Family Quad Bike Dubai Lahbab Area

Polaris

Location of Polaris (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Ursa Minor
Pronunciation	/pəˈlɛərɪs, -ˈlær-/; UK: /pəˈlɑːrɪs/[1]
α UMi A
Right ascension	02h 31m 49.09s[2]
Declination	+89° 15′ 50.8″[2]
Apparent magnitude (V)	1.98[3] (1.86 – 2.13)[4]
α UMi B
Right ascension	02h 30m 41.63s[5]
Declination	+89° 15′ 38.1″[5]
Apparent magnitude (V)	8.7[3]
Characteristics
α UMi A
Spectral type	F7Ib + F6V[6]
U−B color index	0.38[3]
B−V color index	0.60[3]
Variable type	Classical Cepheid[4]
α UMi B
Spectral type	F3V[3]
U−B color index	0.01[7]
B−V color index	0.42[7]
Variable type	suspected[4]
Astrometry
Radial velocity (Rv)	−17[8] km/s
Proper motion (μ)	RA: 44.48±0.11[2] mas/yr Dec.: −11.85±0.13[2] mas/yr
Parallax (π)	7.54±0.11 mas[2]
Distance	446.5±1.1 ly (136.90±0.34 pc)[9]
Absolute magnitude (MV)	−3.6 (α UMi Aa)[3] 3.6 (α UMi Ab)[3] 3.1 (α UMi B)[3]
Position (relative to α UMi Aa)
Component	α UMi Ab
Epoch of observation	2005.5880
Angular distance	0.172″
Position angle	231.4°
Position (relative to α UMi Aa)
Component	α UMi B
Epoch of observation	2005.5880
Angular distance	18.217″
Position angle	230.540°
Orbit[9]
Primary	α UMi Aa
Companion	α UMi Ab
Period (P)	29.416±0.028 yr
Semi-major axis (a)	0.12955±0.00205" (≥2.90±0.03 AU[10])
Eccentricity (e)	0.6354±0.0066
Inclination (i)	127.57±1.22°
Longitude of the node (Ω)	201.28±1.18°
Periastron epoch (T)	2016.831±0.044
Argument of periastron (ω) (primary)	304.54±0.84°
Semi-amplitude (K1) (primary)	3.762±0.025 km/s
Details
α UMi Aa
Mass	5.13±0.28[9] M☉
Radius	46.27±0.42[9] R☉
Luminosity (bolometric)	1,260[11] L☉
Surface gravity (log g)	2.2[12] cgs
Temperature	6015[7] K
Metallicity	112% solar[13]
Rotation	119 days[6]
Rotational velocity (v sin i)	14[6] km/s
Age	45 - 67?[14][15] Myr
α UMi Ab
Mass	1.316[9] M☉
Radius	1.04[3] R☉
Luminosity (bolometric)	3[3] L☉
Age	>500?[15] Myr
α UMi B
Mass	1.39[3] M☉
Radius	1.38[7] R☉
Luminosity (bolometric)	3.9[7] L☉
Surface gravity (log g)	4.3[7] cgs
Temperature	6900[7] K
Rotational velocity (v sin i)	110[7] km/s
Age	1.5?[14][15] Gyr
Other designations
Polaris, North Star, Cynosura, Alpha UMi, α UMi, ADS 1477, CCDM J02319+8915
α UMi A: 1 Ursae Minoris, BD+88°8, FK5 907, GC 2243, HD 8890, HIP 11767, HR 424, SAO 308
α UMi B: NSV 631, BD+88°7, GC 2226, SAO 305
Database references
SIMBAD	α UMi A
	α UMi B

Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris (Latinized to Alpha Ursae Minoris) and is commonly called the North Star. With an apparent magnitude that fluctuates around 1.98,^[3] it is the brightest star in the constellation and is readily visible to the naked eye at night.^[16] The position of the star lies less than 1° away from the north celestial pole, making it the current northern pole star. The stable position of the star in the Northern Sky makes it useful for navigation.^[17]

Although appearing to the naked eye as a single point of light, Polaris is a triple star system, composed of the primary, a yellow supergiant designated Polaris Aa, in orbit with a smaller companion, Polaris Ab; the pair is almost certainly^[14] in a wider orbit with Polaris B. The outer companion B was discovered in August 1779 by William Herschel, with the inner Aa/Ab pair only confirmed in the early 20th century.

As the closest Cepheid variable, Polaris Aa's distance is a foundational part of the cosmic distance ladder. The revised Hipparcos stellar parallax gives a distance to Polaris A of about 432 light-years (ly) (133 parsecs (pc)), while the successor mission Gaia gives a distance of 446.5 ly (136.9 pc) for Polaris B^[9][a].

Polaris Aa is an evolved yellow supergiant of spectral type F7Ib with 5.4 solar masses (M_☉). It is the first classical Cepheid to have a mass determined from its orbit. The two smaller companions are Polaris B, a 1.39 M_☉ F3 main-sequence star orbiting at a distance of 2,400 astronomical units (AU),^[18] and Polaris Ab (or P), a very close F6 main-sequence star with a mass of 1.26 M_☉.^[3] In January 2006, NASA released images, from the Hubble telescope, that showed the three members of the Polaris ternary system.^[19][20]

Polaris B can be resolved with a modest telescope. William Herschel discovered the star in August 1779 using a reflecting telescope of his own, one of the best telescopes of the time.^[21]

The variable radial velocity of Polaris A was reported by W. W. Campbell in 1899, which suggested this star is a binary system.^[22] Since Polaris A is a known cepheid variable, J. H. Moore in 1927 demonstrated that the changes in velocity along the line of sight were due to a combination of the four-day pulsation period combined with a much longer orbital period and a large eccentricity of around 0.6.^[23] Moore published preliminary orbital elements of the system in 1929, giving an orbital period of about 29.7 years with an eccentricity of 0.63. This period was confirmed by proper motion studies performed by B. P. Gerasimovič in 1939.^[24]

As part of her doctoral thesis, in 1955 E. Roemer used radial velocity data to derive an orbital period of 30.46 y for the Polaris A system, with an eccentricity of 0.64.^[25] K. W. Kamper in 1996 produced refined elements with a period of 29.59±0.02 years and an eccentricity of 0.608±0.005.^[26] In 2019, a study by R. I. Anderson gave a period of 29.32±0.11 years with an eccentricity of 0.620±0.008.^[10]

There were once thought to be two more widely separated components—Polaris C and Polaris D—but these have been shown not to be physically associated with the Polaris system.^[18][27]

Polaris Aa, the supergiant primary component, is a low-amplitude population I classical Cepheid variable, although it was once thought to be a type II Cepheid due to its high galactic latitude. Cepheids constitute an important standard candle for determining distance, so Polaris, as the closest such star,^[10] is heavily studied. The variability of Polaris had been suspected since 1852; this variation was confirmed by Ejnar Hertzsprung in 1911.^[29]

The range of brightness of Polaris is given as 1.86–2.13,^[4] but the amplitude has changed since discovery. Prior to 1963, the amplitude was over 0.1 magnitude and was very gradually decreasing. After 1966, it very rapidly decreased until it was less than 0.05 magnitude; since then, it has erratically varied near that range. It has been reported that the amplitude is now increasing again, a reversal not seen in any other Cepheid.^[6]

The period, roughly 4 days, has also changed over time. It has steadily increased by around 4.5 seconds per year except for a hiatus in 1963–1965. This was originally thought to be due to secular redward evolution across the Cepheid instability strip, but it may be due to interference between the primary and the first-overtone pulsation modes.^[20][30][31] Authors disagree on whether Polaris is a fundamental or first-overtone pulsator and on whether it is crossing the instability strip for the first time or not.^[11][31][32]

The temperature of Polaris varies by only a small amount during its pulsations, but the amplitude of this variation is variable and unpredictable. The erratic changes of temperature and the amplitude of temperature changes during each cycle, from less than 50 K to at least 170 K, may be related to the orbit with Polaris Ab.^[12]

Research reported in Science suggests that Polaris is 2.5 times brighter today than when Ptolemy observed it, changing from third to second magnitude.^[33] Astronomer Edward Guinan considers this to be a remarkable change and is on record as saying that "if they are real, these changes are 100 times larger than [those] predicted by current theories of stellar evolution".

Torres 2023 published a broad historical compilation of radial velocity and photometric data. He concludes that the change in the Cepheid period has reversed and is now decreasing since roughly 2010. Torres notes that TESS data is of limited utility: as a survey telescope, TESS is optimized for dimmer stars than Polaris, so Polaris significantly over-saturates TESS's cameras. Determining an accurate total brightness for Polaris from TESS is extremely difficult, although it remains suitable for timing the period.^[34]

Furthermore, apparent irregularities in Polaris Aa's behavior may coincide with the periastron passage of Ab, although imprecision in the data prevents a definitive conclusion.^[34] At the Gaia distance, the Aa-Ab closest approach is 6.2 AU; the radius of the primary supergiant is 46 R_☉, meaning that the periastron separation is about 29 times its radius. This implies tidal forcing upon Aa's upper atmosphere by Ab. Such binary tidal forcing is known from heartbeat stars, where eccentric periastron approaches cause rich multimode pulsation akin to an electrocardiogram.

Szabados 1992 suggests that, among Cepheids, "phase slips" similar to what happened to Polaris in the mid 1960s are associated with binary systems.^[35]

In 2024, researchers led by Nancy Evans at the Harvard & Smithsonian published a study with fresh data on the inner binary using the interferometric CHARA Array. They improved the solution of the orbit: combining CHARA data with previous Hubble data, and in tandem with the Gaia distance of 446±1 light-years, they confirmed the Cepheid radius estimate of 46 R_☉ and re-determined its mass at 5.13±0.28 M_☉. The corresponding Polaris Ab mass is 1.316±0.028 M_☉. Polaris remains overluminous compared to the best Cepheid evolution models, something also seen in V1334 Cygni. Polaris's rapid period change and pulsation amplitude variations are still peculiar compared to other Cepheids, but may be related to the first-overtone pulsations.^[9]

Evans et al also tentatively succeeded in imaging features on the surface of Polaris Aa: large bright and dark patches appear in close-up images, changing over time. Follow up imaging campaigns are required to confirm this detection.^[9] Polaris's age is difficult to model; current best estimates find the Cepheid to be much younger than the two main sequence components, seemingly enough to exclude a common origin, which would be quite unlikely for a triple star system.^[14][15]

Torres 2023 and Evans et al 2024 both suggest that recent literature cautiously agree that Polaris is a first overtone pulsator.^[34][9]

Because Polaris lies nearly in a direct line with the Earth's rotational axis above the North Pole, it stands almost motionless in the sky, and all the stars of the northern sky appear to rotate around it. It thus provides a nearly fixed point from which to draw measurements for celestial navigation and for astrometry. The elevation of the star above the horizon gives the approximate latitude of the observer.^[16]

In 2018 Polaris was 0.66° (39.6 arcminutes) away from the pole of rotation (1.4 times the Moon disc) and so revolves around the pole in a small circle 1.3° in diameter. It will be closest to the pole (about 0.45 degree, or 27 arcminutes) soon after the year 2100.^[37] Because it is so close to the celestial north pole, its right ascension is changing rapidly due to the precession of Earth's axis, going from 2.5h in AD 2000 to 6h in AD 2100. Twice in each sidereal day Polaris's azimuth is true north; the rest of the time it is displaced eastward or westward, and the bearing must be corrected using tables or a rule of thumb. The best approximation^[36] is made using the leading edge of the "Big Dipper" asterism in the constellation Ursa Major. The leading edge (defined by the stars Dubhe and Merak) is referenced to a clock face, and the true azimuth of Polaris worked out for different latitudes.

The apparent motion of Polaris towards and, in the future, away from the celestial pole, is due to the precession of the equinoxes.^[38] The celestial pole will move away from α UMi after the 21st century, passing close by Gamma Cephei by about the 41st century, moving towards Deneb by about the 91st century.^{[citation needed]}

The celestial pole was close to Thuban around 2750 BCE,^[38] and during classical antiquity it was slightly closer to Kochab (β UMi) than to Polaris, although still about 10° from either star.^[39] It was about the same angular distance from β UMi as to α UMi by the end of late antiquity. The Greek navigator Pytheas in ca. 320 BC described the celestial pole as devoid of stars. However, as one of the brighter stars close to the celestial pole, Polaris was used for navigation at least from late antiquity, and described as ἀεί φανής (aei phanēs) "always visible" by Stobaeus (5th century), also termed Λύχνος (Lychnos) akin to a burner or lamp and would reasonably be described as stella polaris from about the High Middle Ages and onwards, both in Greek and Latin. On his first trans-Atlantic voyage in 1492, Christopher Columbus had to correct for the "circle described by the pole star about the pole".^[40] In Shakespeare's play Julius Caesar, written around 1599, Caesar describes himself as being "as constant as the northern star", although in Caesar's time there was no constant northern star. Despite its relative brightness, it is not, as is popularly believed, the brightest star in the sky.^[41]

Polaris was referenced in the classic Nathaniel Bowditch maritime navigation book American Practical Navigator (1802), where it is listed as one of the navigational stars.^[42]

The modern name Polaris^[43] is shortened from the Neo-Latin stella polaris ("polar star"), coined in the Renaissance when the star had approached the celestial pole to within a few degrees.^[44][45]

Gemma Frisius, writing in 1547, referred to it as stella illa quae polaris dicitur ("that star which is called 'polar'"), placing it 3° 8' from the celestial pole.^[44][45]

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)^[46] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Polaris for the star α Ursae Minoris Aa.^[47]

In antiquity, Polaris was not yet the closest naked-eye star to the celestial pole, and the entire constellation of Ursa Minor was used for navigation rather than any single star. Polaris moved close enough to the pole to be the closest naked-eye star, even though still at a distance of several degrees, in the early medieval period, and numerous names referring to this characteristic as polar star have been in use since the medieval period. In Old English, it was known as scip-steorra ("ship-star").^{[citation needed]}

In the "Old English rune poem", the T-rune is apparently associated with "a circumpolar constellation", or the planet Mars.^[48]

In the Hindu Puranas, it became personified under the name Dhruva ("immovable, fixed").^[49]

In the later medieval period, it became associated with the Marian title of Stella Maris "Star of the Sea" (so in Bartholomaeus Anglicus, c. 1270s),^[50] due to an earlier transcription error.^[51]

An older English name, attested since the 14th century, is lodestar "guiding star", cognate with the Old Norse leiðarstjarna, Middle High German leitsterne.^[52]

The ancient name of the constellation Ursa Minor, Cynosura (from the Greek κυνόσουρα "the dog's tail"),^[53] became associated with the pole star in particular by the early modern period. An explicit identification of Mary as stella maris with the polar star (Stella Polaris), as well as the use of Cynosura as a name of the star, is evident in the title Cynosura seu Mariana Stella Polaris (i.e. "Cynosure, or the Marian Polar Star"), a collection of Marian poetry published by Nicolaus Lucensis (Niccolo Barsotti de Lucca) in 1655. ^{[citation needed]}

Its name in traditional pre-Islamic Arab astronomy was al-Judayy الجدي ("the kid", in the sense of a juvenile goat ["le Chevreau"] in Description des Etoiles fixes),^[54] and that name was used in medieval Islamic astronomy as well.^[55][56] In those times, it was not yet as close to the north celestial pole as it is now, and used to rotate around the pole.^{[citation needed]}

It was invoked as a symbol of steadfastness in poetry, as "steadfast star" by Spenser. Shakespeare's sonnet 116 is an example of the symbolism of the north star as a guiding principle: "[Love] is the star to every wandering bark / Whose worth's unknown, although his height be taken."^[57]

In Julius Caesar, Shakespeare has Caesar explain his refusal to grant a pardon: "I am as constant as the northern star/Of whose true-fixed and resting quality/There is no fellow in the firmament./The skies are painted with unnumbered sparks,/They are all fire and every one doth shine,/But there's but one in all doth hold his place;/So in the world" (III, i, 65–71). Of course, Polaris will not "constantly" remain as the north star due to precession, but this is only noticeable over centuries.^{[citation needed]}

In Inuit astronomy, Polaris is known as Nuutuittuq (syllabics: ᓅᑐᐃᑦᑐᖅ).^[58]

In traditional Lakota star knowledge, Polaris is named "Wičháȟpi Owáŋžila". This translates to "The Star that Sits Still". This name comes from a Lakota story in which he married Tȟapȟúŋ Šá Wíŋ, "Red Cheeked Woman". However, she fell from the heavens, and in his grief Wičháȟpi Owáŋžila stared down from "waŋkátu" (the above land) forever.^[59]

The Plains Cree call the star in Nehiyawewin: acâhkos êkâ kâ-âhcît "the star that does not move" (syllabics: ᐊᒑᐦᑯᐢ ᐁᑳ ᑳ ᐋᐦᒌᐟ).^[60]

In Mi'kmawi'simk the star is named Tatapn.^[61]

In the ancient Finnish worldview, the North Star has also been called taivaannapa and naulatähti ("the nailstar") because it seems to be attached to the firmament or even to act as a fastener for the sky when other stars orbit it. Since the starry sky seemed to rotate around it, the firmament is thought of as a wheel, with the star as the pivot on its axis. The names derived from it were sky pin and world pin.^{[citation needed]}

Since Leavitt's discovery of the Cepheid variable period-luminosity relationship, and corresponding utility as a standard candle, the distance to Polaris has been highly sought-after by astronomers. It is the closest Cepheid to Earth, and thus key to calibrating the Cepheid standard candle; Cepheids form the base of the cosmic distance ladder by which to probe the cosmological nature of the universe.^[62]

Distance measurement techniques depend on whether or not components A and B are a physical pair, that is, gravitationally bound. If they are, then their estimated distance can be presumed to be equal.^[b] Gravitational binding of this pair is well supported by observations, and the presumption of common distance is widely adopted in historical and recent estimates.^{[64][65][66][26][67][62][14][9]}

For most of the 20th century, available observation technologies remained inadequate to precisely measure absolute parallax.^[68][62] Instead, the main technique was to use theoretical models of stellar evolution for both main sequence and giant stars, combined with spectroscopic and photometric data to estimate distances. Such modeling relies on theoretical assumptions and guesses, and contains much systematic error and statistical uncertainties in population data. Even by 2013, these techniques were still struggling to achieve even 10% precision in either main sequence^[69] or Cepheid^[14] modeling.

Further progress was thus limited until the advent of Hipparcos, the first instrument able to engage in all-sky absolute parallax astrometry.^[68] Its first data release was in 1997.

After the arrival of the Hipparcos data, the distance to Polaris and consequent analysis of its Cepheid variation was controversial. The Hipparcos distance for Polaris was broadly but not universally adopted.^[20] Immediately, the Hipparcos data for the nearest few hundred Cepheids appeared to clarify Cepheid models and to clear up then-tension in higher rungs of the distance ladder.^[70] However alternatives remained; particularly by Turner et al, who published several papers between 2004 and 2013.^[62]

In 2018, Bond et al^[14] used the Hubble Space Telescope to provide an alternate direct measurement of Polaris's parallax; they summarize the back-and-forth:

However, Turner et al. (2013, hereafter TKUG13)^[62] argue that the parallax of Polaris is considerably larger, 10.10 ± 0.20 mas (d = 99±2 pc). The evidence cited by TKUG13 for this “short” distance includes (1) a photometric parallax for Polaris B based on measured photometry, spectral classification, and main-sequence fitting; (2) a claim that there is a sparse cluster of A-, F-, and G-type stars within 3° of Polaris, with proper motions and radial velocities similar to that of the Cepheid, for which the Hipparcos parallaxes combined with main-sequence fitting give a distance of 99 pc; and (3) a determination of the absolute visual magnitude of Polaris based on line ratios in high-resolution spectra, calibrated against supergiants with well-established luminosities. [...]

[...]

In a critique of the TKUG13 paper, van Leeuwen (2013, hereafter L13)^[69] defended the Hipparcos parallax by presenting details of the solution, concluding that “the Hipparcos data cannot in any way support” the large parallax advocated by TKUG13. Using Hipparcos data, L13 also questioned the reality of the sparse cluster proposed by TKUG13, presenting evidence against it both from the color versus absolute-magnitude diagram for stars within 3° of Polaris, and their non-clustered distribution of proper motions. Lastly, L13 examined the absolute magnitudes of nearly 400 stars of spectral type F3 V in the Hipparcos catalog with parallax errors of less than 10%, and showed that the absolute magnitude of Polaris B would fall well within the observed MV distribution for F3 V stars, based on either the Hipparcos parallax of A or the larger parallax proposed by TKUG13. Thus, he concluded that the photometric parallax of B does not give a useful discriminant.

Bond et al go on to find a trigonometric parallax (independent of Hipparcos) that implies a distance further-still than the "long" Hipparcos distance, well outside the plausible range of the "short" distance estimates.

The next major step in high precision parallax measurements comes from Gaia, a space astrometry mission launched in 2013 and intended to measure stellar parallax to within 25 microarcseconds (μas).^[74] Although it was originally planned to limit Gaia's observations to stars fainter than magnitude 5.7, tests carried out during the commissioning phase indicated that Gaia could autonomously identify stars as bright as magnitude 3. When Gaia entered regular scientific operations in July 2014, it was configured to routinely process stars in the magnitude range 3 – 20.^[75] Beyond that limit, special procedures are used to download raw scanning data for the remaining 230 stars brighter than magnitude 3; methods to reduce and analyse these data are being developed; and it is expected that there will be "complete sky coverage at the bright end" with standard errors of "a few dozen μas".^[76]

Gaia DR2 does not include a parallax for Polaris A, but a distance inferred from Polaris B is 136.6±0.5 pc (445.5±1.7 ly),^[72] somewhat further than most previous estimates and (in principle) considerably more accurate. There are known to be considerable systematic uncertainties in DR2.^[77]

Gaia DR3 significantly improved both the statistical and systematic uncertainties, although the latter remain numerous and on the order of 10–60 μas^[63]; the new estimate is 136.9±0.3 pc (446.5±1.1 ly) using the baseline parallax zeropoint correction.^[5][9][h]

Gaia DR4 (expected December 2026) will further improve the statistical and systematic uncertainties in general, and the data pipelines for variable and multiple stars in particular.^[78] Multistar orbital solutions will become available, greatly aiding the study of Cepheids and Polaris, and in particular, may enable solving the outer AB orbit.^[9]

Polaris is depicted in the flag and coat of arms of the Canadian Inuit territory of Nunavut,^[79] the flag of the U.S. states of Alaska and Minnesota,^[80] and the flag of the U.S. city of Duluth, Minnesota.^[81][82]

• 
  Flag of Nunavut
• 
  Flag of Alaska
• 
  Flag of Minnesota
• 
  Flag of Duluth, Minnesota
• 
  Flag of Maine
• 
  Flag of Maine (1901–1909)
• 
  Flag of the Pan-American Exposition (1901)^[83]
• 
  Sledge flag used by Francis Leopold McClintock in the Arctic (1852–1854)^[84]

• 
  Coat of arms of Nunavut
• 
  Seal of Minnesota
• 
  Seal of Maine
• 
  Coat of arms of Utsjoki^{[citation needed]}

• The Chinese spy ship Beijixing is named after Polaris.
• USS Polaris is named after Polaris

• 
  Polaris is the brightest star in the constellation of Ursa Minor (upper right).
• 
  Big Dipper and Ursa Minor in relation to Polaris
• 
  A view of Polaris in a small telescope. Polaris B is separated by 18 arc seconds from the primary star, Polaris A.
• 
  Polaris, its surrounding integrated flux nebula, and NGC188^{[dubious – discuss]}

• Extraterrestrial sky (for the pole stars of other celestial bodies)
• List of nearest supergiants
• Polar alignment
• Sigma Octantis
• Polaris Flare
• Regiment of the North Pole

Wikimedia Commons has media related to Polaris.

Sports car racing series from 1966 to 1987

This article is about the motorsport cup. For the baseball league, see Canadian-American Association of Professional Baseball. For manufacturer of ATVs, see Can-Am motorcycles. For other uses, see Can-Am (disambiguation).

Can-Am

The logo of the Can-Am Challenge Cup
Category	Sports car racing
Country	United States, Canada
Folded	1987

The Canadian-American Challenge Cup, or Can-Am, was an SCCA/CASC sports car racing series from 1966 to 1974, and again from 1977 to 1987.

The Can-Am rules were deliberately simple and placed few limits on the entries. This led to a wide variety of unique car body designs and powerful engine installations. Notable among these were Jim Hall's Chaparrals and entries with over 1,000 horsepower.

History

[edit]

Can-Am started out as a race series for Group 7 sports racers with two races in Canada (Can) and four races in the United States of America (Am). The series was initially sponsored by Johnson Wax. The series was governed by rules called out under the FIA Group 7 category with unrestricted engine capacity and few other technical restrictions.

The Group 7 category was essentially a Formula Libre for sports cars; the regulations were minimal and permitted unlimited engine sizes (and allowed turbocharging and supercharging), virtually unrestricted aerodynamics, and were as close as any major international racing series ever got to have an "anything goes" policy. As long as the car had two seats, bodywork enclosing the wheels, and met basic safety standards, it was allowed. Group 7 had arisen as a category for non-homologated sports car "specials" in Europe and, for a while in the 1960s, Group 7 racing was popular in the United Kingdom as well as a class in hillclimb racing in Europe. Group 7 cars were designed more for short-distance sprints than for endurance racing. Some Group 7 cars were also built in Japan by Nissan and Toyota, but these did not compete outside their homeland (though some of the Can-Am competitors occasionally went over to race against them).

SCCA sports car racing was becoming more popular with European constructors and drivers, and the United States Road Racing Championship for large-capacity sports racers eventually gave rise to the Group 7 Can-Am series. There was good prize and appearance money and plenty of trade backing; the series was lucrative for its competitors but resulted, by its end, in truly outrageous cars with well over 1,000 horsepower (750 kW) (the Porsche team claimed 1,500 hp (1,100 kW) for its 917/30 in qualifying trim^[1]), wings, active downforce generation, very light weight and unheard of speeds. Similar Group 7 cars ran in the European Interserie series from 1970 on, but this was much lower-key than the Can-Am.

On-track, the series was initially dominated by Lola, followed by a period in which it became known as the "Bruce and Denny show", the works McLaren team dominated for five consecutive seasons (1967-1971) until the Porsche 917 was perfected and became almost unbeatable in 1972 and 1973. After Porsche's withdrawal, Shadow dominated the last season before Can-Am faded away to be replaced by Formula 5000. Racing was rarely close—one marque was usually dominant—but the noise and spectacle of the cars made the series highly popular.

The energy crisis and the increased cost of competing in Can-Am meant that the series folded after the relatively lackluster 1974 season; the single-seater Formula 5000 series became the leading road-racing series in North America and many of the Can-Am drivers and teams continued to race there. F5000's reign lasted for only two years, with a second generation of Can-Am following. This was a fundamentally different series based initially on converted F5000 cars with closed-wheel bodies. There was also a two-liter class based on Formula Two chassis. The second iteration of Can-Am faded away as IMSA and CART racing became more popular in the early 1980s but remained active until 1987.

Can-Am remains a well-remembered form of racing due to its popularity in the 1960s and early 1970s, the limited number of regulations allowing extremely fast and innovative cars and the lineup of talented drivers. Can-Am cars remain popular in historic racing today.

Notable drivers

[edit]

Notable drivers in the original Can-Am series included virtually every acclaimed driver of the late 1960s and early 1970s. Jim Hall, Mark Donohue, Mario Andretti, Parnelli Jones, George Follmer, Dan Gurney, Phil Hill, Denny Hulme, Jacky Ickx, Bruce McLaren, Jackie Oliver, Peter Revson, John Surtees, and Charlie Kemp all drove Can-Am cars competitively and were successful, winning races and championship titles. Al Holbert, Alan Jones and Al Unser Jr. are among the drivers who launched their careers in the revived Can-Am series.

Pioneering technology

[edit]

Can-Am was the birthplace and proving ground for what, at the time, was cutting-edge technology. Can-Am cars were among the first race cars to use sport wings, effective turbocharging, ground-effect aerodynamics, and aerospace materials like titanium. This led to the eventual downfall of the original series when costs got prohibitive. However during its height, Can-Am cars were at the forefront of racing technology and were frequently as fast as or even faster around laps of certain circuits than the contemporary Formula One cars. Noted constructors in the Can-Am series include McLaren, Chaparral, Lola, BRM, Shadow and Porsche.

Manufacturers

[edit]

McLaren

[edit]

McLaren cars were specially designed race cars. The Can-Am cars were developments of the sports cars which were introduced in 1964 for the North American sports car races. The team works car for 1964 was the M1. For 1965 the M1A prototype was the team car and bases for the Elva customer M1A cars. In late 1965 the M1b(mk2) was the factory car in 1966 with Bruce McLaren and Chris Amon as drivers. In 1967, specifically for the Can-Am series, the McLaren team introduced a new model, the M6A. The McLaren M6A also introduced what was to become the trademark orange color for the team. The McLaren team was considered very "multinational" for the times and consisted of team owner and leader Bruce McLaren, fellow New Zealander Chris Amon and another "kiwi", the 1967 Formula One world champion, Denny Hulme, team manager Teddy Mayer, mechanics Tyler Alexander, Gary Knutson, Lee Muir, George Bolthoff, Frank Zimmerman, Tom Anderson, Alan Anderson, David Dunlap, Leo Beattie, Donny Ray Everett, and Haig Alltounian (all from the US), Don Beresford, Alec Greaves, Vince Higgins, and Roger Bailey (UK), Tony Attard (Australia), Cary Taylor, Jimmy Stone, Chris Charles, Colin Beanland, Alan McCall, and Alistair Caldwell (NZ). The M6 series used a full aluminum monocoque design with no uncommon features but, for the times, there was an uncommon attention to detail in preparation by the team members. The M6 series of cars were powered by Chevy "mouse-motor" small-block V8s built by Al Bartz Engines in Van Nuys, California. They were models of reliability. This was followed in 1968 by the M8A, a new design based around the Chevy big-block V8 "rat motor" as a stressed member of the chassis. McLaren went "in house" with their engine shop in 1969. The M8B, M8C, M8D and M20C were developments of that aluminum monocoque chassis. McLaren so dominated the 1967-1971 seasons that Can-Am was often called the "Bruce and Denny show" after the drivers who very often finished first and second. There was even a one-two-three finish at the Michigan International Speedway on September 28, 1969: McLaren first, Hulme second, and Gurney third. Nine months later, Bruce McLaren lost his life, on June 2, 1970, at Goodwood when the rear bodywork of his prototype M8D detached during testing resulting in a completely uncontrollable car and a fatal high-speed crash. Team McLaren continued to succeed in Can-Am after Bruce's death with a number of other drivers, but the works Porsche effort with a turbocharged flat-12 engines and a high development budget meant that they could not keep up with the 917. Although private McLarens continued in the series, the works team withdrew to concentrate on Formula One (and USAC, for several years). Team McLaren went on to become a several time F1 champion and is still a part of that series.

Porsche

[edit]

The Porsche 908 spyder was used in Can-Am, but was underpowered (350 hp) and mainly used by underfunded teams. It did win the 1970 Road Atlanta race, when the more powerful cars fell out. The 917PA, a spyder version of the 917K Le Mans car, was raced, but its normally aspirated flat-12 was underpowered (530 hp). In 1971 the 917/10 was introduced. This was not turbocharged, but was lighter and had cleaner body work, and Jo Siffert managed to finish fourth in the championship.

For 1972 the 917/10K with a turbocharged 900 horsepower five-litre flat-12 was introduced. Prepared by Roger Penske and driven by Mark Donohue and George Follmer these cars won six of the nine races. In 1972 Porsche introduced an even more powerful car, the 917/30KL. Nicknamed the "Turbopanzer" this car was seen as a monster. With 1,100 or 1,580 horsepower (820/1161 kW in race or qualifying trim)^{[citation needed]} available from its 5.4 litre flat-12 and weighing 1,800 lb (816 kg) with better downforce this car won six of eight races in the 1973 championship.^[2] Porsche's dominance was such that engine rules were changed to try to reduce the lack of competition for one marque by enforcing a fuel-consumption rule for 1974. This kind of alteration of rules to promote equality is not unknown in other forms of American motorsport. The category that the car had been created for and competed in was discontinued and in 1975 Donohue drove this car to a closed-course world-speed record of 221 mph (average)(356 km/h) at the Talladega Superspeedway (then called the "Alabama International Motor Speedway"). It was capable of 240 mph (386 km/h) on the straights.^[3]

Chaparral

[edit]

Jim Hall's Chaparrals were very innovative, following his success in the United States Road Racing Championship (USRRC). The 2 series Chaparrals (built and engineered with a high degree of covert support from Chevrolet's research and development division) were leaders in the application of aerodynamics to race cars culminating with the introduction of the 2E in 1966, the first of the high wing race cars. The 2E was a defining design, and the 2G was a development of that basic design. The FIA banned movable aerodynamic devices and Chaparral responded with the 2H 1969. The 2H broke new ground, seeking to reduce drag but did not achieve much success. The 2J that followed was perhaps the ultimate example of what Group 7 rules could allow in a racing car. It was a twin-engined car, with the by-then usual big-block Chevrolet engine providing the driving force, and a tiny snowmobile engine powering a pair of fans at the back of the car. These fans, combined with the movable Lexan "skirts" around the bottom of the car created a vacuum underneath the car, effectively providing the same level of downforce as the huge wings of previous vehicles, without the drag. Although far too mechanically complex to survive in racing environments, the theory was sound, and would appear in Formula One a few years later in the BT46B "Fan Car" of 1978.

Lola

[edit]

The Lola T70, T160-165, T220, T260, and T310 were campaigned by the factory and various customers, and were primarily Chevy powered. The Lola T70 driven by John Surtees won the first Can-Am championship in 1966. Lola continued to experiment with new designs versus McLaren which refined the design each year. The 1971 Lola T260 had some success with Jackie Stewart taking two victories. In 1972 a radical new design, the Lola T310, made its appearance. The T310 was the longest and widest Can-Am car of the era versus the short stubby T260. The T310 was delivered late and suffered handling problems the entire year with its best finish a fourth at Watkins Glen.

Others

[edit]

While McLaren and Porsche dominated the series for most of its existence, other vehicles also appeared. Well-established European manufacturers like Lotus, CRD, in the form of their Merlyn Mk8 Chevrolet, Ferrari and BRM, appeared at various times with limited success, while March tried to get a share of the lucrative market in 1970–71, but could not establish themselves. Ford also flitted across the scene with a number of unsuccessful cars based on the GT40 and its successors. American specialist marques like McKee, Genie and Caldwell competed, alongside exotica like the astonishing four-engined Macs-It special.

British-born mechanic and engineer Peter Bryant designed the Ti22 (occasionally known as the Autocoast after one of the team's major backers) as an American-built challenger to the British McLarens and Lolas. The car made extensive use of titanium in its chassis and suspension, and Bryant experimented with aerodynamics and with early use of carbon-fibre to reduce weight. Although the car was quick it did not achieve consistent success; problems with the team's funding saw Bryant move on to Don Nichols' UOP-sponsored Shadow team. The Shadow marque had made its debut with an astonishing car with tiny wheels and radiators mounted on top of the rear wing designed by Trevor Harris; this was unsuccessful, and more conventional cars designed by Bryant replaced them; Bryant was sidelined when Shadow moved into Formula One but after his departure, turbocharged Shadows came to dominate as Porsche and McLaren faded from the scene.

Decline and revivals

[edit]

The last year for the original Can-Am championship was 1974. Spiraling costs, a recession in North America following the oil crisis, and dwindling support and interest led to the series being canceled and the last scheduled race of the 1974 season not being run.^[4]

The Can-Am name still held enough drawing power to lead SCCA to introduce a revised Can-Am series in 1977 based on a closed-wheel version of the rules of the recently canceled Formula A/5000 series. This grew steadily in status, particularly during the USAC/CART wars of the late 70s and early 80s, and attracted some top road-racing teams and drivers and a range of vehicles including specials based on rebodied single seaters (particularly Lola F5000s) and also bespoke cars from constructors like March as well as smaller manufacturers. To broaden the appeal of the series a 2L class was introduced for the last several years—cars often being derived from F2/Formula Atlantic. The series peaked in the early 80s but as the CART Indycar series and IMSA's GTP championship grew in stature it faded. In 1987 the series changed as Indycars started to become a source of cars. The SCCA took away the Can-Am name but the series continued as the Can-Am Teams Thunder Cars Championship. After a single year the teams took the sports bodies off and evolved into American Indycar Series.

In 1991, after 18 months of development, a Shelby Can-Am series was created using a production line of Sports bodied cars designed by Carroll Shelby powered by a 3.3 litre Dodge V6. The series ran for five years before it was dropped by the SCCA. A large number of cars were relocated to South Africa and ran from 2000 onwards.

The name was once again revived in 1998, when the United States Road Racing Championship broke away from IMSA. Their top prototype class was named Can-Am, but the series would fold before the end of 1999 before being replaced by the Grand American Road Racing Championship. The Can-Am name would not be retained in the new series.

Circuits

[edit]

Year	Driver	Team	Car
1966	John Surtees	Team Surtees	Lola T70-Chevrolet
1967	Bruce McLaren	Bruce McLaren Motor Racing	McLaren M6A-Chevrolet
1968	Denny Hulme	Bruce McLaren Motor Racing	McLaren M8A-Chevrolet
1969	Bruce McLaren	Bruce McLaren Motor Racing	McLaren M8B-Chevrolet
1970	Denny Hulme	Bruce McLaren Motor Racing	McLaren M8D-Chevrolet
1971	Peter Revson	Bruce McLaren Motor Racing	McLaren M8F-Chevrolet
1972	George Follmer	Penske Racing	Porsche 917/10
1973	Mark Donohue	Penske Racing	Porsche 917/30 TC
1974	Jackie Oliver	Shadow Racing Cars	Shadow DN4A-Chevrolet
1975–1976	No series
1977	Patrick Tambay	Haas-Hall Racing	Lola T333CS-Chevrolet
1978	Alan Jones	Haas-Hall Racing	Lola T333CS-Chevrolet
1979	Jacky Ickx	Carl Haas Racing	Lola T333CS-Chevrolet
1980	Patrick Tambay	Carl Haas Racing	Lola T530-Chevrolet
1981	Geoff Brabham	Team VDS	Lola T530-Chevrolet / VDS 001-Chevrolet
1982	Al Unser Jr.	Galles Racing	Frissbee GR3-Chevrolet
1983	Jacques Villeneuve Sr.	Canadian Tire	Frissbee GR3-Chevrolet
1984	Michael Roe	Norwood/Walker	VDS 002-Chevrolet / VDS 004-Chevrolet
1985	Rick Miaskiewicz	Mosquito Autosport	Frissbee GR3-Chevrolet
1986	Horst Kroll	Kroll Racing	Frissbee KR3-Chevrolet
1987	Bill Tempero	Texas American Racing Team	March 85C-Chevrolet

Year	Driver	Team	Car
1979	Tim Evans	Diversified Engineering Services	Lola T290-Ford
1980	Gary Gove	Pete Lovely VW	Ralt RT2-Hart
1981	Jim Trueman	TrueSports	Ralt RT2-Hart
1982	Bertil Roos	Elite Racing	Marquey CA82-Hart
1983	Bertil Roos	Roos Racing School	Scandia B3-Hart
1984	Kim Campbell	Tom Mitchell Racing	March 832-BMW
1985	Lou Sell	Sell Racing	March 832-BMW

• Can-Am, Pete Lyons, Motorbooks International
• Can-Am Races 1966–1969, Brooklands Books
• Can-Am Races 1970–1974, Brooklands Books
• Can-Am Racing Cars 1966–1974, Brooklands Books
• Can-Am Challenger, Peter Bryant, David Bull

Wikimedia Commons has media related to Can-Am (autosport).

• CanAm History site Archived 2005-08-31 at the Wayback Machine
• Can-Am History, by Michael Stucker
• Bruce McLaren Trust Official site
• Can-Am Results 1966-1986
• CanamCircus by Stéphane Lebiez
• Historic Can Am
• The History of the Canadian - American Challenge Cup