Generalized Derivation of the RRV Method and Its Application

Lin, F. R.; Peng, Qiwei; Wang, N.; Peng, Huan-Wen; Zhang, Qingfeng; Li, Z.

doi:10.3847/0004-6256/152/6/183

Cited by 5 publications

(9 citation statements)

References 11 publications

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“…We present them in Tables 2 and 3. We explored using the rotational reflex velocity (RRV) method to determine these asteroids distances Lin et al 2016); however, be- cause our observations were not taken near opposition, this method does not provide a one-to-one mapping to distance.…”

Section: Detectionsmentioning

confidence: 99%

A New Blind Asteroid Detection Scheme

Golovich¹,

Lifset²,

Armstrong³

et al. 2021

Preprint

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As astronomical photometric surveys continue to tile the sky repeatedly, the potential to push detection thresholds to fainter limits increases; however, traditional digital-tracking methods cannot achieve this efficiently beyond time scales where motion is approximately linear. In this paper we prototype an optimal detection scheme that samples under a user defined prior on a parameterization of the motion space, maps these sampled trajectories to the data space, and computes an optimal signal-matched filter for computing the signal to noise ratio of trial trajectories. We demonstrate the capability of this method on a small test data set from the Dark Energy Camera. We recover the majority of asteroids expected to appear and also discover hundreds of new asteroids with only a few hours of observations. We conclude by exploring the potential for extending this scheme to larger data sets that cover larger areas of the sky over longer time baselines.

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Section: Detectionsmentioning

confidence: 99%

A New Blind Asteroid Detection Scheme

Golovich¹,

Lifset²,

Armstrong³

et al. 2021

Preprint

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“…The first two nights (March 30-31) constituted a 'discovery run' in which thousands of new asteroids would be found and measured over two nights. Measurements on two consecutive nights confirm the reality of faint objects and enable the calculation of accurate distances using the RRV method (Heinze & Metchev 2015a;Lin et al 2016). We intended the second pair of nights (April 07-08) as a 'recovery run' in which most of the asteroids would be recovered and approximate orbits could be calculated from the resulting 8-9 day arcs.…”

Section: Choice Of Target Fieldsmentioning

confidence: 99%

“…Our sensitivity on April 07 and 08 is at least one magnitude worse than during our discovery run, and approximate orbits will be calculable only for a minority of the new asteroids found in our discovery run. Fortunately, we can use the rotational reflex velocity (RRV) method (Heinze & Metchev 2015a;Lin et al 2016) to calculate the distances and absolute magnitudes of all the newly discovered asteroids using only the data from March 30 and 31, when the seeing was 1-1.5 arcsec (Figure 2). Our 50% completeness limit on these nights was fainter than 25th magnitude, representing a regime of flux and absolute magnitude that has never before been systematically analyzed in the main belt.…”

Section: Observing Conditions and Acquired Datamentioning

confidence: 99%

“…However, a simpleminded extrapolation will produce predictions offset to the west of the asteroids' actual locations if looking forward in time (i.e., from March 30 detections to predictions for March 31), and offset to the east if we look back in time. The reason for this systematic error is the rotational reflex velocity (RRV; see Heinze & Metchev 2015a;Lin et al 2016): that is, the part of the asteroid's angular velocity that is due neither to the orbital velocity of the asteroid nor that of the Earth, but rather to the observer's rotation about the geocenter. This rotational velocity averages to zero over a full day, but throughout the nightime hours it maintains a positive component in the same direction as the Earth's orbit.…”

Section: Survey Completeness From Fake Asteroidsmentioning

confidence: 99%

“…Since we observed the same field on two consecutive nights, we are able to confirm the reality of most of our asteroids by detecting the same objects in two independent data sets. Two-night detection will also enable us to obtain distances with ∼ 1.5% accuracy (and hence absolute magnitudes) using the RRV method of Heinze & Metchev (2015a) and Lin et al (2016). We reserve our analysis of the distance determinations and the absolute magnitude and size distributions for a companion paper (Heinze et al, in prep.…”

Section: Introductionmentioning

confidence: 99%

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The Flux Distribution and Sky Density of 25th Magnitude Main Belt Asteroids

Heinze,

Trollo,

Metchev

2019

Preprint

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Digital tracking enables telescopes to detect asteroids several times fainter than conventional techniques. We describe our optimized methodology to acquire, process, and interpret digital tracking observations, and we apply it to probe the apparent magnitude distribution of main belt asteroids fainter than any previously detected from the ground. All-night integrations with the Dark Energy Camera (DECam) yield 95% completeness at R magnitude 25.0, and useful sensitivity to R = 25.6 mag when we use an analytical detection model to correct flux overestimation bias. In a single DECam field observed over two nights, we detect a total of 3234 distinct asteroids, of which 3123 are confirmed on both nights. At opposition from the Sun, we find a sky density of 697 ± 15 asteroids per square degree brighter than R = 25.0 mag, and 1031 ± 23 brighter than R = 25.6 mag. We agree with published results for the sky density and apparent magnitude distribution of asteroids brighter than R = 23 mag. For a power law defined by dN/dR ∝ 10 αR , we find marginally acceptable fits with a constant slope α = 0.28 ± 0.02 from R = 20 to 25.6 mag. Better fits are obtained for a broken power law with α = 0.218 ± 0.026 for R = 20 to 23.5 mag, steepening to α = 0.340 ± 0.025 for R = 23.5 to 25.6 mag. The constant or steepening power law indicates asteroids fainter than R = 23.5 mag are abundant, contrary to some previous claims but consistent with theory.

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Role of Topocentric Parallax in Near-Earth Object Initial Orbit Determination

Zhai

Shao

Saini

et al. 2022

PASP

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Near-Earth Object (NEO) initial orbit determination typically uses astrometric measurements during a close approach over a time window much shorter than the orbital period of the NEO. The initial orbit is only weakly determined with dominant uncertainties in the distance of the NEO from the Earth. Topocentric astrometric measurements allow us to estimate NEO distances using observed nonlinear motions of the NEOs relative to observers, which come from the relative orbital motion of the NEOs to the Earth plus the topocentric parallax (parallax) from the diversity of observatory locations relative to the Earth center. We calculate the ratio of the contributions to the nonlinear motion from the relative orbital motion and the parallax to be approximately (TΔ/(day au))2, where T is the arc length measured in days and Δ is the distance of close approach. The dominant nonlinear motion for ranging the NEO comes from the relative orbital motion of the NEO to the Earth center, due to mainly the differential solar gravitational acceleration, when TΔ ≳ 1 day au and the parallax when TΔ ≲ 1 day au. This is confirmed by simulation data and supported by observational data of real NEOs. In the regime TΔ ≲ 1 day au, the orbit determination uncertainties are inversely proportional to the amplitude of the parallax. Introducing diversities of hour angles and observatory latitudes (especially alternating between extreme values) into scheduled follow-up observations can improve the parallax amplitude, thus the orbit accuracy. Most of the newly discovered NEOs are in this regime, we recommend optimizing parallax by properly scheduling observations when the NEO is very close to the Earth and using synthetic tracking to improve astrometry accuracy for initial orbit determination.

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Generalized Derivation of the RRV Method and Its Application

Cited by 5 publications

References 11 publications

A New Blind Asteroid Detection Scheme

A New Blind Asteroid Detection Scheme

The Flux Distribution and Sky Density of 25th Magnitude Main Belt Asteroids

Role of Topocentric Parallax in Near-Earth Object Initial Orbit Determination

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