319 Leona
en.wikipedia.org
319 Leona
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Re: 319 Leona
#2Is this as a heads up due to it's upcoming occultation of Betelgeuse or...?
Re: 319 Leona
#3> On 12 December 2023 Leona will occult Betelgeuse as seen from southern Europe.
Re: 319 Leona
#4It appears that astronomers are already preparing for the upcoming occultation of 319 Leona with Betelgeuse.
Researchers in this July 2023 presentation note:
> Leona’s Long Rotation Period (430h) complicates determination of its size and shape.
> So it is VERY IMPORTANT that some OTHER occultations by Leona be observed from multiple stations BEFORE December 12, to take best advantage of this unique opportunity.
[0] https://occultations.org/publications/rasc/2023/2023Dec12Leo...
And there is already at least one other set of observations reported on arXiv from a September 2023 occultation:
> The stellar occultation by (319) Leona on 13 September 2023 in preparation for the occultation of Betelgeuse
> This represents an extraordinary and unique opportunity to analyze the diameter and brightness distribution of Betelgeuse's photosphere with extreme angular resolution by studying the light curve as the asteroid occults the star from different points on Earth and at different wavelengths. Here we present observations of another occultation by Leona on 13 September 2023 to determine its projected shape and size in preparation for the December 12th event.
[1] https://arxiv.org/abs/2309.12272
(Amazing that it was posted ~8 days after the observations were made!)
Re: 319 Leona
#5Asteroids are very valuable targets in the solar system. It's because they're low delta vee to get to, and don't require high thrust since they don't have a deep and steep gravity well. This means electric propulsion can be used. Trip times might be long though.
One could extract materials from asteroids and bring them anywhere in space with low delta vee budgets.
Re: 319 Leona
#6That's quite the slow tumble. Back in high school a person in the area with a big fancy computerized telescope let a bunch of us physics students come up to do experiments. My partner and I decided to try to plot light curves for some famous asteroids and we were able to confirm that they were still rotating as last observed over periods that let us do this overnight.
Re: 319 Leona
#7Asteroids are very valuable targets in the solar system. It's because they're low delta vee to get to, and don't require high thrust since they don't have a deep and steep gravity well. This means electric propulsion can be used. Trip times might be long though. One could extract materials from asteroids and bring them anywhere in space with low delta vee budgets.
what is this particular asteroid made of? Iron?
Nevermind. It's a C-type asteroid.
https://en.wikipedia.org/wiki/C-type_asteroid
A chunk of coal mixed with pebbles
Re: 319 Leona
#8> On 12 December 2023 Leona will occult Betelgeuse as seen from southern Europe.
> On 12 December 2023 at about 01:09–01:27 UT, Leona will occult Betelgeuse as seen from southern Europe, Turkey, Greece and Sicily.[14] The 14th magnitude asteroid will occult Betelgeuse (block or reduce the light) for about 12 seconds. Betelgeuse is expected to dim by about 3 magnitudes.[16] Light curve studies of the event may help understand the distribution of brightness over the disk of Betelgeuse.
Betelgeuse is the 10th brightest star. It's dimming by a factor of ~16, but will still be visible, which surprises me. Does anyone know whether this is because (a) Betelgeuse's diffuse disc is wider than the asteroid's, (b) Betelgeuse will refract around the asteroid, or (c) something else? I'm guessing (b) but don't know much about this.
Re: 319 Leona
#9> On 12 December 2023 Leona will occult Betelgeuse as seen from southern Europe.
> On 12 December 2023 at about 01:09–01:27 UT, Leona will occult Betelgeuse as seen from southern Europe, Turkey, Greece and Sicily.[14] The 14th magnitude asteroid will occult Betelgeuse (block or reduce the light) for about 12 seconds. Betelgeuse is expected to dim by about 3 magnitudes.[16] Light curve studies of the event may help understand the distribution of brightness over the disk of Betelgeuse. Betelgeuse i…
Per wikipedia, dimming by 3 magnitudes means Betelgeuse will still be at +3-+4.6, which is probably too dim to be seen in a city, but still plenty bright.
Re: 319 Leona
#10> On 12 December 2023 Leona will occult Betelgeuse as seen from southern Europe.
> On 12 December 2023 at about 01:09–01:27 UT, Leona will occult Betelgeuse as seen from southern Europe, Turkey, Greece and Sicily.[14] The 14th magnitude asteroid will occult Betelgeuse (block or reduce the light) for about 12 seconds. Betelgeuse is expected to dim by about 3 magnitudes.[16] Light curve studies of the event may help understand the distribution of brightness over the disk of Betelgeuse. Betelgeuse i…
The primary source of the 3 magnitude dimming is this data: https://www.asteroidoccultation.com/2023_12/1212_319_82912_S...
It seems to be based on a very crude estimation, see the data near the bottom. It estimates Betelgeuse to have an angular diameter of 48.10 milli-arcseconds, and the astroid's angular diameter to 46.0 milli-arcseconds, which works out to a 11.7 dimming factor.