The First Known Variable Stars

Although there were occasional reports of new or guest stars in all cultures through the ages, medeval western astronomers looked at the "fixed" stars as eternal and invariable entities. This view was blown up in a dramatic show by Tycho's supernova ("Stella Nova", "New Star") in 1572. Soon after, some more variable stars were discovered, including the first periodic one, Mira (the periodicity of which was only discovered considerably later in 1638, by Holwarda; up to this time the four known variables had all been classified as "Stellae Novae", although none of them was actually a nova). However, the discovery rate of variables continued to stay on low level. In 1715, Edmond Halley published a list containing all 6 variables known at that time, and in 1781-2, when William Herschel discovered Uranus and published a catalog of 269 double stars, and Charles Messier published his catalog of 103 nebulae and star clusters, still only 8 variables were known, 4 of them periodic, all of Mira type (we have to discount the Cas A supernova in this counting because it had not been realized as variable or nova by that time).

The research of variables became a more serious science not before 1844, when F.W. Argelander called for their observation, and published a list of those variables then known (basically what we have in our table below).

According to G.D. Roth, the number of known variable stars has developed as follows: 12 by 1786, 18 by 1844, 175 by 1890, 393 by 1896, 4,000 by 1912, 22,650 by 1970, and 28,450 by 1983. As Hoffmeister states, of the 18 variables "known" in 1844, a list which had been published by F.W. Argelander, two (Alpha Cassiopeiae and Alpha Hydrae) are actually not variable, while Argelander had missed R Cancri (also). The most reliable reference, however, is probably Isles, who has researched at least two variables (i Bootis B and Epsilon Aurigae) which had been neglected by the other references.

Here is an attempt to list the earliest known variables (based on Isles, Hoffmeister and Strohmeier; note that Roth's numbers can apparently not be verified from this list); we hope to be rather complete for the time before 1844. We want to give basic data, images (where available) and links for each of these variable stars.

  • Early Variable Star Discoverers
  • List of all images
    Name                        Con  Type       Year Discoverer
    
    SN 1572 Cas SN 1572 W. Schuler, Tycho Brahe Mira, Omicron Ceti Cet Mira 1596 David Fabricius P Cygni, Nova 1600 Cygni Cyg S Dor 1600 Willem Janszoom Blaeu SN 1604 Oph SN 1604 Brunowsky, Joh. Kepler Algol, Beta Persei Per Algol 1669 Geminiano Montanari Nova Vulpeculae 1670, CK Vul Nova 1670 Dom Anthelme SN 1680 ? 1667 ? (Cas A) Cas SN 1680 John Flamsteed ? 1667 ? Chi Cygni Cyg Mira 1687 Gottfried Kirch R Hydrae Hya Mira 1704 Giacomo Filippo Maraldi R Leonis Leo Mira 1782 J.A. Koch Nova 1783 Sagittae, WY Sge Sge Nova 1783 D'Agelet Eta Aquilae Aql Delta Cep 1784 Edward Pigott Sheliak, Beta Lyrae Lyr Beta Lyr 1784 John Goodricke Delta Cephei Cep Delta Cep 1784 John Goodricke i Bootis B Boo W UMa 1785 William Herschel Ras Algheti, Alpha Herculis Her SR c 1795 William Herschel R Coronae Borealis CrB R CrB 1795 Edward Pigott R Scuti Sct RV Tau a 1795 Edward Pigott R Virginis Vir Mira 1809 Harding R Aquarii Aqr Mira 1810 Harding Epsilon Aurigae Aur Algol 1821 Fritsch R Serpentis Ser Mira 1826 Harding Eta Carinae Car S Dor 1827 Burchell, discovered 1677 Edmond Halley S Serpentis Ser Mira 1828 Harding R Cancri Cnc Mira 1829 Schwerd Betelgeuse, Alpha Orionis Ori SR c 1836 John Herschel
    Note: The supernovae of 1572 and 1604 were almost simultaneously noted by various observers. While Strohmeier lists Eta Carinae as being discovered, as variable, by Halley in 1677, Isles credits this discovery to Burchell, 1827. Isles reports that Goodricke and Pigott were amateur astronomers and neighbors, working together in the field of variable star research; Goodricke died from pneumonia he caught probably when observing Delta Cephei in 1786.

    Of the 26 variables listed here, 18 are showing periodic (or quasi-periodic) variability (4 eclipsing and 14 pulsating variables), while 8 are of eruptive type. The stars are representatives of the following types:

    Astronomical data of these variables

    Most of the data are from the Brightest Stars in the Sky collection at the MAA, supplemented by data from the Sky Catalogue 2000.0.
    Name                Con  RA (2000)  Dec(2000)  Type  max  min   Period    Spectr
    
    SN 1572 B Cas 00:25.3 +64:09 SN -4 Mira Omicron Cet 02:19:20.7 -02:58:39 Mira 2.0 10.1 331.96 M7IIIe P Cyg 20:17:47.1 +38:01:59 SDor 3.0 6.0 B2pe SN 1604 V 843 Oph 17:30.6 -21:29 SN -3 SN 1680?67? 3 Cas 23:23.4 +58:50 SN 6? Algol Beta Per 03:08:10.1 +40:57:21 EA 2.12 3.40 2.867 B8V+G5IV+Am Nova 1670 CK Vul 19:47.6 +27:19 Nova 2.7 Chi Cyg 19:50:33.8 +32:54:51 Mira 3.3 14.2 406.93 S6.2-10.4e R Hya 13:29:42.7 -23:16:52 Mira 3 11 389.61 M7IIIe R Leo 09:47:33.4 +11:25:43 Mira 4.4 11.3 312.43 M8IIIe Nova 1783 WY Sge 19:32.7 +17:45 Nova 5.4 19.5 Eta Aql 19:52:28.3 +01:00:20 DCep 3.48 4.39 7.177 F6Ibv Sheliak Beta Lyr 18:50:04.7 +33:21:46 EB 3.34 4.34 12.936 B7Ve+A8p Delta Cep 22:29:10.2 +58:24:55 DCep 3.48 4.37 5.366 F5Ib-G2Ib i Boo B Boo 15:03.8 +47:39 EW 6.5 7.1 0.268 G2V+G2V Ras Algethi Alpha Her 17:14:38.8 +14:23:25 SR c 3.1 3.9 mult M5Ib-II R CrB 15:48:34.3 +28:09:24 RCrB 5.85 14.8 G0Iep R Sct 18:47:28.9 -05:42:18 RV a 4.45 8.20 140.05 K0Ibpv R Vir 12:38:29.9 +06:59:18 Mira 6.0 12.1 145.64 M4.5IIIe R Aqr 23:43:49.4 -15:17:04 Mira 5.8 12.4 386.96 M7IIIpev Epsilon Aur 05:02.0 +43:49 EA 2.92 3.83 9892 A8Ie-F2Iaep R Ser 15:50:41.6 +15:08:00 Mira 5.16 14.4 356.41 M7IIIe Eta Car 10:45:03.6 -59:41:03 SDor -0.8 7.9 Pec S Ser 15:21.7 +14:19 Mira 7.0 14.1 368.59 M5-6e R Cnc 08:16:33.9 +11:43:35 Mira 6.07 11.8 361.60 M7IIIe Betelgeuse Alpha Ori 05:55:10.3 +07:24:25 SR c 0.40 1.3 ~2070: M1-2Ia-Iab

    Key:

    Name
    Common name and/or Bayer or variable star designation
    Con
    Constellation
    RA (2000), Dec (2000)
    Right Ascension and Declination for epoch 2000.0
    Type
    Variable star type: Cataclysmic: SN = supernova, Nova, SDor/S Dor = S Doradus (Hubble-Sandage Variables); Pulsating: Mira, DCep/Delta Cep = Delta Cephei variables, SR c = semi-regular supergiants, RV a = RV Tauri stars; Eclipsing binaries: EA/Algol = Algol type (separated), EB/Beta Lyrae = Beta Lyrae type (half separated), EW/W UMa = W Ursae Majoris type (contact); Other: RCrB/R CrB = Irregular variable, carbon stars
    max, min
    Maximum and minimum visual brightness in magnitudes; extreme values given.
    Period
    Period of variation in days
    Spectr
    Spectral type

    References

    Links


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    Last Modification: August 1, 1999