First [ITAL]Hubble Space Telescope[/ITAL] Observations of Mira AB Wind-accreting Binary System

Karovska, M.; Hack, W.; Raymond, J. C.; Guinan, E. F.

doi:10.1086/310704

Cited by 116 publications

(171 citation statements)

References 11 publications

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“…We have found indications that a similar asymmetry is also present in the CO vibrationrotation emission intensity at a distance of approximately 3A from the star in the east direction as compared with the west direction. It is interesting to note that the companion of Mira is located eastward from the star at a position angle of (Karovska et al 1997). 108¡ .3^0¡ .1…”

Section: Discussionmentioning

confidence: 99%

Mira’s Wind Explored in Scattering Infrared CO Lines

Ryde¹,

Gustafsson²,

Eriksson³

et al. 2000

ApJ

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We have observed the intermediate regions of the circumstellar envelope of Mira (o Ceti) in photospheric light scattered by three vibration-rotation transitions of the fundamental band of CO, from lowexcited rotational levels of the ground vibrational state, at an angular distance of b D 2@@È7A away from the star. The data were obtained with the Phoenix spectrometer mounted on the 4 m Mayall telescope at Kitt Peak. The spatial resolution is approximately and seeing limited. Our observations provide 0A .5 absolute Ñuxes, leading to an independent new estimate of the mass-loss rate of approximately 3 ] 10~7 yr~1, as derived from a simple analytic wind model. We Ðnd that the scattered intensity from the M _ wind of Mira for decreases as b~3, which suggests a time constant mass-loss rate, when 2@@ [ b [ 7@@ averaged over 100 yr, over the past 1200 yr.

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Section: Discussionmentioning

confidence: 99%

Mira’s Wind Explored in Scattering Infrared CO Lines

Ryde¹,

Gustafsson²,

Eriksson³

et al. 2000

ApJ

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“…GJ86 also shows anomalies in the age indicators that are similar, even if less extreme, than those we found for HD 8049; the GJ86 age indicators yield a younger age from X-ray and H&K than from kinematic (see Desidera & Barbieri 2007, Appendix B). Another more direct indication of wind accretion onto a companion during the AGB phase is represented by the accretion disk around Mira B (Karovska et al 1997;Ireland et al 2007), which lies at a projected separation of about 70 AU, which is slightly larger than the most probable value for HD 8049.…”

Section: System Historymentioning

confidence: 99%

Astrophysical false positives in direct imaging for exoplanets: a white dwarf close to a rejuvenated star

Zurlo

Vigan

Hagelberg

et al. 2013

A&A

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Context. As is the case for all techniques involved in the research for exoplanets, direct imaging has to take into account the probability of so-called astrophysical false positives, which are phenomena that mimic the signature of the objects we are seeking. Aims. In this work we present the case of a false positive found during a direct-imaging survey conducted with VLT/NACO. A promising exoplanet candidate was detected around the K2-type star HD 8049 in July 2010. Its contrast of ∆H = 7.05 at 1.57 arcsec allowed us to assume a 35 M Jup companion at 50 projected AU, for the nominal system age and heliocentric distance. Methods. To check whether it was gravitationally bound to the host star, as opposed to an unrelated background object, we re-observed the system one year later and concluded a high probability of a bound system. We also used radial velocity measurements of the host star, spanning a time range of ∼30 yr, to constrain the companion's mass and orbital properties, as well as to probe the host star's spectral age indicators and general spectral energy distribution. We also obtained U-band imaging with EFOSC and near-infrared spectroscopy for the companion. Results. Combining all these information we conclude that the companion of HD 8049 is a white dwarf (WD) with temperature T eff = 18 800 ± 2100 K and mass M WD = 0.56 ± 0.08 M . The significant radial velocity trend combined with the imaging data indicates that the most probable orbit has a semi-major axis of about 50 AU. The discrepancy between the age indicators speaks against a bona-fide young star. The moderately high level of chromospheric activity and fast rotation, mimicking the properties of a young star, might be induced by the exchange of mass with the progenitor of the WD. This example demonstrates some of the challenges in determining accurate age estimates and identifications of faint companions.

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“…It actually belongs to a detached binary system (Mira AB) in which mass transfer by wind interaction is taking place. Sokolski & Bildsten (2010) found evidence pointing towards a white dwarf nature of Mira B, while o Ceti (Mira A) shows clear signs of stellar asymmetry (Karovska et al 1997;Reid & Menten 2007). o Ceti and its companion Mira B are separated by only ∼0.5 ′′ (Karovska et al 1997), corresponding to ∼46 AU.…”

Section: The Authorsmentioning

confidence: 99%

“…Sokolski & Bildsten (2010) found evidence pointing towards a white dwarf nature of Mira B, while o Ceti (Mira A) shows clear signs of stellar asymmetry (Karovska et al 1997;Reid & Menten 2007). o Ceti and its companion Mira B are separated by only ∼0.5 ′′ (Karovska et al 1997), corresponding to ∼46 AU. The orbital elements of the system, originally determined by Baize (1980) lead to an orbital period of P∼400 yr. A more recent revision by Prieur et al (2002) leads to an increase of the estimation of the period by nearly 100 yr (the new estimated period being P∼498 yr).…”

Section: The Authorsmentioning

confidence: 99%

Recurring OH Flares towards o Ceti: I. location and structure of the 1990s’ and 2010s’ events

Etoka

Gérard

Richards

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present the analysis of the onset of the new 2010s' OH flaring event detected in the OH ground-state main line at 1665 MHz towards o Ceti and compare its characteristics with those of the 1990s' flaring event. This is based on a series of complementary single-dish and interferometric observations both in OH and H 2 O obtained with the Nançay Radio telescope (NRT), the Medicina and Effelsberg Telescopes, the European VLBI Network (EVN), and (e)Multi-Element Radio Linked Interferometer Network ((e)MERLIN). We compare the overall characteristics of o Ceti's flaring events with those which have been observed towards other thin-shell Miras, and explore the implication of these events with respect to the standard OH circumstellar-envelope model. The role of binarity in the specific characteristics of o Ceti's flaring events is also investigated. The flaring regions are found to be less than ∼400±40 mas (i.e., ≤ 40 ± 4 AU) either side of o Ceti, with seemingly no preferential location with respect to the direction to the companion Mira B. Contrary to the usual expectation that the OH maser zone is located outside the H 2 O maser zone, the coincidence of the H 2 O and OH maser velocities suggests that both emissions arise at similar distances from the star. The OH flaring characteristics of Mira are similar to those observed in various Mira variables before, supporting the earlier results that the regions where the transient OH maser emission occurs are different from the standard OH maser zone.

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First [ITAL]Hubble Space Telescope[/ITAL] Observations of Mira AB Wind-accreting Binary System

Cited by 116 publications

References 11 publications

Mira’s Wind Explored in Scattering Infrared CO Lines

Mira’s Wind Explored in Scattering Infrared CO Lines

Astrophysical false positives in direct imaging for exoplanets: a white dwarf close to a rejuvenated star

Recurring OH Flares towards o Ceti: I. location and structure of the 1990s’ and 2010s’ events

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