Earth and Space News: William Herschel planetary nebula discoveries

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Wednesday, November 27, 2019

Sir John Herschel Made Three Observations of the Bow Tie Nebula NGC 40

Summary: John Herschel made three observations of the Bow Tie Nebula NGC 40, the planetary nebula discovered Nov. 25, 1788, by his father, William Herschel.

On Dec. 20, 1829, English polymath Sir John Herschel made his first of three observations of NGC 40, a planetary nebula in constellation Cepheus discovered by his father, Uranus discoverer Sir William Herschel, Nov. 25, 1788; 1829 miniature watercolor of John Herschel by Swiss portrait painter Alfred Edward Chalon, painted as complement to portrait of Margaret Brodie Stewart (Aug. 16, 1810-Aug. 3, 1884) for their marriage March 3, 1829: Public Domain, via Wikimedia Commons

Sir John Herschel made three observations of the Bow Tie Nebula NGC 40, a planetary nebula in Cepheus the King constellation discovered Nov. 25, 1788, by his father, Sir William Herschel.

German-British astronomer and composer Sir Frederick William Herschel (Nov. 15, 1738-Aug. 25, 1822) discovered NGC 40 seven years eight-plus months after his March 13, 1781, discovery of Uranus, the solar system’s seventh planet. Sir William made his discovery of NGC 40 at his last residence, known as Observatory House, in Slough, Royal County of Berkshire, South East England.

Sir William’s discovery of NGC 40 appears in his Catalogue of a Second Thousand of New Nebulae and Clusters of Stars, published in 1789. The discovery is entered as number 58 in the category of "IV. Fourth claſs. Planetary nebulae.”

Sir William’s only child, English polymath Sir John Frederick William Herschel, 1st Baronet (March 7, 1792-May 11, 1871), shared his father’s interest in astronomy. In 1852, Sir John named the four then-known moons of his father’s planet: Ariel, Umbriel, Titania and Oberon.

In 1833, Sir John published Observations of Nebulae and Clusters of Stars, Made at Slough, With a Twenty-Feet Reflector, Between the Years 1825 and 1833. The astronomical catalogue comprised his and his father’s observations. He arranged the catalogue’s entries “in order of right ascension,” the celestial equivalent of terrestrial longitude.

Sir William’s Cepheid planetary nebula appears as entry number 8 in Sir John’s 1833 publication. Sir William’s designation for his discovery, IV-58, is given as the synonym for entry number 8. Sir John noted three observations of his entry number 8.

The observations were made during sweeps 228, 378 and 380. Sweep 228 occurred Dec. 20, 1829. Sweep 378 took place Oct. 29, 1831. On Nov. 2, 1831, Sir John conducted sweep 380. Sir William and Sir John referred to their telescopic surveys of the sky as “sweeps of the heavens.”

Sir John began entry number 8 with details from sweep 378 (Oct. 29, 1831), which occurred chronologically as the second of his three observations. He described his observation of IV-58 as: “A * 10 m with strong neb atmosph 15” diameter. Exactly R and p suddenly fading away makes a D * class 5 with a * preceding.” His description translates as: “A star of the 10th magnitude with strong nebulous atmosphere, diameter of 15 arc seconds. Exactly round and pretty, suddenly fading away, makes a class 5 double star with a preceding star.”

The second set of details for entry number 8 came from sweep 380 (Nov. 2, 1831), which was actually the third, or most recent, of his three observations. His second observation remarked: “The L * of a D * strongly affected with a neb burr. Pos 241°^.4; △ AR = 25^s; 10 and 12 m.” His description translates as: “The large star of a double star strongly affected with a nebulous burr. Angle of position measured 241°^.4 by the micrometer; right ascension 25 seconds. 10th and 12th magnitude.”

Sweep 228 (Dec. 20, 1829), which chronologically marked Sir John’s first sighting of IV-58, supplied the third set of details for entry number 8. Sir John noted: “A star 11 m with a luminous atm 30 or 40” diam.” His description translates as: “A star of the 11th magnitude with a luminous atmosphere, diameter of 30 or 40 arcseconds.”

In 1865, Sir John published Catalogue of Nebulae and Clusters of Stars. The catalogue’s entry number 20 links with his 1833 catalogue’s entry number 8 and with Sir William’s IV-58 entry. He constructed his descriptions in the 1865 catalogue by assembling and comparing all observations and remarks given in his and his father’s catalogues. Sir John’s composite description of object IV-58 derived from his father’s sole discovery observation and from Sir John’s three observations.

Entry number 20 bears the composite description: “vF; vS; R; vsmbM *10; *12 241°^.4; 25^s.” The description translates as: “Very faint; very small; round; very suddenly much brighter in the middle, star of the 10th magnitude; star of the 12th magnitude, micrometrically measured 241°.4; 25 seconds.”

Sir William’s IV-58 and Sir John’s synonymous entries are now known as NGC 40. Danish-Irish astronomer John Louis Emil Dreyer (Feb. 13, 1852-Sept. 14, 1926) published A New General Catalogue in 1888 as a compilation of discoveries and observations by the father-and-son Herschels; Sir William’s sister Caroline (March 16, 1750-Jan. 9, 1848); and other observational astronomers.

The takeaway for Sir John Herschel’s three observations of the Bow Tie Nebula NGC 40 is that the English polymath’s observations revisited the Cepheid planetary nebula discovered Nov. 25, 1785, by his father, Uranus discoverer Sir William Herschel.

Hubble Space Telescope WFPC2 (Wide Field Planetary Camera 2) color image of NGC 40 (lower left), with the planetary nebula's central star; RA 00:12:56.42, DEC 72:31:37.0; Nov. 10, 1995; image NGC40 (color) WFPC2 f814w/f555w PC1 06119_01: HLA (Hubble Legacy Archive), via HLA-STScI (Space Telescope Science Institute)

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Bratton, Mark. The Complete Guide to the Herschel Objects: Sir William Herschel’s Star Clusters, Nebulae and Galaxies. Cambridge UK; New York NY; Melbourne, Australia; Madrid, Spain; Cape Town, South Africa; Singapore; São Paulo, Brazil; Delhi, India; Tokyo, Japan; Mexico City, Mexico: Cambridge University Press, 2011.

Dreyer, J.L.E. (John Louis Emil). “No. 40.” In: “A New General Catalogue of Nebulae and Clusters of Stars, Being the Catalogue of the Late Sir John F.W. Herschel, Bart., Revised, Corrected, and Enlarged.” Memoirs of the Royal Astronomical Society, vol. XLIX, part I: 15. London, England: Royal Astronomical Society, 1888.
Available @ https://ia800501.us.archive.org/14/items/newgeneralcatalo00dreyrich/newgeneralcatalo00dreyrich.pdf
Available via HathiTrust @ https://hdl.handle.net/2027/osu.32435078053089?urlappend=%3Bseq=21

Dreyer, J.L.E. (John Louis Emil). “A New General Catalogue of Nebulae and Clusters of Stars, Being the Catalogue of the Late Sir John F.W. Herschel, Bart., Revised, Corrected, and Enlarged.” Memoirs of the Royal Astronomical Society, vol. XLIX, part I. London, England: Royal Astronomical Society, 1888.
Available @ https://ia800501.us.archive.org/14/items/newgeneralcatalo00dreyrich/newgeneralcatalo00dreyrich.pdf
Available via HathiTrust @ https://hdl.handle.net/2027/osu.32435078053089

Dreyer, J.L.E. (John Louis Emil). “A Supplement to Sir John Herschel’s ‘General Catalogue of Nebulae and Clusters of Stars.’ (Read February 26, 1877.).” The Transactions of the Royal Irish Academy, vol. XXVI (March 1878). Dublin, Ireland: Royal Irish Academy, 1878.
Available via Internet Archive @ https://archive.org/details/supplementtosirj00dreyrich/

Herschel, Sir John Frederick William. “Catalogue of Nebulae and Clusters of Stars. Received October 16, -- Read November 19, 1863.” Philosophical Transactions of the Royal Society of London. For the Year MDCCCLXIV [1864]. Vol. 154: 1-137. London, England: Taylor and Francis, MDCCCLXV (1865).
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093164
Available via JSTOR @ https://www.jstor.org/stable/108864

Herschel, Sir John Frederick William. “No. 8.” In: “Observations of Nebulae and Clusters of Stars, Made at Slough, With a Twenty-Feet Reflector, Between the Years 1825 and 1833. Received July 1, -- Read November 21, 1833.” Philosophical Transactions of the Royal Society of London, vol. 123 (1833): 365.
Available via JSTOR @ https://www.jstor.org/stable/108003?seq=7#metadata_info_tab_contents

Herschel, Sir John Frederick William. “No. of Catalogue: 20.” In: “Catalogue of Nebulae and Clusters of Stars. Received October 16, -- Read November 19, 1863.” Philosophical Transactions of the Royal Society of London. For the Year MDCCCLXIV [1864]. Vol. 154: 46. London, England: Taylor and Francis, MDCCCLXV (1865).
Available via Biodiversity Heritage Library (Natural History Museum Library, London) @ https://biodiversitylibrary.org/page/54093209
Available via JSTOR @ https://www.jstor.org/stable/108864?seq=46#metadata_info_tab_contents

Herschel, Sir John Frederick William. “Observations of Nebulae and Clusters of Stars, Made at Slough, With a Twenty-Feet Reflector, Between the Years 1825 and 1833. Received July 1, -- Read November 21, 1833.” Philosophical Transactions of the Royal Society of London, vol. 123 (1833): 359-505.
Available via JSTOR @ https://www.jstor.org/stable/108003

Herschel, Sir John F.W. (Frederick William). Results of Astronomical Observations Made During the Years 1834, 5, 6, 7, 8, at the Cape of Good Hope: Being the Completion of a Telescopic Survey of the Whole Surface of the Visible Heavens, Commenced in 1825. London, England: Smith, Elder and Co., 1847.
Available via Internet Archive @ https://archive.org/details/resultsofastrono00hers/

Herschel, Sir John F.W. (Frederick William). “Synoptic Table of the Dates of the Sweeps.” In: Results of Astronomical Observations Made During the Years 1834, 5, 6, 7, 8, at the Cape of Good Hope: Being the Completion of a Telescopic Survey of the Whole Surface of the Visible Heavens, Commenced in 1825: 130-131. London, England: Smith, Elder and Co., 1847.
Available via Internet Archive @ https://archive.org/details/resultsofastrono00hers/page/130

Herschel, William. “IV. 58.” In: “Catalogue of a Second Thousand of New Nebulae and Clusters of Stars; With a Few Introductory Remarks on the Construction of the Heavens. Read June 11, 1789.” Philosophical Transactions of the Royal Society of London, vol. LXXIX, part II (1789): 248. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXIX.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51828778
Available via JSTOR @https://www.jstor.org/stable/106695

Herschel, William. “IV-64.” In: “Catalogue of 500 New Nebulae, Nebulous Stars, Planetary Nebulae, and Clusters of Stars; With Remarks on the Construction of the Heavens. Read July 1, 1802.” Philosophical Transactions of the Royal Society of London. For the Year MDCCCII [1802] [vol. 92], part II: 520. London, England: W. Bulmer and Co., MDCCCII.
Available via Biodiversity Heritage Library (Smithsonian Libraries) @ https://biodiversitylibrary.org/page/49130839
Available via Biodiversity Heritage Library (University of Toronto -- Robarts Library) @ https://biodiversitylibrary.org/page/22894708
Available via JSTOR @ https://www.jstor.org/stable/107131

Herschel, William. “Catalogue of 500 New Nebulae, Nebulous Stars, Planetary Nebulae, and Clusters of Stars; With Remarks on the Construction of the Heavens. Read July 1, 1802.” Philosophical Transactions of the Royal Society of London. For the Year MDCCCII [1802] [vol. 92], part II: 477-528. London, England: W. Bulmer and Co., MDCCCII.
Available via Biodiversity Heritage Library (Smithsonian Libraries) @ https://biodiversitylibrary.org/page/49130796
Available via Biodiversity Heritage Library (University of Toronto -- Robarts Library) @ https://biodiversitylibrary.org/page/22894665
Available via JSTOR @ https://www.jstor.org/stable/107131

Herschel, William. “Catalogue of a Second Thousand of New Nebulae and Clusters of Stars; With a Few Introductory Remarks on the Construction of the Heavens. Read June 11, 1789.” Philosophical Transactions of the Royal Society of London, vol. LXXIX, part II (1789): 212-255. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXIX.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51828742
Available via JSTOR @ https://www.jstor.org/stable/106695

Herschel, William. “Catalogue of One Thousand New Nebulae and Clusters of Stars. Read April 27, 1786.” Philosophical Transactions of the Royal Society of London, vol. LXXVI, part II (1786): 457-499. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXVI.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/48283813
Available via JSTOR @ https://www.jstor.org/stable/106639

Lassell, W. (William). “Beobachtungen der Uranus-Satelliten.” Astronomische Nachrichten, vol. 34 (vier und dreissigster band), no. 812: 325-328. June 1852.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://articles.adsabs.harvard.edu/full/1852AN.....34..325.
Available via HathiTrust @ https://hdl.handle.net/2027/umn.31951000600709p?urlappend=%3Bseq=183

Marriner, Derdriu. “Bow Tie Nebula NGC 40 Is a Planetary Nebula in Constellation Cepheus.” Earth and Space News. Wednesday, Nov. 6, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/11/bow-tie-nebula-ngc-40-is-planetary.html

Marriner, Derdriu. “Globular Cluster NGC 5634 Lies Midway Between Iota and Mu Virginis.” Earth and Space News. Wednesday, Feb. 27, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/02/globular-cluster-ngc-5634-lies-midway.html

Marriner, Derdriu. "Herschel Crater Hosts Eight Satellites in South Central Lunar Near Side." Earth and Space News. Wednesday, Aug. 31, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/08/herschel-crater-hosts-eight-satellites.html

Marriner, Derdriu. "Lunar Crater Herschel Honors German-British Astronomer William Herschel." Earth and Space News. Wednesday, Aug. 24, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/08/lunar-crater-herschel-honors-german.html

Marriner, Derdriu. "Star Hopping Between Gamma Cassiopeiae and Gamma Cephei Locates NGC 40." Earth and Space News. Wednesday, Nov. 13, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/11/star-hopping-between-gamma-cassiopeiae.html

Marriner, Derdriu. “Uranus the Blue Green Ice Giant: Sideways Seventh Planet From the Sun.” Earth and Space News. Friday, March 13, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/03/uranus-blue-green-ice-giant-sideways.html

Marriner, Derdriu. “Uranus Discovery 234 Years Ago on March 13, 1781, by Sir William Herschel.” Earth and Space News. Friday, March 13, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/03/uranus-discovery-234-years-ago-on-march.html

Marriner, Derdriu. “William Herschel Discovered Bow Tie Nebula NGC 40 Nov. 25, 1788.” Earth and Space News. Wednesday, Nov. 20, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/11/william-herschel-discovered-bow-tie.html

Marriner, Derdriu. “William Herschel Discovered NGC 665 and NGC 673 Sept. 4, 1786.” Earth and Space News. Wednesday, Aug. 28, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/08/william-herschel-discovered-lenticular.html

Marriner, Derdriu. “William Herschel Discovered NGC 6818, Little Gem Nebula, Aug. 8, 1787.” Earth and Space News. Wednesday, Aug. 7, 2019.
Available @ https://earth-and-space-news.blogspot.com/2019/08/william-herschel-discovered-ngc-6818.html

Mullaney, James. The Herschel Objects and How to Observe Them. AST Astronomers’ Observing Guides. New York NY: Springer Science+Business Media LLC, 2007.

Mullaney, James; Wil Tirion. The Cambridge Atlas of Herschel Objects. Cambridge, England; New York NY; Melbourne, Australia; Madrid, Spain; Cape Town, South Africa; Singapore; São Paulo, Brazil; Delhi, India; Dubai, United Arab Emirates; Tokyo, Japan; Mexico City: Mexico: Cambridge University Press, 2011.

O’Meara, Steve. Herschel 400 Observing Guide: How to Find and Explore 400 Star Clusters, Nebulae, and Galaxies Discovered by William and Caroline Herschel. Cambridge, England; New York NY; Melbourne, Australia; Madrid, Spain; Cape Town, South Africa; Singapore; São Paulo, Brazil: Cambridge University Press, 2007.

Steinicke, Wolfgang. “’Historic WH’ Columns.” Astronomie-Homepage von Wolfgang Steinicke > Current Matters: Historic WH > Discovery and Cataloguing of Nebulae and Star Clusters > 2. Historical Catalogues: W. Herschel: Historic WH > “Historic WH” -- Explanation. Jan. 14, 2018.
Available @ http://www.klima-luft.de/steinicke/ngcic/Expl_Hist_WH.htm

Steinicke, Wolfgang. Revised New General Catalogue and Index Catalogue. Jan. 14, 2018.
Available @ http://www.klima-luft.de/steinicke/ngcic/rev2000/Explan.htm#3.2

Wednesday, November 6, 2019

Bow Tie Nebula NGC 40 Is a Planetary Nebula in Constellation Cepheus

Summary: The Bow Tie Nebula NGC 40 is a planetary nebula in constellation Cepheus and owes its discovery Nov. 25, 1788, to Uranus discoverer Sir William Herschel.

Composite X-ray (blue)/optical (red) image of planetary nebula NGC 40 shows shell of multimillion degree gas (blue), compressed and heated by a 2-million-miles-per-hour stellar wind; the nebula (red) represents ejected matter that has been heated to about 10,000 degrees Celsius by radiation from the nebula’s star; bright point is NGC 40 nebula’s central star, which has a surface temperature of about 50,000 degrees Celsius: NASA/CXC/RIT/J. (Joel) Kastner & R. (Rodolpho) Montez (X-ray credit); NSF/AURA/NOAO/WIYN (Optical credit), via NASA’s Chandra X-Ray Observatory

The Bow Tie Nebula NGC 40 is a planetary nebula in Cepheus the King constellation that was discovered Nov. 25, 1788, by Sir William Herschel, seven years eight-plus months after his March 13, 1781, discovery of the solar system’s seventh planet, Uranus.

Sir William (Nov. 15, 1738-Aug. 25, 1822) recorded his discovery of the Cepheid planetary nebula as number 58 within his planetary nebula category. He determined the nebula’s location by way of fifth magnitude star 24 Cephei. Sir William described IV-58 as having a “very faint milky nebulosity.”

Sir William’s IV-58 is now known as NGC (New General Catalogue) 40. The Cepheid planetary nebula appears as number 40 in A New General Catalogue, published in 1888 by Danish-Irish astronomer John Louis Emil Dreyer (Feb. 13, 1852-Sept. 14, 1926).

NGC 40 is located in Cepheus the King, one of the Northern Hemisphere’s five circumpolar constellations. The Northern Hemisphere’s circumpolar constellations lie closest to the celestial north pole.

The planetary nebula’s equatorial coordinates are right ascension of 00 hours 13 minutes 01.030 seconds, declination of plus 72 degrees 31 minutes 19.00 seconds (epoch J2000.0), according to the NASA/IPAC Extragalactic (NED) Database. Right ascension (abbreviated RA; symbol α) and declination (abbreviated dec; symbol δ) are the celestial counterparts to terrestrial longitude and latitude, respectively.

The planetary nebula’s “determining star,” 24 Cephei, is identified in the Hipparcos Catalogue as HIP 109400. The Hipparcos Catalogue, released in June 1997, provides precise astrometric data for 118,218 stars. The catalogue’s data comes from Hipparcos (High Precision Parallax Collecting Satellite), a scientific satellite launched Aug. 8, 1989, by the European Space Agency (ESA) and deactivated Aug. 15, 1993.

The equatorial coordinates for HIP 109400 (24 Cephei) are right ascension of 22:09:48.430, declination of plus 72:20:28.34, according to Hubble Legacy Archive (HLA). Hubble Legacy Archive is an online project of Hubble products jointly administered by the Space Telescope Science Institute (STScI), the Space Telescope European Coordinating Facility (ST-ECF) and the Canadian Astronomy Data Centre (CADC).

A planetary nebula forms from ionized gases ejected by a dying star. The dying central star in NGC 40 has a surface temperature of about 50,000 degrees Celsius, according to Rochester Institute of Technology’s press release of May 30, 2005. The ejected matter that shapes NGC 40’s nebula heats to about 10,000 degrees from the hot, dying star’s radiation. The central star’s stellar wind of 2 million miles per hour compresses and heats a shell of multimillion degree gas, according to a study in the December 2005 issue of the Astrophysics Journal. The hot bubble of gas also heats previously ejected gas to the point of emitting X-rays, according to the study’s team of Rodolpho Montez Jr. of the University of Rochester, Joel Kastner of the Rochester Institute of Technology, Orsola de Marco of New York’s American Museum of Natural History (AMNH) and Noam Soker of the Technion Institute in Haifa, Israel.

The Two Micron All Sky Survey (2MASS) collected astrometric and photometric data of 99.998 percent of the near-infrared celestial sphere between June 1997 and February 2001. The survey’s Atlas Images combine “raw survey data frames (which were taken six-deep in any direction in the sky) into a final uniform image.”

The Two Micron All Sky Survey’s website describes the Atlas Image of NGC 40 as revealing “an elliptical-shaped shell highlighted by the bright east and west lobes. NGC 40 is fated to fade away, while the central star eventually classifies as a white dwarf with a cooling off lasting “over billions of years.”

The takeaways for the Bow Tie Nebula NGC 40 in Cepheus the King constellation are that the planetary nebula, which was discovered by Uranus discoverer William Herschel, has an elliptical shape and that the present phase of superheated gas has created an X-ray emitting shell within NGC 40.

Planetary nebula NGC 40, discovered by Uranus discover Sir William Herschel, is located in Cepheus the King constellation, at a distance of about 3,000 light years from Earth; composite Chandra X-ray (red)/NOAO optical (black and white) image of NGC 40 presents “an alternative false-color scheme of the dying, Sun-like star”: NASA/CXC/RIT/J. (Joel) Kastner & R. (Rodolpho) Montez (X-ray credit); NSF/AURA/NOAO/WIYN (Optical credit), via NASA’s Chandra X-Ray Observatory

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Planetary nebula NGC 40, discovered by Uranus discover Sir William Herschel, is located in Cepheus the King constellation, at a distance of about 3,000 to 4,000 light years from Earth; composite Chandra X-ray (red)/NOAO optical (black and white) image of NGC 40 presents “an alternative false-color scheme of the dying, Sun-like star”: NASA/CXC/RIT/J. (Joel) Kastner & R. (Rodolpho) Montez (X-ray credit); NSF/AURA/NOAO/WIYN (Optical credit), via NASA’s Chandra X-Ray Observatory @ http://chandra.harvard.edu/photo/2005/n40/more.html

For further information:

Bratton, Mark. The Complete Guide to the Herschel Objects: Sir William Herschel’s Star Clusters, Nebulae and Galaxies. Cambridge, UK; New York NY; Melbourne, Australia; Madrid, Spain; Cape Town, South Africa; Singapore; São Paulo, Brazil; Delhi, India; Tokyo, Japan; Mexico City, Mexico: Cambridge University Press, 2011.

Galowicz, Susan. “Astronomers Find New Evidence for the Violent Demise of Sun-Like Stars.” Chandra X-Ray Observatory > Press Room. June 6, 2005.
Available @ http://chandra.harvard.edu/press/05_releases/press_060605.html

Galowicz, Susan. “Astronomers Find New Evidence for the Violent Demise of Sun-Like Stars.” Rochester Institute of Technology > University News. May 30, 2005.
Available @ https://www.rit.edu/news/story.php?id=44142

Herschel, William . “Catalogue of One Thousand New Nebulae and Clusters of Stars. Read April 27, 1786.” Philosophical Transactions of the Royal Society of London, vol. LXXVI, part II (1786): 457-499. London, England: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCLXXXVI.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/48283813
Available via JSTOR @ https://www.jstor.org/stable/106639

Jet Propulsion Laboratory, California Institute of Technology. “Index for NGC 0040.” NASA/IPAC Extragalactic Database (NED).
Available @ http://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Obj_id&objid=168365

Mandel, Steve and Paul; Adam Block; NOAO (National Optical Astronomy Observatory); AURA (Association of Universities for Research in Astronomy); NSF (National Science Foundation). “NGC 40: The Bow-Tie Nebula.” National Optical Astronomy Observatory > Kitt Peak Visitor Center > Best of AOP -- Planetary Nebulae.
Available @ https://www.noao.edu/kpvc/observers/n40.html

Montez, Rodolfo, Jr.; Joel H. Kastner; Orsola De Marco; and Noam Soker. “X-Ray Imaging of Planetary Nebulae With Wolf-Rayet-Type Central Stars: Detection of the Hot Bubble in NGC 40.” The Astrophysical Journal, vol. 635 (Dec. 10, 2005): 381-385.
Available via IOPscience @ http://iopscience.iop.org/article/10.1086/497262/fulltext/

Mullaney, James. The Herschel Objects and How to Observe Them. AST Astronomers’ Observing Guides. New York NY: Springer Science+Business Media LLC, 2007.

Seligman, Courtney. “NGC 7302 (= NGC 40, the Bow-Tie Nebula (= P-K 120+09.1 = "PGC 2923327")).” Courtney Seligman Website > Online Astronomy Text > Sky Atlas > NGC Objects > NGC 7300-7349.
Available @ http://cseligman.com/text/atlas/ngc0.htm

Skrutskie, M. (Michael) F.; et al. “The Two Micron All Sky Survey (2MASS).” The Astronomical Journal, vol. 131, no. 2 (February 2006): 1163-1183.
Available via IOP Science @ http://iopscience.iop.org/article/10.1086/498708/pdf

Space Telescope Science Institute (STScI); Space Telescope European Coordinating Facility (ST-ECF); Canadian Astronomy Data Centre (CADC). “HIP 109400.” Hubble Legacy Archive.
Available @ https://hla.stsci.edu/hlaview.html#Inventory|filterText%3D|query_string=HIP%20109400

Space Telescope Science Institute (STScI); Space Telescope European Coordinating Facility (ST-ECF); Canadian Astronomy Data Centre (CADC). “NGC 40.” Hubble Legacy Archive.
Available @ https://hla.stsci.edu/hlaview.html#Inventory|filterText%3D%24filterTypes%3D|query_string=ngc%2040

Steinicke, Wolfgang. Revised New General Catalogue and Index Catalogue. Jan. 14, 2018.
Available @ http://www.klima-luft.de/steinicke/ngcic/rev2000/Explan.htm#3.2

Wednesday, August 7, 2019

William Herschel Discovered NGC 6818, Little Gem Nebula, Aug. 8, 1787

Summary: Uranus discoverer William Herschel discovered lenticular galaxy NGC 665 Sept. 4, 1786, five years five-plus months after discovering Uranus March 13, 1781.

NGC 665 appears as II-588 in Uranus discoverer Sir William Herschel’s list of “II. Second Class. Faint Nebulae” discoveries; the lenticular galaxy in Pisces was the first of two galaxies that he discovered Sep. 4, 1786: Sloan Digital Sky Survey (SDSS), CC BY 4.0 International, via Wikimedia Commons

Uranus discoverer William Herschel discovered lenticular galaxy NGC 665 Sept. 4, 1786, five years five-plus months after his discovery of the solar system’s seventh planet, Uranus, which happened March 13, 1781.

German-British astronomer and composer Sir Frederick William Herschel (Nov. 15, 1738-Aug. 25, 1822) made his discovery of NGC 665 at his observatory residence, Observatory House, on Windsor Road in Slough, Royal County of Berkshire, south east England. Wolfgang Steinecke, Director of the Webb Deep-Sky Society’s Nebulae and Clusters Section, identifies the instrument used for the two consecutive discoveries as Herschel’s 20-foot, long-focus Newtonian reflector telescope. The model’s mirror measured 18.7 inches.

Sir William’s discovery Sept. 4, 1786, appear as number 588 under “II. Second Class. Faint Nebulae” in his Catalogue of a Second Thousand of New Nebulae and Clusters of Stars, published in 1789. He organized his discoveries of new nebulae and star clusters into eight classes. The first class comprised “Bright nebulae.” Classes three through eight itemized, respectively, “Very faint nebulae”; “Planetary nebulae”; “Very large nebulae”; “Very compressed and rich clusters of stars”; “Pretty much compressed clusters of large or small stars”; “Coarsely scattered clusters of stars.”

Sir William’s three deep-sky catalogues, published in 1786, 1789 and 1802, followed an identical format that included identifying “the star, or other object” that “is either preceding or following” the nebula. Object II-588 precedes “24 (ξ) Ariet,” a binary star in Aries the Ram constellation.

Sir William referenced the “determining star” by both Bayer and Flamsteed stellar designations. German celestial cartographer Johann Bayer (1572-March 7, 1625) specified stars with designators comprising a Greek or Latin letter preceding the genitive form of the parent constellation’s Latin name. The Bayer designation for the “determining star” is ξ Arietis (Xi Arietis), which is abbreviated as ξ Ari (Xi Ari). Devised by the United Kingdom’s first Astronomer Royal, John Flamsteed (Aug. 19, 1646-Dec. 31, 1719), the Flamsteed system designates stars with a number preceding the Latin genitive of the parent constellation. The Flamsteed designation for Xi Arietis is 24 Arietis.

According to Sir William’s observations, II-588 precedes Xi Arietis by a sidereal time of 39 minutes 40 seconds. His calculations determined the location of II-588 as 0 degrees 17 minutes south of the “determining star.”

Sir William indicated that he had made two observations of II-588. He used a system of abbreviations for describing his observations. Sir William perceived II-588 as “F. S. lE r. bM.” According to his code of abbreviations, his description of 588 translates as: “Faint. Small. A little extended, resolvable. Brighter in the middle.”

Sir William’s faint nebula number 588 is identified as NGC 665 in the New General Catalogue, published in 1888 by Danish-Irish astronomer John Louis Emil Dreyer (Feb. 13, 1852-Sept. 14, 1926). Dreyer’s compilation assigns NGC (New General Catalog) numbers to discoveries and observations by Sir William; his son, Sir John Frederick William Herschel, 1st Baronet (March 7, 1792-May 11, 1871); his sister, Caroline Herschel (March 16, 1750-Jan. 9, 1848); and other observational astronomers. The entries are presented in order of right ascension (celestial equivalent of terrestrial longitude).

NGC 665 is located in celestial equatorial constellation Pisces the Fishes. The galaxy’s equatorial coordinates are right ascension of 01 hour 44 minutes 56.10 seconds, declination of plus 10 degrees 25 minutes 22.9 seconds (epoch J2000.0), according to NASA/IPAC Extragalactic Database (NED).

The NED Database indicates that NGC 665 falls within the galaxy morphological classification designated as (R)S0^0, a lenticular galaxy with an outer ring. Ronald J. Buta, a University of Alabama astronomy professor specializing in galactic morphology, explains that outer rings are “occasionally seen enveloping the main bodies of early-type spirals and lenticulars.”

A lenticular galaxy (designated S0) displays an extended, disk-like structure surrounding a bright, central concentration, known as the bulge. NGC 665 is a 12th magnitude lenticular galaxy, according to the online Celestial Atlas of NGC Objects maintained by Courtney Seligman, Professor Emeritus of Astronomy at California’s Long Beach City College.

Object II-588 was the first of two galaxies discovered Sept. 4, 1786, by William Herschel. The second galaxy, object II-589, is now known as NGC 673 and lies in the neighboring constellation of Aries the Ram.

The takeaway for NGC 665, discovered Sept. 4, 1786, as II-588 by Uranus discoverer Sir William Herschel, is that lenticular galaxy claims Pisces the Fishes as parent constellation.

Hubble Space Telescope image of NGC 665; RA 01:44:56.49, DEC 10:25:28.3; Nov. 7, 2016; image ICV408JJQ: HLA (Hubble Legacy Archive), via HLA-STScI (Space Telescope Science Institute)

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

NGC 665 appeared as II.588 in Uranus discoverer Sir William Herschel’s list of “II. Second Class. Faint Nebulae” discoveries; the lenticular galaxy in Pisces was the first of two galaxies that he discovered Sep. 4, 1786: Sloan Digital Sky Survey (SDSS), CC BY 4.0 International, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:NGC665_-_SDSS_DR14.png

Hubble Space Telescope image of NGC 665; RA 01:44:56.49, DEC 10:25:28.3; Nov. 7, 2016; image ICV408JJQ: HLA (Hubble Legacy Archive), via HLA-STScI (Space Telescope Science Institute) @ https://hla.stsci.edu/hlaview.html#Inventory|filterText%3D%24filterTypes%3D|query_string=ngc%20665

For further information:

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Buta, Ronald. “Galaxy Morphology and Classification.” Pages 29-47. In: Harold G. Corwin, Jr., and Lucette Bottinelli, eds. The World of Galaxies: Proceedings of the Conference “Le Monde des Galaxies” Held 12-14 April 1988 at the Institut d’Astrophysique de Paris in Honor of Gérard and Antoinette de Vaucouleurs on the Occasion of His 70th Birthday. New York NY: Springer-Verlag, 1989.
Available via NASA/IPAC Extragalactic Database (NED) @ https://ned.ipac.caltech.edu/level5/March01/Buta/frames.html

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Available via HathiTrust @ https://hdl.handle.net/2027/osu.32435078053089?urlappend=%3Bseq=38

Herschel, Sir John F.W. (Frederick William). “394.” In: “A General Catalogue of Nebulae and Clusters of Stars, Arranged in Order of Right Ascension and Reduced to the Common Epoch 1860.0 (With Precessions Computed for the Epoch 1880.0). Received October 16, -- Read November 19, 1863.” Philosophical Transactions, Part I (1864): 52. London, England: Taylor and Francis, 1864.
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Available via Internet Archive @ https://archive.org/details/sirwilliamhersch00holduoft/

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Seligman, Courtney. “NGC 665 (= PGC 6415).” Courtney Seligmen Website > Online Astronomy Text > Sky Atlas > NGC Objects > NGC 650-699.
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