The radius of Betelgeuse is thought to be around a thousand times greater than the sun and would reach beyond the orbit of Jupiter if it was placed at the center of our solar system. The following image by the European Southern Observatory shows the size comparison of Betelgeuse compared to the planets in our solar system.
The overlaid annotation shows how large the star is compared to our Solar System. The Star Betelgeuse Where is Betelgeuse located? Betelgeuse pulsates because it has an unstable stellar atmosphere. When it contracts, it absorbs more of the energy that passes through it.
As a result, its atmosphere heats up and expands. When the star expands, the atmosphere becomes less dense and cools down, which leads to another period of contraction. Image: ESO, P. Kervella, Digitized Sky Survey 2 and A. Because the star is rapidly losing mass, its surface is obscured by a large envelope of ejected material, approximately times larger than the star itself, which makes measurements even more difficult.
In , two close companions were discovered in orbit around Betelgeuse, but have not been confirmed by research in the years since. Betelgeuse is easy to find in the sky because it is part of a prominent winter constellation , Orion the Hunter.
For observers in the northern hemisphere, Betelgeuse rises in the east just after sunset in January.
In March, it is due south early in the evening. By May, the star only briefly shows up on the western horizon after sunset. A few months later, it can be seen appearing on the eastern horizon just before dawn. Betelgeuse has reached a late stage of evolution and is expected to end its life in a supernova event at some point within the next million years.
The red supergiant will most likely go out as a Type II supernova. The supernova may brighten to a visual magnitude of over a couple of weeks, which would make it outshine the Moon, cast shadows in the night, and be visible in daylight. The supernova would stay at that intensity for two to three months before dimming. While Betelgeuse is far too distant to do any damage to Earth, the supernova will certainly give us a very bright spectacle in the sky.
Neutrinos and other forms of radiation will not reach us until years after the supernova and will not affect terrestrial life. Supernovae generally must be within 25 light years to cause any significant damage to Earth. At light years, Betelgeuse is more than 25 times that distance. Betelgeuse has evolved off the main sequence and has expanded and cooled to become a red supergiant. Even though it is a relatively young star, it has likely used up the hydrogen at its core, which is causing it to contract, its temperature to rise, and its density to increase.
Consequently, Betelgeuse has started fusing helium into carbon and oxygen. At some point, it will collapse and go supernova. Most likely, it will leave behind a neutron star roughly 20 kilometres in diameter.
Mass is a key factor when predicting how a star will end its life. The exact mass of Betelgeuse is uncertain, but most astronomers who have investigated the star agree that it has more than 10 solar masses. They are similar to Mira stars in their periodicity but are distinguished by their smaller amplitude. A typical member of this subgroup is the star Z Aqr. SRb — These are also small amplitude stars but with less regularity in their light variations than the SRa stars. The SRb stars have periods longer than 20 days and V amplitudes less than 2.
Although the form of a period is evident, it becomes inoperative from time to time. SRc — These are the Supergiants which are extremely luminous stars. They have low amplitudes and occasional standstills. Betelgeuse is classsified as an SRc type variable. SRd — Yellow giants and supergiants of spectral classes F-K: not a very homogneous group.
They are much hotter than the other semiregulars and show irregularities at times. Betelgeuse is a difficult star to observe due to its redness, lack of well-placed i. It is also best to compare a red star with another red star at about the same altitude. Although a challenge to observe, it is encouraging that Betelgeuse is so bright and easy to find. Observers could create an observing program in which you observe Alpha Ori in the coming months once every week.
Try not to compare your observations with those in our WebObs search or Light Curve Generator to avoid bias in your estimate and see if you can really detect the light variability in this supergiant. Photoelectric photometry observers are especially encouraged to observe this star of small amplitude. Next year, with the first sight of Orion in your sky, be sure to observe Betelgeuse again. The name "Betelgeuse" is a corrupt derivative of the original Arab nomenclature due to repeated transcriptions and transliterations over many centuries.
According to George A. The "original" meaning of this word designates a black sheep with a white spot in the center of its body, however scholars have interpreted the meaning to come from a similar Arabic word, jauz , which means "the center of anything" or "the central one". Davis believes that the true origin of the name is Yad al-Jawza' , "the forefoot of the white-belted sheep," one diacritical point missing under the ya in Yad resulting in the transliterated syllable bad or bed.
The change of a d to a t needs no explanation, and so evolved the current name, "Betelgeuse". On an interesting cinematical side note, this "letter to the editor" by Michael McDowell from Los Angeles, California, appeared in the April issue of Sky and Telescope magazine. Betelgeuse: The Movie. During the four years I spent with the project in Hollywood, I was repeatedly pleased — and somewhat astonished — by people who responded to the title Beetlejuice with the question, "Oh, you mean like the star?
From the island of La Palma in the Canaries archipelago, this image clearly shows Orion with Betelgeuse in the top left corner. Credit: A. Vannini, G. Li Causi, A. Ricciardi, A.
Garatti At minimum brightness, as in and , the magnitude may drop below 1. Lights, Camera, Action. However, the results of their measurements are not dependable. Later observations yielded an angular diameter between 0. Betelgeuse is one of the four Orion stars selected for navigation. The other three navigational stars in the constellation are Rigel , Bellatrix and Alnilam. These were the first such images of a star other than the Sun at the time.
The images were part of a study conducted by a team of astronomers at the Mullard Radio Astronomy Observatory in Cambridge and the Palomar Observatory in California. The observations also revealed the presence of a dust halo at least 0. A study published in , conducted in by a team at the Mullard Radio Astronomy Observatory and the lnstitute of Astronomy in Cambridge, did not find evidence of the brightness asymmetries, only a strongly limb-darkened, but symmetric disc.
Limb darkening is a gradual decrease in the brightness of a stellar disk seen from the centre to the limb or edge. The ultraviolet image had a significantly better resolution than those taken by ground-based telescopes. This is the first direct image of a star other than the Sun.
Called Alpha Orionis, or Betelgeuse, the star is a red super giant, a Sun-like star nearing the end of its life. The observations also yielded a rotation period of 17 years, with a rotational speed of 1. The vast dust and gas shells extend almost 20, astronomical units away from the star. Lim, C. Carilli, S.
White, A. Beasley, and R. The gaseous envelope extends for about 10 to 40 astronomical units from the photosphere and is asymmetrical. Radio-telescope observations made in confirmed that Betelgeuse has a dense and very complex atmosphere which is many times larger than the star itself.
The lower-temperature gas cools as it is propelled from the surface into the atmosphere. The images revealed that it was accelerating outward. The dust envelope was given a radius estimate between 0. The size of the two outer carbon monoxide shells is also uncertain, but observations in detected one shell 1. Betelgeuse may be one of the most studied stars in the sky, but its birthplace is still a mystery.
A study published in March proposed that the star was most likely a member of a multiple star system within the Orion Ob1a subgroup. However, a study published in uncovered a previously unknown group, the Taurion OB association, and proposed that, based on its velocity and proximity to the group, Betelgeuse may belong to this association instead.
The Taurion OB association occupies an area of about 20 by 15 degrees between the constellations Orion and Taurus , and includes 36 B stars with an average estimated distance of only parsecs about light years. The bow shock is about three light years in diameter and the mass of the bow shock shell is believed to be low, indicating that the bow shock was created relatively recently in the past 30, years and that Betelgeuse has not been a red supergiant for very long.
Betelgeuse is one of the largest visible stars. For comparison, the current size record holder, the red supergiant UY Scuti , has an estimated radius about 1, times that of the Sun, which makes it almost twice as large as Betelgeuse. Betelgeuse has up to nine dim line-of-sight companions at a separation of 1 to 4 minutes of arc. All the stars are fainter than 10th magnitude.
Betelgeuse itself is believed to be a single star, one not associated with any companions, clusters or molecular clouds. It was once suspected to have two spectroscopic companions, which were indicated by the polarization data from to , but later observations, including high-resolution interferometry, found no evidence of close companions. Betelgeuse is often used or referenced in works of fiction. Its many appearances in literature include H.
The other candidate is the blue-white Bellatrix , the left shoulder of Orion.
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