895 Helio

895 Helio is a large dark outer main-belt asteroid^[4] about 150 km in diameter. It was discovered on 11 July 1918 by German astronomer Max Wolf.^[2] It is named after the element helium, whose spectrum was studied by Friedrich Paschen and Carl David Tolmé Runge, with the asteroid being named by Paschen at Wolf's request; the name helium itself comes from Helios, the Greek god of the Sun.

895 Helio

Discovery
Discovered by	Max Wolf
Discovery site	Heidelberg
Discovery date	11 July 1918
Designations
MPC designation	(895) Helio
Pronunciation	/ˈhiːlioʊ/[1]
Alternative designations	1918 DU
Adjectives	Helian /ˈhiːliən/
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	109.79 yr (40100 days)
Aphelion	3.6686 AU (548.81 Gm)
Perihelion	2.7362 AU (409.33 Gm)
Semi-major axis	3.2024 AU (479.07 Gm)
Eccentricity	0.14558
Orbital period (sidereal)	5.73 yr (2093.2 d)
Mean anomaly	241.229°
Mean motion	0° 10m 19.164s / day
Inclination	26.077°
Longitude of ascending node	264.704°
Argument of perihelion	178.108°
Earth MOID	1.75069 AU (261.899 Gm)
Jupiter MOID	1.60187 AU (239.636 Gm)
TJupiter	3.019
Physical characteristics
Mean diameter	148.43 ± 5.02 km[3] 109.568±1.987 km[2]
Mass	(9.87 ± 6.05) × 1018 kg[3]
Mean density	5.76 ± 3.58 g/cm3[3]
Synodic rotation period	9.3959 h (0.39150 d)
Sidereal rotation period	9.3959 h[2]
Geometric albedo	0.0420±0.002[2]
Spectral type	FCB/B[2]
Absolute magnitude (H)	8.3[2]

This is a B-type asteroid.^[2] The best spectral analog for 895 Heloi is the iron rich pyroxene mineral hedenbergite. It shares similar orbital properties with the 31 Euphrosyne asteroid family, but is most likely an interloper.^[5] Light curve analysis provides a rotation period of 9.4 hours.^[4]

References

1. "helio". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
2. "JPL Small-Body Database Browser: 895 Helio". Jet Propulsion Laboratory. Retrieved 3 May 2016.
3. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
4. Polakis, Tom; Skiff, Brian A. (October 2016), "Lightcurve Analysis for Asteroids 895 Helio and 1108 Demeter", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers, 43 (4): 310, Bibcode:2016MPBu...43..310P.
5. Yang, B.; et al. (November 2020), "Physical and dynamical characterization of the Euphrosyne asteroid family", Astronomy & Astrophysics, 643: 9, arXiv:2009.04489, Bibcode:2020A&A...643A..38Y, doi:10.1051/0004-6361/202038567, A38

External links

• 895 Helio at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 895 Helio at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters