scholarly journals The dynamical history of the evaporating or disrupted ice giant planet around white dwarf WD J0914+1914

2020 ◽  
Vol 492 (4) ◽  
pp. 6059-6066 ◽  
Author(s):  
Dimitri Veras ◽  
Jim Fuller

ABSTRACT Robust evidence of an ice giant planet shedding its atmosphere around the white dwarf WD J0914+1914 represents a milestone in exoplanetary science, allowing us to finally supplement our knowledge of white dwarf metal pollution, debris discs, and minor planets with the presence of a major planet. Here, we discuss the possible dynamical origins of this planet, WD J0914+1914 b. The very young cooling age of the host white dwarf (13 Myr) combined with the currently estimated planet–star separation of about 0.07 au imposes particularly intriguing and restrictive coupled constraints on its current orbit and its tidal dissipation characteristics. The planet must have been scattered from a distance of at least a few au to its current location, requiring the current or former presence of at least one more major planet in the system in the absence of a hidden binary companion. We show that WD J0914+1914 b could not have subsequently shrunk its orbit through chaotic f-mode tidal excitation (characteristic of such highly eccentric orbits) unless the planet was or is highly inflated and possibly had partially thermally self-disrupted from mode-based energy release. We also demonstrate that if the planet is currently assumed to reside on a near-circular orbit at 0.07 au, then non-chaotic equilibrium tides impose unrealistic values for the planet’s tidal quality factor. We conclude that WD J0914+1914 b either (i) actually resides interior to 0.07 au, (ii) resembles a disrupted ‘Super-Puff’ whose remains reside on a circular orbit, or (iii) resembles a larger or denser ice giant on a currently eccentric orbit. Distinguishing these three possibilities strongly motivates follow-up observations.

2020 ◽  
Vol 501 (1) ◽  
pp. 676-682
Author(s):  
F Lagos ◽  
M R Schreiber ◽  
M Zorotovic ◽  
B T Gänsicke ◽  
M P Ronco ◽  
...  

ABSTRACT The discovery of a giant planet candidate orbiting the white dwarf WD 1856+534 with an orbital period of 1.4 d poses the questions of how the planet reached its current position. We here reconstruct the evolutionary history of the system assuming common envelope evolution as the main mechanism that brought the planet to its current position. We find that common envelope evolution can explain the present configuration if it was initiated when the host star was on the asymptotic giant branch, the separation of the planet at the onset of mass transfer was in the range 1.69–2.35 au, and if in addition to the orbital energy of the surviving planet either recombination energy stored in the envelope or another source of additional energy contributed to expelling the envelope. We also discuss the evolution of the planet prior to and following common envelope evolution. Finally, we find that if the system formed through common envelope evolution, its total age is in agreement with its membership to the Galactic thin disc. We therefore conclude that common envelope evolution is at least as likely as alternative formation scenarios previously suggested such as planet–planet scattering or Kozai–Lidov oscillations.


2019 ◽  
Vol 489 (2) ◽  
pp. 2941-2953 ◽  
Author(s):  
Dimitri Veras ◽  
Jim Fuller

ABSTRACT A gas giant planet which survives the giant branch stages of evolution at a distance of many au and then is subsequently perturbed sufficiently close to a white dwarf will experience orbital shrinkage and circularization due to star–planet tides. The circularization time-scale, when combined with a known white dwarf cooling age, can place coupled constraints on the scattering epoch as well as the active tidal mechanisms. Here, we explore this coupling across the entire plausible parameter phase space by computing orbit shrinkage and potential self-disruption due to chaotic f-mode excitation and heating in planets on orbits with eccentricities near unity, followed by weakly dissipative equilibrium tides. We find that chaotic f-mode evolution activates only for orbital pericentres which are within twice the white dwarf Roche radius, and easily restructures or destroys ice giants but not gas giants. This type of internal thermal destruction provides an additional potential source of white dwarf metal pollution. Subsequent tidal evolution for the surviving planets is dominated by non-chaotic equilibrium and dynamical tides which may be well-constrained by observations of giant planets around white dwarfs at early cooling ages.


Author(s):  
Ingrid Pelisoli ◽  
R T Marsh ◽  
R P Ashley ◽  
Pasi Hakala ◽  
A Aungwerojwit ◽  
...  

Abstract Accreting magnetic white dwarfs offer an opportunity to understand the interplay between spin-up and spin-down torques in binary systems. Monitoring of the white dwarf spin may reveal whether the white dwarf spin is currently in a state of near-equilibrium, or of uni-directional evolution towards longer or shorter periods, reflecting the recent history of the system and providing constraints for evolutionary models. This makes the monitoring of the spin history of magnetic white dwarfs of high interest. In this paper we report the results of a campaign of follow-up optical photometry to detect and track the 39 sec white dwarf spin pulses recently discovered in Hubble Space Telescope data of the cataclysmic variable V1460 Her. We find the spin pulsations to be present in g-band photometry at a typical amplitude of 0.4 per cent. Under favourable observing conditions, the spin signal is detectable using 2-meter class telescopes. We measured pulse-arrival times for all our observations, which allowed us to derive a precise ephemeris for the white dwarf spin. We have also derived an orbital modulation correction that can be applied to the measurements. With our limited baseline of just over four years, we detect no evidence yet for spin-up or spin-down of the white dwarf, obtaining a lower limit of $|P/\dot{P}| > 4\times 10^{7}$ years, which is already 4 to 8 times longer than the timescales measured in two other cataclysmic variable systems containing rapidly rotating white dwarfs, AE Aqr and AR Sco.


2019 ◽  
Vol 489 (1) ◽  
pp. 168-175 ◽  
Author(s):  
Evgeni Grishin ◽  
Dimitri Veras

ABSTRACT The discovery of the intact minor planet embedded in the debris disc orbiting SDSS J1228+1040 raises questions about the dynamical history of the system. Further, the recent passage of the potentially interstellar object 1I/’Oumuamua within the Solar system has re-ignited interest in minor body flux through exoplanetary systems. Here, we utilize the new analytical formalism from Grishin et al. (2019) to estimate the rate at which the gaseous components of typical white dwarf discs trap an exo-planetesimal. We compare the types of captured orbits which arise from planetesimals originating from the interstellar medium, exo-Kuiper belts, and exo-Oort clouds. We find that the rate of interstellar medium injection is negligible, whereas capture of both exo-Kuiper and exo-Oort cloud planetesimals is viable, but strongly size-dependent. For a gaseous disc which extends much beyond its Roche limit, capture is more probable than disruption at the Roche limit. We find that the capture probability linearly increases with the radial extent of the disc. Even in systems without minor planets, capture of smaller bodies will change the disc size distribution and potentially its temporal variability. Our formalism is general enough to be applied to future discoveries of embedded planetesimals in white dwarf debris discs.


1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.


2001 ◽  
Vol 120 (5) ◽  
pp. A128-A128 ◽  
Author(s):  
H MALATY ◽  
D GRAHAM ◽  
A ELKASABANY ◽  
S REDDY ◽  
S SRINIVASAN ◽  
...  

VASA ◽  
2010 ◽  
Vol 39 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Reich-Schupke ◽  
Weyer ◽  
Altmeyer ◽  
Stücker

Background: Although foam sclerotherapy of varicose tributaries is common in daily practice, scientific evidence for the optimal sclerosant-concentration and session-frequency is still low. This study aimed to increase the knowledge on foam sclerotherapy of varicose tributaries and to evaluate the efficacy and safety of foam sclerotherapy with 0.5 % polidocanol in tributaries with 3-6 mm in diameter. Patients and methods: Analysis of 110 legs in 76 patients. Injections were given every second or third day. A maximum of 1 injection / leg and a volume of 2ml / injection were administered per session. Controls were performed approximately 6 months and 12 months after the start of therapy. Results: 110 legs (CEAP C2-C4) were followed up for a period of 14.2 ± 4.2 months. Reflux was eliminated after 3.4 ± 2.7 injections per leg. Insufficient tributaries were detected in 23.2 % after 6.2 ± 0.9 months and in 48.2 % after 14.2 ± 4.2 months, respectively. Only 30.9 % (34 / 110) of the legs required additional therapy. In 6.4 % vein surgery was performed, in 24.5 % similar sclerotherapy was repeated. Significantly fewer sclerotherapy-sessions were required compared to the initial treatment (mean: 2.3 ± 1.4, p = 0.0054). During the whole study period thrombophlebitis (8.2 %), hyperpigmentation (14.5 %), induration in the treated region (9.1 %), pain in the treated leg (7.3 %) and migraine (0.9 %) occurred. One patient with a history of thrombosis developed thrombosis of a muscle vein (0.9 %). After one year there were just hyperpigmentation (8.2 %) and induration (1.8 %) left. No severe adverse effect occurred. Conclusions: Foam sclerotherapy with injections of 0.5 % polidocanol every 2nd or 3rd day, is a safe procedure for varicose tributaries. The evaluation of efficacy is difficult, as it can hardly be said whether the detected tributaries in the controls are recurrent veins or have recently developed in the follow-up period. The low number of retreated legs indicates a high efficacy and satisfaction of the patients.


Author(s):  
Adam Lee ◽  
Adam Bajinting ◽  
Abby Lunneen ◽  
Colleen M. Fitzpatrick ◽  
Gustavo A. Villalona

AbstractReports of incidental pneumomediastinum in infants secondary to inflicted trauma are limited. A retrospective review of infants with pneumomediastinum and history of inflicted trauma was performed. A comprehensive literature review was performed. Three infants presented with pneumomediastinum associated with inflicted trauma. Mean age was 4.6 weeks. All patients underwent diagnostic studies, as well as a standardized evaluation for nonaccidental trauma. All patients with pneumomediastinum were resolved at follow-up. Review of the literature identified other cases with similar presentations with related oropharyngeal injuries. Spontaneous pneumomediastinum in previously healthy infants may be associated with inflicted injuries. Clinicians should be aware of the possibility of an oropharyngeal perforation related to this presentation.


1970 ◽  
Vol 24 (2) ◽  
pp. 75-78
Author(s):  
MA Hayee ◽  
QD Mohammad ◽  
H Rahman ◽  
M Hakim ◽  
SM Kibria

A 42-year-old female presented in Neurology Department of Sir Salimullah Medical College with gradually worsening difficulty in talking and eating for the last four months. Examination revealed dystonic tongue, macerated lips due to continuous drooling of saliva and aspirated lungs. She had no history of taking antiparkinsonian, neuroleptics or any other drugs causing dystonia. Chest X-ray revealed aspiration pneumonia corrected later by antibiotics. She was treated with botulinum toxin type-A. Twenty units of toxin was injected in six sites of the tongue. The dystonic tongue became normal by 24 hours. Subsequent 16 weeks follow up showed very good result and the patient now can talk and eat normally. (J Bangladesh Coll Phys Surg 2006; 24: 75-78)


2019 ◽  
Author(s):  
Ayesha Shaikh ◽  
Natasha Shrikrishnapalasuriyar ◽  
Giselle Sharaf ◽  
David Price ◽  
Maneesh Udiawar ◽  
...  

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