J/A+A/639/A134 The large TNO 2002 TC302 (Ortiz+, 2020)
The large Trans-Neptunian object 2002 TC302 from combined stellar occultation
photometry and astrometry data.
Ortiz J.L., Santos-Sanz P., Sicardy B., Benedetti-Rossi G., Duffard R.,
Morales N., Braga-Ribas F., Fernandez-Valenzuela E., Nascimbeni V.,
Nardiello D., Carbognani A., Buzzi L., Aletti A., Bacci P., Maestripieri M.,
Mazzei L., Mikuz H., Skvarc J., Ciabattari F., Lavalade F. Scarfi G.,
Mari J.M., Conjat M., Sposetti S., Bachini M., Succi G., Mancini F.,
Alighieri M., Dal Canto E., Masucci M., Vara-Lubiano M., Gutierrez P.J.,
Desmars J., Lecacheux J., Vieira-Martins R., Camargo J.I.B., Assafin M.,
Colas F., Beisker W., Behrend R., Mueller T.G., Meza E., Gomes-Junior A.R.,
Roques F., Vachier F., Mottola S., Hellmich S., Campo Bagatin A.,
Alvarez-Candal A., Cikota S., Cikota A., Christille J.M., Pal A., Kiss C.,
Pribulla T., Komzik R., Madiedo J. M., Charmandaris V., Alikakos J.,
Szakats R., Farkas-Takacs A., Varga-Verebelyi E., Marton G., Marciniak A.,
Bartczak P., Butkiewicz-Bak M., Dudzinski G., Ali-Lagoa V., Gazeas K.,
Paschalis N., Tsamis V., Guirado J.C., Peris V., Iglesias-Marzoa R.,
Schnabel C., Manzano F., Navarro A., Perello C., Vecchione A.,
Noschese A., Morrone L.
<Astron. Astrophys. 639, A134 (2020)>
=2020A&A...639A.134O 2020A&A...639A.134O (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Positional data ; Ephemerides ;
Occultations ; Photometry, CCD
Keywords: Kuiper belt objects: individual: 2002 TC302 - Kuiper belt: general -
techniques: photometric - occultations - astrometry
Abstract:
On 28th January 2018, the large Trans-Neptunian Object 2002 TC302
occulted a mv∼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 TNO 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 can be
obtained, compatible with the near misses. The resulting ellipse has
major and minor axes of 543±18km and 460±11km, 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 84km 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 ∼300km 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 TC302 has a satellite. The
best occultation light curves do not show any signs of ring features
or any signatures of a global atmosphere.
Description:
Table 1 includes the data from the astrometric monitoring runs for
2002 TC302 carried out to narrow down the shadow path uncertainty,
in October, November, December 2017 and January 2018 with the Sierra
Nevada 1.5m telescope (Granada, Spain) and the Calar Alto 1.2m
telescope (Almeria, Spain). The astrometric catalog used for the
occultation prediction was Gaia DR1.
Tables 2 and 3 include, respectively, all the photometry and
astrometry of 2002 TC302 analyzed, from 2014 to 2019. The astrometry
was derived with respect to the Gaia DR2 catalog (Cat. I/345).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 80 497 *Astrometry for prediction
tablea2.dat 22 875 All photometry
tablea3.dat 80 875 *All astrometry
--------------------------------------------------------------------------------
Note on tablea1.dat, tablea3.dat: follow the Minor Planet Center format:
https://minorplanetcenter.net/iau/info/OpticalObs.html
--------------------------------------------------------------------------------
See also:
J/PAZh/30/692 : Occultations of stars by large TNO 2004-2014 (Denissenko, 2004)
J/A+A/468/L13 : Photometry of the trans-Neptunian object 2005FY9 (Ortiz+, 2007)
Byte-by-byte Description of file: tablea1.dat tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
5- 11 I7 --- Name [0084522] Designation (1)
15 A1 --- Type [C] CCD observation
16- 19 I4 yr Obs.Y Year of observation (2)
21- 22 I2 "month" Obs.M Month of observation (2)
24- 31 F8.5 d Obs.D Day of observation (2)
33- 34 I2 h RAh Right ascension (J2000)
36- 37 I2 min RAm Right ascension (J2000)
39- 44 F6.3 s RAs Right ascension (J2000)
45 A1 --- DE- Declination sign (J2000)
46- 47 I2 deg DEd Declination (J2000)
49- 50 I2 arcmin DEm Declination (J2000)
52- 56 F5.2 arcsec DEs Declination (J2000)
66- 70 F5.2 mag Rmag Observed magnitude in R band
72 A1 --- Band [R] Band
78- 80 A3 --- ObsCode Observatory code (3)
--------------------------------------------------------------------------------
Note (1): Zero-padded, right-justified packed minor planet number.
Note (2): Date and UTC time of the mid-point of observation. This times are not
corrected for light travel time.
Note (3): Observatory codes can be found in
https://minorplanetcenter.net/iau/lists/ObsCodes.html
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 F14.6 --- JD Julian Date (1)
17- 22 F6.4 --- Flux Normalized flux
--------------------------------------------------------------------------------
Note (1): Julian Date of the mid-point of observation, corrected for light
travel time.
--------------------------------------------------------------------------------
Acknowledgements:
Jose Luis Ortiz, ortiz(at)iaa.es
Monica Vara-Lubiano, mvara(at)iaa.es
(End) Monica Vara-Lubiano [IAA-CSIC], Patricia Vannier [CDS] 02-Jul-2020