397 Vienna

{{Short description|Main-belt asteroid}}

{{Use dmy dates|date=October 2019}}

{{Infobox planet

| minorplanet = yes

| background = #D6D6D6

| name = 397 Vienna

| discoverer = Auguste Charlois

| image = Орбита астероида 397.png

| caption = Orbital diagram

| discovered = 19 December 1894

| mpc_name = (397) Vienna

| pronounced = {{IPAc-en|v|i|'|ɛ|n|ə}}

| alt_names = 1894 BM

| named_after = Vienna

| mp_category = Main belt

| epoch = 31 July 2016 (JD 2457600.5)

| orbit_ref =

| semimajor = {{cvt|2.63671|AU|Gm}}

| perihelion = {{cvt|1.98686|AU|Gm}}

| aphelion = {{cvt|3.28657|AU|Gm|lk=on}}

| eccentricity = 0.24646

| period = {{cvt|1563.8|days|years|2|order=flip}}

| inclination = 12.8534°

| asc_node = 227.935°

| arg_peri = 139.975°

| mean_anomaly = 202.358°

| dimensions = {{val|49.032|1.055|ul=km}}

| mass =

| density =

| rotation = {{Convert|15.48|h|d|abbr=on|lk=on}}

| spectral_type =

| abs_magnitude = 9.31

| albedo = {{val|0.1776|0.015}}

| mean_motion = {{Deg2DMS|0.230203|sup=ms}} / day

| observation_arc = {{cvt|42900|days|years|2|order=flip}}

| uncertainty = 0

}}

397 Vienna is a typical Main belt asteroid. It was discovered by French astronomer Auguste Charlois on 19 December 1894 in Nice. It was most likely named after the city of Vienna, Austria. This object is orbiting the Sun at a distance of {{val|2.64|ul=AU}} with an orbital eccentricity (ovalness) of 0.246 and a period of {{cvt|1563.8|days|years|2|disp=out}}. The orbital plane is inclined at an angle of 12.85° to the ecliptic.

Photometric observations from multiple sites during 2017 were combined to produce an irregular light curve showing a rotation period of {{val|15.461|0.001|u=hours}} with a luminosity amplitude of {{val|0.16|0.02}} in magnitude. This result is consistent with previous measurements. The Tholen spectral type of this object is S and the SMASSII spectral type is K. Although the 'S' class suggests a stony composition, the latter class is consistent with carbonaceous chondrite meteorites. Infrared observations from NEOWISE indicate a diameter of {{val|49|u=km}}.