View allAll Photos Tagged absorption
Title: Absorption Apparatus
Digital Publisher: Digital: Cushing Memorial Library and Archives, Texas A&M University, College Station, Texas
Physical Publisher: Physical: Graphic Services, Texas A&M University
Description: year (coverage): Unknown
Date Issued: 2011-08-17
Dimensions: 4 x 5 inches
Format Medium: Photographic negative
Type: image
Identifier: Photograph Location: Graphic Services Photos, Box 36, File 36-561
Rights: It is the users responsibility to secure permission from the copyright holders for publication of any materials. Permission must be obtained in writing prior to publication. Please contact the Cushing Memorial Library for further information
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Look at those hands. Look at that concentration. I just found out recently from her mother that those grapes aren't actually really edible...they're too sour. She ate the entire bunch with nary a pause. Look, she insisted that I picked them for her...how was I to know?
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This bee was so 'into' his work I was able to give the flower (a salvia) a gentle squeeze after I took this shot, and he came out looking rather peeved...
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Sonata Class A rated Acoustic panels are used within a wide variety of buildings to reduce reverberation and give a suitable acoustic environment.
Hapuu pulu - Fiddleheads of this tree fern are covered with absorptive pulu (golden wool) that protects its new growth from drying. Softe pulu is also useful as a dressing for wounds and abrasions - Very slow growing trunk about an inch a year.
- Cibotium glaucum is a Hawaiian endemic tree fern. It is particularly abundant on the island of Hawai'i, but is found on all the major Hawaiian Islands. It is most common is moist to wet forests at elevations ranging from 1,500 to 5,000 feet.
Kilauea Crater Hike - Hilo, Big Island of Hawaii
Suspended time and absorption are central in our performative work. We perform „engrossed in an activity as if in denial of an audience“. We keep still. We move according to a choreographed path. We keep close to each other, we touch each other, we lie on the floor. From one tableau to the next. Holding the image for few minutes. One of us lies on a wooden plank. The whole leg, buttocks and lower back rest on the plank. Only shoulders and head touch the floor. The second figure is already doing a shoulderstand, bending the left knee and simultaneously stretching and leaning the right leg slightly over the head. The stretched leg remains leaning… The piece is inspired by the long scene in the sculpture garden at the Museum of Modern Art in New York from the film „Shadows“ by John Casavettes; Stills from Bob Fosse’s „All that Jazz“; photos of works by Yvonne Rainer and Rudolph von Laban and Kinesiology, physical therapy exercises.
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My photo walk of July 29, 2023, Lyon, France, district of La Croix Rousse, with my Pentacon Praktica VLC3 camera, a German 35mm SLR of the 70's fitted here with a normal lens Pentacon "electric" 1:1.8 f=50mm.
For this session, I loaded an Ilford HP5+ 36-exposure film and I fitted for all the views a 49mm pale yellow (coefficient. x1.5) screw-on filter on the lens.
I exposed the film at 400 ISO for the Praktica CdS cell that gave similar measuring compared to my trusted Minolta Autometer III with 250 ISO setting to compensate the filter absorption. The Autometer III Minolta light meter was fitted with a 10° finder for selective measurements privileging the shadow areas but I mostly used the camera measuring that is quite reliable.
Focusing was done using the Pentacon focusing screen with a central stigmometer.
Shutter speeds from 1/1000s to 1/125s and f/16 to f/5.6 were used along the session between 2pm and 4PM and a very changing light due to clouds passing by.
Rue Diderot, July 29, 2023
69001 Lyon
France
After exposure, the film was revealed using Adox Adonal (Agfa Rodinal) developper at dilution 1+25 and 20°C for 6 min. The film was then digitalized using a Sony A7 body fitted to a Minolta Slide Duplicator installed on a Minolta Auto Bellows III with a lens Minolta Bellow Macro Rokkor 50mm f/3.5. The RAW files obtained were processed without intermediate files in LR and edited to the final jpeg pictures.
All views (plus some smartphone documentary pictures) of the film are presented in the dedicated album either in the printed framed versions and unframed full-size jpeg
About the camera :
The Praktica VLC is of the 3rd generation (VLC3, 1978-1981) and was manufactured by "VEB Pentacon" (formally Zeiss-Ikon) in Dresden, Germany. It came with a number of orignal Pentacon accessories including, a shade hood for its normal lens Pentacon "electric Multi-coated" 1:1,8 f=50mm, a waist finder, a loup magnification finder, and the regular pentaprism. There are also 6 different focusing screens, the Pentacon hot shoe for a flash, lens and body caps, and a Praktica ever-ready case.
The camera has a CdS photometric circuitry powered by an unusual 4.5V battery that I replaced by a set of 3 LR44 alkaline batteries in series. As the ASAHI PENTAX Spomatic SP, the bridge circuit is insensitive to the voltage difference. To be independent of the finders, the cell is functioning behind the mirror as in the Topcon Super D or the Miranda Auto Sensorex EE.
This Praktica operates at full aperture using an electrical transmission of the aperture using 3 contacts on the M42 lens mount. It could however operates any non electric M42 lenses at real aperture too by acting on the rotary switch at the top left. As for the other Praktica of the L series the shutter is made of vertical steel curtains making the X-flash synchro at about 1/125 s.
Overall Pentacon produced 85 000 Praktica VLC between 1974 and 1981 among about 3 millions of Praktica "L" (LLC MTL TL L etc).
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Mike Thompson overseas the backhoe digging a 12 foot trench to test for soil water absorption rates.
Hunter Alumni Quarterly, Pg. 8, Fall 1964, Archives & Special Collections, Hunter College Libraries, Hunter College of the City University of New York, New York City.
For more information:
Bnei Menashe aliyah and arrival ceremony at Ben Gurion Airport, with the Minister of Absorption.
Photos taken by Laura Ben-David
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My photowalk with my Semflex Standard 3.5, a French TLR camera year 1959, Lyon, France June 18, 2024.
The camera was equipped with a Semflex yellow filter x2 and the Semflex metal shade hood. An Ilford PanF+ 120 film was loaded and exposed for 32 ISO (Instead of 50 ISO to compensate in part the filter absorption) using a Minolta Autometer III equipped with a 10° finder for selective measures privileging the shadow areas.
Typically I used the 1/100s (one at 1/50s) with aperture ranging from f/8 to f/4.5.
June 18, 2024
69004 Lyon
France
After the view #12 exposed, the film was fully rolled to the taking spool and was developed in a Paterson tank with a spiral adapted to the 70mm large film. 500 mL of Adox Adonal (Agfa Rodinal) developer were prepared at the dilution 1+25 and the film processed for 6min at 20°C.
Digitizing was made using a Sony A7 camera (ILCE-7, 24MP) held on a Minolta vertical macro stative device and adapted to a Minolta MD Macro lens 1:3.5 f=50mm. The light source was a LED panel (approx. 4x5') CineStill Cine-lite fitted with film holder "Lobster" to maintain flat the 70mm films.
The RAW files obtained were inverted within LR and edited to the final jpeg pictures without intermediate file. They are presented either as printed files with frame or the full size JPEG.
About the camera and lenses :
New in my camera collection this French Semflex TLR year 1959-1960 equipped with f=75mm SOM Berthiot lenses.
The SEM company ("Société des Etablissements Modernes de Mécanique") was founded in France by Paul Royet in 1946, in the small city of Aurec near Saint-Etienne (Loire). The SEM camera's was known essentially for the TLR Semflex that were a great commercial success in France until the 70's. The camera's are constructed around an injected aluminum alloy chassis, very resistant and rigid permitting precise optical alignments. The focusing mechanism is made of a cam system like the Rolleiflex giving an accurate and smooth focusing. SEM constructed their own shutters called Orec with 5 leaves capable of the 1/400s to 1s with B.
Semflex received in majority French optics Berthiot with 3 or 4 lenses (Tessar type). Some camera's were also mounted with Angénieux lenses.
Semflex were trusted TLR camera's used by amateurs and for professional purposes. From 1949 to 1976, 171.000 Semflex were produced in many different types and versions.
My Semflex in a middle grade version Standard 3.5 type-10 (1959-1960). It was the last version mounted with the 3-lens SOM Berthiot 1:3.5 f=75mm. I got the camera with set of accessories and several documents including the user manual of the Semflex Standard 4.5 versions. The accessories include a leather SEM ever-ready bag, a Semflex push-on shade hood, a Semflex push-on yellow filter x2 in its original box, and close-focusing lenses. The 1D one is constructed with a prism for the finder lens that compensates the parallax in the zone 1m to 0.5m.
The decorative ring around each lenses can also receive push-on accessories in 36mm diameter as the FOCA or Leitz 36mm filter series. I adapted two protective lens caps from Kodak film canister snapped covers.
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5 Jan 2025, 03:33 UT; Spotsylvania, Virginia USA. Bortle 4.5 zone.
Celestron C8 SCT at f/10.1. Orion Atlas AZ/EQ-G mount. Mallincam DS26cTEC camera, bin 1x1, exposure 16s, single frame, Optolong L'eNhance filter, no guiding, no calibration frames, sensor -5°C. Captured in Sharpcap Pro. Processed in PixInsight and Photoshop.
IDENTIFICATION OF Rigel BC
In the absence of a plate-solved location for Rigel BC the following information was considered:
1. Positive -- Published position angle (202° East of North) is consistent with labelled BC. Per ASTAP this image does not have standard orientation, e.g. it does not show North in the standard position -- up (0°). A corrected image would be rotated 7° and flipped on the horizontal axis for standard alignment with North, which puts the labelled star near the correct position.
2. Negative -- The brightest star in the field (besides Rigel A) is magnitude 6.35 and the nearby dimmer stars are approx. magnitude 10. The image of the labelled star BC (magnitude 7.5) is between them in size (brightness) but appears closer to magnitude 10 than 6.
3. Negative -- The separation of A from labelled BC in the image is roughly estimated from the image at 1 arcmin, not the expected 0.16 arcmin (9.5 arcsec).
4. Positive -- It is consistent with other posted amateur images of Rigel A & B.
BOTTOM LINE
I have 80% confidence that Rigel BC is correctly identified in this image, but another star could be obscured in the asymmetrical flare. An occulting bar may be used to verify dim Rigel BC against its brilliant companion in a subsequent image.
Appearance: Bright light blue star (Rigel A) and dim companions (Rigel B, C, and D), with adjacent variable star λ Eri (magnitude 6.35) at 3:00 position. The severe halo/flare around Rigel may be due to the filter, and may be asymmetrical due to moderate sensor tilt in the system.
Clouds: clear
Transparency: average
Seeing: below average
Apparent Magnitude (USNO): A 0.5-0.18, BC 7.5-7.6
Separation A-BC: 9.5 arcsec
Image scale:
Moon age, illuminated: xx, xx
Azimuth: xx°
Altitude: xx°
from Wikipedia
Rigel is a blue supergiant star in the constellation of Orion. It has the Bayer designation β Orionis, which is Latinized to Beta Orionis and abbreviated Beta Ori or β Ori. Rigel is the brightest and most massive component – and the eponym – of a star system of at least four stars that appear as a single blue-white point of light to the naked eye. This system is located at a distance of approximately 860 light-years (260 pc) from the Sun.
A star of spectral type B8Ia, Rigel is 120,000 times as luminous as the Sun, and is 18 to 24 times as massive, depending on the method and assumptions used. Its radius is more than seventy times that of the Sun, and its surface temperature is 12,100 K. Due to its stellar wind, Rigel's mass-loss is estimated to be ten million times that of the Sun. With an estimated age of seven to nine million years, Rigel has exhausted its core hydrogen fuel, expanded, and cooled to become a supergiant. It is expected to end its life as a type II supernova, leaving a neutron star or a black hole as a final remnant, depending on the initial mass of the star.
Rigel varies slightly in brightness, its apparent magnitude ranging from 0.05 to 0.18. It is classified as an Alpha Cygni variable due to the amplitude and periodicity of its brightness variation, as well as its spectral type. Its intrinsic variability is caused by pulsations in its unstable atmosphere. Rigel is generally the seventh-brightest star in the night sky and the brightest star in Orion, though it is occasionally outshone by Betelgeuse, which varies over a larger range.
A triple-star system is separated from Rigel by an angle of 9.5 arc seconds. It has an apparent magnitude of 6.7, making it 1/400th as bright as Rigel. Two stars in the system can be seen by large telescopes, and the brighter of the two is a spectroscopic binary. These three stars are all blue-white main-sequence stars, each three to four times as massive as the Sun. Rigel and the triple system orbit a common center of gravity with a period estimated to be 24,000 years. The inner stars of the triple system orbit each other every 10 days, and the outer star orbits the inner pair every 63 years. A much fainter star, separated from Rigel and the others by nearly an arc minute, may be part of the same star system.
In 2016, the International Astronomical Union (IAU) included the name "Rigel" in the IAU Catalog of Star Names. According to the IAU, this proper name applies only to the primary component A of the Rigel system. The system is listed variously in historical astronomical catalogs as H II 33, Σ 668, β 555, or ADS 3823. For simplicity, Rigel's companions are referred to as Rigel B, C, and D; the IAU describes such names as "useful nicknames" that are "unofficial". In modern comprehensive catalogs, the whole multiple star system is known as WDS 05145-0812 or CCDM 05145–0812.
The designation of Rigel as β Orionis (Latinized to beta Orionis) was made by Johann Bayer in 1603. The "beta" designation is usually given to the second-brightest star in each constellation, but Rigel is almost always brighter than α Orionis (Betelgeuse). Astronomer J.B. Kaler speculated that Bayer assigned letters during a rare period when variable star Betelgeuse temporarily outshone Rigel, resulting in Betelgeuse being designated "alpha" and Rigel designated "beta". However, closer examination of Bayer's method shows that he did not strictly order the stars by brightness, but instead grouped them first by magnitude, then by declination. Rigel and Betelgeuse were both classed as first magnitude, and in Orion the stars of each class appear to have been ordered north to south.
Rigel has many other stellar designations taken from various catalogs, including the Flamsteed 19 Orionis (19 Ori), the Bright Star Catalogue entry HR 1713, and the Henry Draper Catalogue number HD 34085. These designations frequently appear in the scientific literature,[ but rarely in popular writing. Rigel is listed in the General Catalogue of Variable Stars, but since its familiar Bayer designation is used instead of creating a separate variable star designation.
Rigel is an intrinsic variable star with an apparent magnitude ranging from 0.05 to 0.18. It is typically the seventh-brightest star in the celestial sphere, excluding the Sun, although occasionally fainter than Betelgeuse. Rigel appears slightly blue-white and has a B-V color index of −0.06. It contrasts strongly with reddish Betelgeuse.
Culminating every year at midnight on 12 December, and at 9:00 pm on 24 January, Rigel is visible on winter evenings in the Northern Hemisphere and on summer evenings in the Southern Hemisphere. In the Southern Hemisphere, Rigel is the first bright star of Orion visible as the constellation rises. Correspondingly, it is also the first star of Orion to set in most of the Northern Hemisphere. The star is a vertex of the "Winter Hexagon", an asterism that includes Aldebaran, Capella, Pollux, Procyon, and Sirius. Rigel is a prominent equatorial navigation star, being easily located and readily visible in all the world's oceans (the exception is the area north of the 82nd parallel north).
Rigel's spectral type is a defining point of the classification sequence for supergiants.[36][37] The overall spectrum is typical for a late B class star, with strong absorption lines of the hydrogen Balmer series as well as neutral helium lines and some of heavier elements such as oxygen, calcium, and magnesium.[38] The luminosity class for B8 stars is estimated from the strength and narrowness of the hydrogen spectral lines, and Rigel is assigned to the bright supergiant class Ia.[39] Variations in the spectrum have resulted in the assignment of different classes to Rigel, such as B8 Ia, B8 Iab, and B8 Iae.
As early as 1888, the heliocentric radial velocity of Rigel, as estimated from the Doppler shifts of its spectral lines, was seen to vary. This was confirmed and interpreted at the time as being due to a spectroscopic companion with a period of about 22 days. The radial velocity has since been measured to vary by about 10 km/s around a mean of 21.5 km/s.
In 1933, the Hα line in Rigel's spectrum was seen to be unusually weak and shifted 0.1 nm towards shorter wavelengths, while there was a narrow emission spike about 1.5 nm to the long wavelength side of the main absorption line. This is now known as a P Cygni profile after a star that shows this feature strongly in its spectrum. It is associated with mass loss where there is simultaneously emission from a dense wind close to the star and absorption from circumstellar material expanding away from the star.
The unusual Hα line profile is observed to vary unpredictably. It is a normal absorption line around a third of the time. About a quarter of the time, it is a double-peaked line, that is, an absorption line with an emission core or an emission line with an absorption core. About a quarter of the time it has a P Cygni profile; most of the rest of the time, the line has an inverse P Cygni profile, where the emission component is on the short wavelength side of the line. Rarely, there is a pure emission Hα line. The line profile changes are interpreted as variations in the quantity and velocity of material being expelled from the star. Occasional very high-velocity outflows have been inferred, and, more rarely, infalling material. The overall picture is one of large looping structures arising from the photosphere and driven by magnetic fields.
Rigel has been known to vary in brightness since at least 1930. The small amplitude of Rigel's brightness variation requires photoelectric or CCD photometry to be reliably detected. This brightness variation has no obvious period. Observations over 18 nights in 1984 showed variations at red, blue, and yellow wavelengths of up to 0.13 magnitudes on timescales of a few hours to several days, but again no clear period. Rigel's color index varies slightly, but this is not significantly correlated with its brightness variations.
From analysis of Hipparcos satellite photometry, Rigel is identified as belonging to the Alpha Cygni class of variable stars, defined as "non-radially pulsating supergiants of the Bep–AepIa spectral types". In those spectral types, the 'e' indicates that it displays emission lines in its spectrum, while the 'p' means it has an unspecified spectral peculiarity. Alpha Cygni type variables are generally considered to be irregular or have quasi-periods. Rigel was added to the General Catalogue of Variable Stars in the 74th name-list of variable stars on the basis of the Hipparcos photometry, which showed variations with a photographic amplitude of 0.039 magnitudes and a possible period of 2.075 days. Rigel was observed with the Canadian MOST satellite for nearly 28 days in 2009. Milli-magnitude variations were observed, and gradual changes in flux suggest the presence of long-period pulsation modes.
From observations of the variable Hα spectral line, Rigel's mass-loss rate due to stellar wind is estimated be (1.5±0.4)×10−7 solar masses per year (M☉/yr)—about ten million times more than the mass-loss rate from the Sun.[52] More detailed optical and K band infrared spectroscopic observations, together with VLTI interferometry, were taken from 2006 to 2010. Analysis of the Hα and Hγ line profiles, and measurement of the regions producing the lines, show that Rigel's stellar wind varies greatly in structure and strength. Loop and arm structures were also detected within the wind. Calculations of mass loss from the Hγ line give (9.4±0.9)×10−7 M☉/yr in 2006-7 and (7.6±1.1)×10−7 M☉/yr in 2009–10. Calculations using the Hα line give lower results, around 1.5×10−7 M☉/yr. The terminal wind velocity is 300 km/s. It is estimated that Rigel has lost about three solar masses (M☉) since beginning life as a star of 24±3 M☉ seven to nine million years ago.
Rigel's distance from the Sun is somewhat uncertain, different estimates being obtained by different methods. Old estimates placed it 166 parsecs (or 541 light years) away from the Sun. The 2007 Hipparcos new reduction of Rigel's parallax is 3.78±0.34 mas, giving a distance of 863 light-years (265 parsecs) with a margin of error of about 9%. Rigel B, usually considered to be physically associated with Rigel and at the same distance, has a Gaia Data Release 3 parallax of 3.2352±0.0553 mas, suggesting a distance around 1,000 light-years (310 parsecs). However, the measurements for this object may be unreliable.
Indirect distance estimation methods have also been employed. For example, Rigel is believed to be in a region of nebulosity, its radiation illuminating several nearby clouds. Most notable of these is the 5°-long IC 2118 (Witch Head Nebula), located at an angular separation of 2.5° from the star, or a projected distance of 39 light-years (12 parsecs) away. From measures of other nebula-embedded stars, IC 2118's distance is estimated to be 949 ± 7 light-years (291 ± 2 parsecs).
Rigel is an outlying member of the Orion OB1 association, which is located at a distance of up to 1,600 light-years (500 parsecs) from Earth. It is a member of the loosely defined Taurus-Orion R1 Association, somewhat closer at 1,200 light-years (360 parsecs). Rigel is thought to be considerably closer than most of the members of Orion OB1 and the Orion Nebula. Betelgeuse and Saiph lie at a similar distance to Rigel, although Betelgeuse is a runaway star with a complex history and might have originally formed in the main body of the association.
The star system of which Rigel is a part has at least four components. Rigel (sometimes called Rigel A to distinguish from the other components) has a visual companion, which is likely a close triple-star system. A fainter star at a wider separation might be a fifth component of the Rigel system.
William Herschel discovered Rigel to be a visual double star on 1 October 1781, cataloguing it as star 33 in the "second class of double stars" in his Catalogue of Double Stars, usually abbreviated to H II 33, or as H 2 33 in the Washington Double Star Catalogue.
Friedrich Georg Wilhelm von Struve first measured the relative position of the companion in 1822, cataloguing the visual pair as Σ 668. The secondary star is often referred to as Rigel B or β Orionis B. The angular separation of Rigel B from Rigel A is 9.5 arc seconds to its south along position angle 204°. Although not particularly faint at visual magnitude 6.7, the overall difference in brightness from Rigel A (about 6.6 magnitudes or 440 times fainter) makes it a challenging target for telescope apertures smaller than 15 cm (6 in).
At Rigel's estimated distance, Rigel B's projected separation from Rigel A is over 2,200 astronomical units (AU). Since its discovery, there has been no sign of orbital motion, although both stars share a similar common proper motion. The pair would have an estimated orbital period of 24,000 years. Gaia Data Release 2 (DR2) contains a somewhat unreliable parallax for Rigel B, placing it at about 1,100 light-years (340 parsecs), further away than the Hipparcos distance for Rigel, but similar to the Taurus-Orion R1 association. There is no parallax for Rigel in Gaia DR2. The Gaia DR2 proper motions for Rigel B and the Hipparcos proper motions for Rigel are both small, although not quite the same.
In 1871, Sherburne Wesley Burnham suspected Rigel B to be a binary system, and in 1878, he resolved it into two components. This visual companion is designated as component C (Rigel C), with a measured separation from component B that varies from less than 0.1″ to around 0.3″. In 2009, speckle interferometry showed the two almost identical components separated by 0.124″, with visual magnitudes of 7.5 and 7.6, respectively. Their estimated orbital period is 63 years. Burnham listed the Rigel multiple system as β 555 in his double star catalog or BU 555 in modern use.
Component B is a double-lined spectroscopic binary system, which shows two sets of spectral lines combined within its single stellar spectrum. Periodic changes observed in relative positions of these lines indicate an orbital period of 9.86 days. The two spectroscopic components Rigel Ba and Rigel Bb cannot be resolved in optical telescopes but are known to both be hot stars of spectral type around B9. This spectroscopic binary, together with the close visual component Rigel C, is likely a physical triple-star system, although Rigel C cannot be detected in the spectrum, which is inconsistent with its observed brightness.
In 1878, Burnham found another possibly associated star of approximately 13th magnitude. He listed it as component D of β 555, although it is unclear whether it is physically related or a coincidental alignment. Its 2017 separation from Rigel was 44.5″, almost due north at a position angle of 1°.[8] Gaia DR2 finds it to be a 12th magnitude sunlike star at approximately the same distance as Rigel. Likely a K-type main-sequence star, this star would have an orbital period of around 250,000 years, if it is part of the Rigel system.
A spectroscopic companion to Rigel was reported on the basis of radial velocity variations, and its orbit was even calculated, but subsequent work suggests the star does not exist and that observed pulsations are intrinsic to Rigel itself.
Rigel is a blue supergiant that has exhausted the hydrogen fuel in its core, expanded and cooled as it moved away from the main sequence across the upper part of the Hertzsprung–Russell diagram. When it was on the main sequence, its effective temperature would have been around 30,000 K. Rigel's complex variability at visual wavelengths is caused by stellar pulsations similar to those of Deneb. Further observations of radial velocity variations indicate that it simultaneously oscillates in at least 19 non-radial modes with periods ranging from about 1.2 to 74 days.
Estimation of many physical characteristics of blue supergiant stars, including Rigel, is challenging due to their rarity and uncertainty about how far they are from the Sun. As such, their characteristics are mainly estimated from theoretical stellar evolution models. Its effective temperature can be estimated from the spectral type and color to be around 12,100 K. A mass of 21±3 M☉ at an age of 8±1 million years has been estimated by comparing evolutionary tracks, while atmospheric modeling from the spectrum gives a mass of 24±8 M☉.
Although Rigel is often considered the most luminous star within 1,000 light-years of the Sun, its energy output is poorly known. Using the Hipparcos distance of 860 light-years (264 parsecs), the estimated relative luminosity for Rigel is about 120,000 times that of the Sun (L☉), but another recently published distance of 1,170 ± 130 light-years (360 ± 40 parsecs) suggests an even higher luminosity of 219,000 L☉. Other calculations based on theoretical stellar evolutionary models of Rigel's atmosphere give luminosities anywhere between 83,000 L☉ and 363,000 L☉, while summing the spectral energy distribution from historical photometry with the Hipparcos distance suggests a luminosity as low as 61,515±11,486 L☉.
A 2018 study using the Navy Precision Optical Interferometer measured the angular diameter as 2.526 mas. After correcting for limb darkening, the angular diameter is found to be 2.606±0.009 mas, yielding a radius of 74.1+6.1−7.3 R☉. An older measurement of the angular diameter gives 2.75±0.01 mas, equivalent to a radius of 78.9 R☉ at 264 pc. These radii are calculated assuming the Hipparcos distance of 264 pc; adopting a distance of 360 pc leads to a significantly larger size. Older distance estimates were mostly far lower than modern estimates, leading to lower radius estimates; a 1922 estimate by John Stanley Plaskett gave Rigel a diameter of 25 million miles, or approximately 28.9 R☉, smaller than its neighbor Aldebaran.
Due to their closeness to each other and ambiguity of the spectrum, little is known about the intrinsic properties of the members of the Rigel BC triple system. All three stars seem to be near equally hot B-type main-sequence stars that are three to four times as massive as the Sun.
Stellar evolution models suggest the pulsations of Rigel are powered by nuclear reactions in a hydrogen-burning shell that is at least partially non-convective. These pulsations are stronger and more numerous in stars that have evolved through a red supergiant phase and then increased in temperature to again become a blue supergiant. This is due to the decreased mass and increased levels of fusion products at the surface of the star.
Rigel is likely to be fusing helium in its core. Due to strong convection of helium produced in the core while Rigel was on the main sequence and in the hydrogen-burning shell since it became a supergiant, the fraction of helium at the surface has increased from 26.6% when the star formed to 32% now. The surface abundances of carbon, nitrogen, and oxygen seen in the spectrum are compatible with a post-red supergiant star only if its internal convection zones are modeled using non-homogeneous chemical conditions known as the Ledoux Criteria.
Rigel is expected to eventually end its stellar life as a type II supernova. It is one of the closest known potential supernova progenitors to Earth, and would be expected to have a maximum apparent magnitude of around −11 (about the same brightness as a quarter Moon or around 300 times brighter than Venus ever gets). The supernova would leave behind either a black hole or a neutron star.