scholarly journals Unseen companions of V Hya inferred from periodic ejections

2019 ◽  
Vol 487 (3) ◽  
pp. 3029-3036 ◽  
Author(s):  
Jesus M Salas ◽  
Smadar Naoz ◽  
Mark R Morris ◽  
Alexander P Stephan
Keyword(s):  
Orbital Period ◽  
Triple System ◽  
High Speed ◽  
Hubble Space Telescope ◽  
Eccentric Orbit ◽  
Brown Dwarf ◽  
High Eccentricity ◽  
Distant Object ◽  
Space Telescope ◽  
Ejection Mechanism

ABSTRACT A recent study using Hubble Space Telescope observations found periodic, high-speed, collimated ejections (or ‘bullets’) from the star V Hya. The authors of that study proposed a model associating these bullets with the periastron passage of an unseen, substellar companion in an eccentric orbit and with an orbital period of ∼8 yr. Here we propose that V Hya is part of a triple system, with a substellar companion having an orbital period of ∼8 yr, and a tertiary object on a much wider orbit. In this model, the more distant object causes high-eccentricity excitations on the substellar companion’s orbit via the Eccentric Kozai–Lidov mechanism. These eccentricities can reach such high values that they lead to Roche-lobe crossing, producing the observed bullet ejections via a strongly enhanced accretion episode. For example, we find that a ballistic bullet ejection mechanism can be produced by a brown-dwarf-mass companion, while magnetically driven outflows are consistent with a Jovian-mass companion. Finally, we suggest that the distant companion may reside at few a hundred astronomical units on an eccentric orbit.

scholarly journals Hubble Space Telescope Far-UV Spectroscopy of the Short Orbital Period Recurrent Nova CI Aql: Implications for White Dwarf Mass Evolution

2019 ◽  
Vol 872 (1) ◽  
pp. 68
Author(s):  
Edward M. Sion ◽  
R. E. Wilson ◽  
Patrick Godon ◽  
Sumner Starrfield ◽  
Robert E. Williams ◽  
...  
Keyword(s):  
Orbital Period ◽  
White Dwarf ◽  
Hubble Space Telescope ◽  
Uv Spectroscopy ◽  
Space Telescope ◽  
Recurrent Nova

scholarly journals Surveying the Solar Neighborhood for Brown Dwarf Companions with the ECLIPSE Discovery Mission

2003 ◽  
Vol 211 ◽  
pp. 523-524
Author(s):  
Karl Stapelfeldt
Keyword(s):  
Luminosity Function ◽  
Hubble Space Telescope ◽  
Scattered Light ◽  
Solar Neighborhood ◽  
Brown Dwarf ◽  
Space Telescope ◽  
Effective Temperatures

The proposed Eclipse Discovery mission is an optical space telescope designed to provide a thousandfold reduction in scattered light near bright stars in comparison to any Hubble Space Telescope instrument. A survey of 500 single stars within 15 pc can detect companions with absolute z magnitude of 22 at separations > 10 AU in most of the targets. Spectrophotometry of CH4 and H2O bands between 0.8-1.0 μm can be used to derive the effective temperatures of the objects. The ECLIPSE brown dwarf survey would directly measure the luminosity function of brown dwarf companions down to ~20 Jupiter masses, providing a crucial comparison with field objects.

scholarly journals High Speed UV Photometry of the AM Her Systems AM Her, VV Pup And V834 Cen, with the Hubble Space Telescope

1996 ◽  
Vol 158 ◽  
pp. 223-224
Author(s):  
K. Schaefer ◽  
H. Bond ◽  
G. Chanmugam
Keyword(s):  
Preliminary Analysis ◽  
High Speed ◽  
Hubble Space Telescope ◽  
Cataclysmic Variables ◽  
Low Frequency ◽  
Gabor Transform ◽  
Periodic Oscillations ◽  
Space Telescope ◽  
Uv Photometry ◽  
Magnetic Cataclysmic Variables

We have used the High Speed Photometer (HSP) aboard the Hubble Space Telescope to observe the magnetic cataclysmic variables VV Pup, AM Her, and V834 Cen in the UV (1400…3300 Å) with 0.01 s time resolution. We detected low frequency flickering in all three systems, and compare the time-scales with the predictions of King (1989). At higher frequencies we searched for shock oscillations from the accretion column(s) in these systems. The data were analyzed using the Gabor transform wavelet-like technique (Heil & Walnut 1989) to search for frequency evolution throughout each observation. Preliminary analysis suggests the detection of rapid UV quasi-periodic oscillations (QPOs) in VV Pup at 0.74 Hz, and at 4.4 Hz in V834 Cen. As in ground based observations, our observations failed to yield any rapid QPOs in AM Her itself.

scholarly journals VERTICAL ATMOSPHERIC STRUCTURE IN A VARIABLE BROWN DWARF: PRESSURE-DEPENDENT PHASE SHIFTS IN SIMULTANEOUS HUBBLE SPACE TELESCOPE - SPITZER LIGHT CURVES

2012 ◽  
Vol 760 (2) ◽  
pp. L31 ◽  
Author(s):  
Esther Buenzli ◽  
Dániel Apai ◽  
Caroline V. Morley ◽  
Davin Flateau ◽  
Adam P. Showman ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Phase Shifts ◽  
Light Curves ◽  
Brown Dwarf ◽  
Space Telescope ◽  
Atmospheric Structure

scholarly journals The Y dwarf population with HST: unlocking the secrets of our coolest neighbours – I. Overview and first astrometric results

2020 ◽  
Vol 501 (1) ◽  
pp. 911-915
Author(s):  
C Fontanive ◽  
L R Bedin ◽  
D C Bardalez Gagliuffi
Keyword(s):  
Proper Motion ◽  
Hubble Space Telescope ◽  
Proper Motions ◽  
Brown Dwarf ◽  
Space Telescope ◽  
First Results

ABSTRACT In this paper, we present our project that aims at determining accurate distances and proper motions for the Y brown dwarf population using the Hubble Space Telescope. We validate the program with our first results, using a single new epoch of observations of the Y0pec dwarf WISE J163940.83−684738.6. These new data allowed us to refine its proper motion and improve the accuracy of its parallax by a factor of three compared to previous determinations, now constrained to ϖ = 211.11 ± 0.56 mas. This newly derived absolute parallax corresponds to a distance of 4.737 ± 0.013 pc, an exquisite and unprecedented precision for faint ultracool Y dwarfs.

High-Speed Hubble Space Telescope Ultraviolet photometry of two DB white dwarfs: Nonradial and radial pulsations

1994 ◽  
Vol 107 ◽  
pp. 298 ◽  
Author(s):  
Steven D. Kawaler ◽  
Howard E. Bond ◽  
Lisa E. Sherbert ◽  
Todd K. Watson
Keyword(s):  
High Speed ◽  
White Dwarfs ◽  
Hubble Space Telescope ◽  
Space Telescope ◽  
Radial Pulsations

scholarly journals The Polarization of the Crab Pulsar with HST

1996 ◽  
Vol 160 ◽  
pp. 301-302
Author(s):  
Joseph F. Dolan ◽  
Patricia T. Boyd ◽  
Robert J. Hill ◽  
F. Graham-Smith ◽  
A. G. Lyne ◽  
...  
Keyword(s):  
Time Resolution ◽  
Linear Polarization ◽  
High Speed ◽  
Hubble Space Telescope ◽  
Position Angle ◽  
Crab Pulsar ◽  
Pulse Profile ◽  
Space Telescope ◽  
Pulse Phase ◽  
Sample Time

The linear polarization of the Crab pulsar as a function of pulse phase was observed by the High Speed Photometer on the Hubble Space Telescope in March, 1993. Observations were obtained in a bandpass centered on 2770 A using a 0.25 ms sample time, corresponding to a time resolution of 0.0075 in pulse phase. The UV polarization of the pulsar [Fig. 1] is strikingly similar to that observed in the visible (cf. Smith et al. 1988). The same values of polarization and the same swing of position angle occur through the main and secondary pulses. The polarization pulse profile must be essentially wavelength independent at frequencies above the infrared.

scholarly journals Hubble Space Telescope NICMOS Observations of T Dwarfs: Brown Dwarf Multiplicity and New Probes of the L/T Transition

2006 ◽  
Vol 166 (2) ◽  
pp. 585-612 ◽  
Author(s):  
Adam J. Burgasser ◽  
J. Davy Kirkpatrick ◽  
Kelle L. Cruz ◽  
I. Neill Reid ◽  
Sandy K. Leggett ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Brown Dwarf ◽  
Space Telescope

scholarly journals Hubble Space Telescope astrometry of the closest brown dwarf binary system – I. Overview and improved orbit★

2017 ◽  
Vol 470 (1) ◽  
pp. 1140-1155 ◽  
Author(s):  
L. R. Bedin ◽  
D. Pourbaix ◽  
D. Apai ◽  
A. J. Burgasser ◽  
E. Buenzli ◽  
...  
Keyword(s):  
Binary System ◽  
Hubble Space Telescope ◽  
Brown Dwarf ◽  
Space Telescope
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