306 Unitas

306 Unitas
	A three-dimensional model of 306 Unitas based on its light curve
Discovery
Discovered by	Elia Millosevich
Discovery date	1 March 1891
Designations
MPC designation	(306) Unitas
Pronunciation	/ˈjuːnɪtæs/
Alternative designations	A891 EA
Minor planet category	Main belt
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	124.78 yr (45575 d)
Aphelion	2.71480 AU (406.128 Gm)
Perihelion	2.0009 AU (299.33 Gm)
Semi-major axis	2.35785 AU (352.729 Gm)
Eccentricity	0.15139
Orbital period (sidereal)	3.62 yr (1322.4 d)
Mean anomaly	88.9729°
Mean motion	0° 16m 20.014s / day
Inclination	7.2779°
Longitude of ascending node	141.912°
Argument of perihelion	168.008°
Physical characteristics
Dimensions	46.70±2.3 km; 52.88 ± 3.48 km
Mass	(5.33 ± 5.77) × 1017 kg
Synodic rotation period	8.736 h (0.3640 d); 8.73875 h
Geometric albedo	0.2112±0.023; 0.211
Spectral type	S
Absolute magnitude (H)	8.96

306 Unitas is a typical main belt asteroid that was discovered by Elia Millosevich on 1 March 1891 in Rome. The asteroid was named by the director of the Modena Observatory in honor of the Italian astronomer Angelo Secchi (author of Unità delle forze fisiche)^[5] and the unification of Italy. It is classified as an S-type asteroid.

In the late 1990s, a network of astronomers worldwide gathered light curve data that was ultimately used to derive the spin states and shape models of 10 new asteroids, including (306) Unitas. The computed shape model for this asteroid is regular, while the light curve displays two maxima per rotation.^[3]^[6] Lightcurve data has also been recorded by observers at the Antelope Hill Observatory, which has been designated as an official observatory by the Minor Planet Center.^[7]

Measurements of the thermal inertia of 306 Unitas give an estimate range from 100 to 260 m⁻² K⁻¹ s^−1/2, compared to 50 for lunar regolith and 400 for coarse sand in an atmosphere.^[4]

Although 306 Unitas has an orbit similar to the Vesta family asteroids, it was found to be an unrelated interloper on the basis of its non-matching spectral type. ^{[citation needed]}

Orbir diagram of 306 Unitas

^ ^a ^b ^c ^d ^e "306 Unitas". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 11 May 2016.
^ ^a ^b Cite error: The named reference Carry2012 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference Durech2007 was invoked but never defined (see the help page).
^ ^a ^b ^c Cite error: The named reference Delbo2009 was invoked but never defined (see the help page).
^ Schmadel Lutz D. Dictionary of Minor Planet Names (fifth edition), Springer, 2003. ISBN 3-540-00238-3.
^ Durech, J.; Kaasalainen, M.; Marciniak, A.; Allen, W. H. et al. "Asteroid brightness and geometry", Astronomy and Astrophysics, Volume 465, Issue 1, April I 2007, pp. 331–337.
^ "Lightcurve Results". Archived from the original on 25 July 2011. Retrieved 9 March 2008.

[jpldata-1] "306 Unitas". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 11 May 2016.

[Carry2012-2] Cite error: The named reference Carry2012 was invoked but never defined (see the help page).

[Durech2007-3] Cite error: The named reference Durech2007 was invoked but never defined (see the help page).

[Delbo2009-4] Cite error: The named reference Delbo2009 was invoked but never defined (see the help page).

[5] Schmadel Lutz D. Dictionary of Minor Planet Names (fifth edition), Springer, 2003. ISBN 3-540-00238-3.

[6] Durech, J.; Kaasalainen, M.; Marciniak, A.; Allen, W. H. et al. "Asteroid brightness and geometry", Astronomy and Astrophysics, Volume 465, Issue 1, April I 2007, pp. 331–337.

[7] "Lightcurve Results". Archived from the original on 25 July 2011. Retrieved 9 March 2008.

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