J/AJ/150/75ivo://CDS.VizieR/J/AJ/150/75doi:10.26093/cds/vizier.51500075CDSWaszczak A.Chang C.-K.Ofek E.O.Laher R.Masci F.Levitan D.,Surace J.Cheng Y.-C.Ip W.-H.Kinoshita D.Helou G.Prince T.A.,Kulkarni S.2016-01-20T12:51:13Z2015-11-23T13:18:45ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsurveysasteroidsapparent-magnitudeabsolute-magnitudeWe fit 54296 sparsely sampled asteroid light curves in the Palomar Transient Factory survey to a combined rotation plus phase-function model. Each light curve consists of 20 or more observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find that the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude, and other light-curve attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining ~53000 fitted periods. By this method we find that 9033 of our light curves (of ~8300 unique asteroids) have "reliable" periods. Subsequent consideration of asteroids with multiple light-curve fits indicates a 4% contamination in these "reliable" periods. For 3902 light curves with sufficient phase-angle coverage and either a reliable fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimodal though all correlate with the bond albedo and with visible-band colors. Comparing the theoretical maximal spin rate of a fluid body with our amplitude versus spin-rate distribution suggests that, if held together only by self-gravity, most asteroids are in general less dense than ~2g/cm^3^, while C types have a lower limit of between 1 and 2g/cm3. These results are in agreement with previous density estimates. For 5-20km diameters, S types rotate faster and have lower amplitudes than C types. If both populations share the same angular momentum, this may indicate the two types' differing ability to deform under rotational stress. Lastly, we compare our absolute magnitudes (and apparent-magnitude residuals) to those of the Minor Planet Center's nominal (G=0.15, rotation-neglecting) model; our phase-function plus Fourier-series fitting reduces asteroid photometric rms scatter by a factor of ~3.2015AJ....150...75Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/150/75CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/astorb : Orbits of Minor Planets (Bowell+ 2014)J/ApJ/759/49 : Jovian Trojan asteroids with WISE/NEOWISE: taxonomyJ/ApJ/741/68 : Main Belt asteroids with WISE/NEOWISE. I. (Masiero+, 2011)J/ApJ/740/65 : VLA search for 5GHz radio transients (Ofek+, 2011)J/AJ/142/60 : Palomar Transient Factory Orion Project (Van Eyken+, 2011)http://ptf.caltech.edu/ : Palomar Transient Factory surveyhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/150/75https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/150/75http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/150/75https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/150/75https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/150/75http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/150/75GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/AJ/150/75/table4Parameters describing Palomar Transient Factory (PTF) light curves with a reliable period or phase functionLCLight Curvemeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLCNum[1/9663] Light-curve identification number (1)meta.idintAst[99/400878] Asteroid number (IAU designation)meta.id;meta.mainintYear[9/14] Last two digits of opposition yearyrtime.epochintFlt[1/2] Photometric band (1=Gunn-g, 2=Mould-R)meta.code;instr.filterintNobs[20/499] Number of observations in the light-curvemeta.number;obsintmag[13.2/20.4] Median apparent magnitude (2)magphot.magfloatMJD0Modified Julian Date (MJD) time of first observationdtime.epoch;obsdoubleMJD1MJD time of final observationdtime.epoch;obsdoubleamin[0/32] Minimum-observed phase angle ({alpha}_min_)degpos.phaseAng;stat.minfloatamax[0.50/55.3] Maximum-observed phase angle ({alpha}_max_)degpos.phaseAng;stat.maxfloatNbin[1/13] Number of sampled phase-angle bins of 3-deg widthmeta.number;time.phaseintQ1[0/1] Reliability score from machine classifier (from 0=bad to 1=good)meta.code.qualfloatQ2[0/1] Manually-assigned reliability flag (0=bad, 1=good)meta.code.qualintQ3[0/1] Period reliability flag (0=bad, 1=good)meta.code.qual;time.periodintHMag[7.6/18.9] Absolute magnitude from G12 fitmagphys.magAbs;meta.modelledfloate_HMag[0/0.05] Uncertainty in HMagmagstat.error;phys.magAbs;meta.modelledfloatG12[0/1] Phase-function parameter G12 (3)stat.param;time.phasefloate_G12[-1/1] Uncertainty in G12 (4)stat.error;stat.param;time.phasefloatG[-0.3/0.7]? Phase-function parameter G (5)stat.param;time.phasefloatnullablebeta[-1.2/5]? Phase-function parameter {beta} (6)mag/degstat.param;time.phasefloatnullableC[0/0.8]? Phase-function parameter C (amplitude of the opposition surge) (6)magstat.param;time.phasefloatnullableAmp[0.02/1.31] Amplitude from G12 fitmagsrc.var.amplitude;meta.modelledfloatPer1[2/1918] Period from G12 fithtime.period;meta.modelleddoublee_Per1[0/2717] Uncertainty in Per1hstat.error;time.period;meta.modelleddoubleA11[-0.2/0.2] Fourier coefficient A1,1 from G12 fitmagsrc.var.amplitudefloatA12[-0.3/0.2] Fourier coefficient A1,2 from G12 fitmagsrc.var.amplitudefloatA21[-0.6/0.6] Fourier coefficient A2,1 from G12 fitmagsrc.var.amplitudefloatA22[-0.6/0.6] Fourier coefficient A2,2 from G12 fitmagsrc.var.amplitudefloatRpeak[0/1] Ratio of two peak heights in folded rotation curve (7)phot.flux;arith.ratiofloatchi2[0.34/3] Reduced chi-squared of the fit ({chi}^2^_red_)stat.fit.chi2;stat.fit.param;meta.modelledfloatcosmic[0/0.077] The "cosmic error" (8)magstat.errorfloatrms[0/0.09] Root-mean-square residual of observations with respect to the fitmagstat.fit.residual;stat.fit.param;obsfloatPer2[1/380]? Reference period (9)htime.periodfloatnullableDiam[0.9/133]? Diameter derived from thermal infrared (IR) data (10)kmphys.size.diameterfloatnullablee_Diam[0/4.25]? Uncertainty in Diamkmstat.error;phys.size.diameterfloatnullableAlb[0/0.2]? Bond albedo (11)phys.albedofloatnullablee_Alb[0/0.0363]? Uncertainty in bond albedostat.error;phys.albedofloatnullableCI[0/1]? Color-based taxonomic index (0=C-type asteroid, 1=S-type asteroid; See Section 6 for details)meta.code;phot.colorfloatnullablePI[0/1]? Photometry-based taxonomic index (0=C-type, 1=S-type; See Section 6.3.1 for details)meta.code;phot.colorfloatnullableJ/AJ/150/75/table5Individual Palomar Transient Factory (PTF) photometric observations in each light curverecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLCNum[1/9663] Light-curve identification number (1)meta.id;meta.maininttau[4907/6764] Light-time-corrected observation epoch ({tau})dtime.epoch;obsdoubleHDist[1/13.7] Heliocentric distanceAUpos.distance;pos.heliocentricdoubleGDist[0.2/14.1] Geocentric distance ({Delta})AUpos.distance;pos.geocentricdoublealpha[0/56] Solar phase angle ({alpha})degpos.phaseAngfloatmag1[6/26] Apparent magnitude (2)magphot.magfloate_mag1[0/0.9] Uncertainty in mag1magstat.error;phot.magfloatemag1[0/0.9] Uncertainty in mag1 with cosmic-errormagphot.magfloatmag2[1.6/19.4] Magnitude corrected for distance and G_12_ phase functionmagphot.magfloatmag3[2.4/20.1] Magnitude corrected for distance and rotation (G_12_ fit)magphot.magfloatRes[-1/1.3] Residual with respect to the G_12_ fitmagstat.fit.residual;stat.fit.param;meta.modelledfloatPhase[0/1] Rotational phase from 0 to 1 (G_12_ fit)time.phasefloat