusions. Future VLBI monitoring of this pair should determine precise model-independent mass estimates for the A and c components, which will serve as calibration tests for PMS evolutionary models.

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Section: Discussionmentioning

confidence: 87%

Radio detection of the young binary HD 160934

Azulay

Guirado

Marcaide

et al. 2013

A&A

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“…Several studies of the relation of Li abundance with stellar activity were published. These studies had different results though, from a clear correlation (e.g., Jeffries et al 1994;Fernández & Miranda 1998;Neuhäuser et al 1998) to no relation at all, even in the presence of very strong starspot activity (e.g., Pallavacini et al 1993;Mallik 1998;.…”

Section: Introductionmentioning

confidence: 99%

Doppler imaging of stellar surface structure

Kővári¹,

Korhonen²,

Strassmeier³

et al. 2013

A&A

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Aims. We present the first Doppler imaging study of the two rapidly rotating, single K-giants DP CVn and DI Psc in order to study the surface spot configuration and to pinpoint their stellar evolutionary status. Methods. Optical spectroscopy and photometry were used to determine the fundamental astrophysical properties. Doppler imaging was applied to recover the surface temperature distribution for both stars, while photometric light-curve inversions were carried out for studying the long-term changes of the surface activity of DP CVn. Surface differential rotation of DP CVn was estimated from cross-correlating the available subsequent Doppler reconstructions separated by roughly one rotation period. Results. Both stars appear to have higher than normal lithium abundance, LTE log n of 2.28 (DP CVn) and 2.20 (DI Psc), and are supposed to be located at the end of the first Li dredge-up on the RGB. Photometric observations reveal rotational modulation with a period of 14.010 d (DP CVn) and 18.066 d (DI Psc). Doppler reconstructions from the available mapping lines well agree in the revealed spot patterns, recovering rather low latitude spots for both stars with temperature contrasts of ΔT ≈ 600−800 K below the unspotted photospheric background. Spots at higher latitudes are also found but either with less contrast (DP CVn) or with smaller extent (DI Psc). A preliminary antisolar-type differential rotation with α = −0.035 is found for DP CVn from cross-correlating the subsequent Doppler images. Long-term photometric analysis supports the existence of active longitudes, as well as the differential rotation.

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“…It is a young, K5V-K8V type and member of AB Doradus moving group (Zuckerman et al 2004). Presence of strong flaring activity was identified by Jeffries et al(1994) and Eibe et al (1999) from H α and He I D3 observations. Pandey et al (2009) showed strong modulation in broad band linear polarization and suggested that it could be the result of scattering of an anisotropic stellar radiation field by an optically thin circumstellar envelope or scattering of the stellar radiation by prominence-like structures.…”

Section: Introductionmentioning

confidence: 79%

Long-term spot topography and multi-band flare analysis of active ultra-fast rotator LO Peg

Pandey¹,

Karmakar²,

Саванов³

2015

Proceedings of Swift: 10 Years of Discovery — PoS(SWIFT 10)

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We present analyses of optical photometric and X-ray observations of the star LO Peg. Nearly 26 yrs of optical observations show that LO Peg is a periodic variable with a photometric period of 0.422853 ± 0.000005 d. Light curves observed at 47 epochs in V-band show changes in minima, amplitude and shape indicating that the variability is due to the presence of surface inhomogeneities. The surface coverage of spots was found to be in the range of 9-26 %. Most of the time, the spots were resolved as two active longitudes. The corona of LO Peg consists of a two temperature plasma of 3.24×10 6 K and 11.95×10 6 K. The average X-ray luminosity in the 0.3-10.0 keV energy band was found 3.56 × 10 29 erg s −1 . Flaring features in optical V-band with flare energies of the order of 10 33 erg were also noticed.

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BD + 22 4409: a rapidly rotating, low-mass member of the local Association

Cited by 39 publications

References 0 publications

Radio detection of the young binary HD 160934

Radio detection of the young binary HD 160934

Doppler imaging of stellar surface structure

Long-term spot topography and multi-band flare analysis of active ultra-fast rotator LO Peg

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