The Changing Rotational Light-curve Amplitude of Varuna and Evidence for a Close-in Satellite

Fernández-Valenzuela, E.; Ortiz, J. L.; Morales, N.; Santos-Sanz, P.; Duffárd, R.; Aznar, Amadeo; Lorenzi, V.; Pinilla-Alonso, N.; Lellouch, E.

doi:10.3847/2041-8213/ab40c2

Cited by 10 publications

(12 citation statements)

References 23 publications

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“…First, the inversion technique requires the viewing of a body from multiple aspect angles. Because KBOs are distant and move slowly, so far only a few objects, (139775) 2001 QG298 (Lacerda, 2011) and ( 20000) Varuna (Fernández-Valenzuela et al, 2019), have long enough measurement baselines to begin this sort of analysis. Second, due to their small size and great distance, few KBOs have been sampled with sufficient regularity and signal-to-noise (SNR) for inversion techniques to be applicable.…”

Section: Introductionmentioning

confidence: 99%

A statistical review of light curves and the prevalence of contact binaries in the Kuiper Belt

Showalter

Benecchi

Grundy

et al. 2021

Icarus

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Section: Introductionmentioning

confidence: 99%

A statistical review of light curves and the prevalence of contact binaries in the Kuiper Belt

Showalter

Benecchi

Grundy

et al. 2021

Icarus

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“…According to the different expressions for the tidal locking timescales applied to TNOs with satellites in Thirouin et al (2014) and Fernández-Valenzuela et al (2019), the putative satellite would have synchronized its orbit and spin in times of the order of one to one hundred million years, assuming typical values for the tidal dissipation parameter Q and for the rigidity of ice, and assuming a satellite radius of 100km and a density of 600 kg/m 3 . This timescale is orders of magnitude lower than the age of the solar system.…”

Section: Discussionmentioning

confidence: 99%

“…The observations were performed in the same way and with the same instruments as described in section 2. The methods and tools used to extract the photometry were the same as those explained in Fernández-Valenzuela et al (2019). A total of 875 measurements were obtained, which can be found as on-line material.…”

Section: Light Curves Of 2002 Tc 302 To Determine the Rotational Periodmentioning

confidence: 99%

The large Trans-Neptunian Object 2002 TC$_{302}$ from combined stellar occultation, photometry and astrometry data

Ortiz,

Santos-Sanz,

Sicardy

et al. 2020

Preprint

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Context. Deriving physical properties of Trans-Neptunian Objects is important for the understanding of our solar system. This requires observational efforts and the development of techniques suitable for these studies. Aims. Our aim was to characterize the large Trans-Neptunian Object 2002 TC 302 Methods. Stellar occultations offer unique opportunities to determining key physical properties of Trans-Neptunian Objects. On 28 th January 2018, the large Trans-Neptunian Object 2002 TC 302 occulted a m v ∼ 15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a Trans-Neptunian Object other than Pluto, in terms of the number of chords published thus far. From the twelve chords, an accurate elliptical fit to the instantaneous projection of the body, compatible with the near misses, can be obtained.Results. The resulting ellipse has major and minor axes of 543 ± 18 km and 460 ± 11 km, respectively, with a position angle of 3 ± 1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5-m telescope at Sierra Nevada Observatory and the 1.23-m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body, based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84 km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ∼ 300 km in diameter, to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also appears to be consistent with other ground-based data presented here. From the effective occultation diameter combined with absolute magnitude measurements we derive a geometric albedo of 0.147 ± 0.005, which would be somewhat smaller if 2002 TC 302 has a satellite. The best occultation light curves do not show any signs of ring features or any signatures of a global atmosphere.

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“…Varuna is a classical Kuiper belt object. In 2019, it was proposed that changes in the rotational lightcurve shape of Varuna may be caused by the presence of a large undiscovered satellite [9]. Multi-band thermal observations from the Herschel Space Observatory in 2013 proposed the mean diameter of Varuna equal to 668 km [15].…”

Section: Target Descriptionmentioning

confidence: 99%

Astrometric and photometric observations of six brightest trans-Neptunian objects at the Kyiv comet station

Baransky

Lukina

Borysenko

2020

Adv.Astron.Spa.Physics

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In this work we focused on observations of six trans-Neptunian objects (TNOs) whose apparent magnitudes are brighter than 20m. We present the results of astrometric and photometric observations of (134340) Pluto, (136108) Haumea, (136472) Makemake, (136199) Eris, (90482) Orcus, and (20000) Varuna obtained at the Kyiv comet station (Code MPC 585) in 2017-2019. For observations we used the 0.7-m (f/4) reflector AZT-8 with FLI PL4710 CCD camera and filters of Johnson-Cousins photometric system. From our images we measured the objects' astrometric positions, calculated apparent magnitudes in the BVRI (mostly R) bands using aperture photometry method, and found absolute magnitudes together with the colour indices in several bands. Analysing our results, we investigate the limitation on the astrometry and photometry of faint objects with the 0.7-m telescope.

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The Changing Rotational Light-curve Amplitude of Varuna and Evidence for a Close-in Satellite

Cited by 10 publications

References 23 publications

A statistical review of light curves and the prevalence of contact binaries in the Kuiper Belt

A statistical review of light curves and the prevalence of contact binaries in the Kuiper Belt

The large Trans-Neptunian Object 2002 TC$_{302}$ from combined stellar occultation, photometry and astrometry data

Astrometric and photometric observations of six brightest trans-Neptunian objects at the Kyiv comet station

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