Gerald Kron | |
|---|---|
| Born | (1913-04-06)April 6, 1913 |
| Died | April 9, 2012(2012-04-09) (aged 99) |
| Alma mater | University of Wisconsin-Madison University of California |
| Known for | photometry discovery ofstarspots |
| Scientific career | |
| Fields | astronomy |
| Institutions | MIT Radiation Laboratory Naval Ordnance Test Station Lick Observatory United States Naval Observatory Australian National University |
| Doctoral advisor | Joel Stebbins |
Gerald Kron (April 6, 1913 – April 9, 2012) was an American astronomer who was one of the pioneers of high-precisionphotometry with photoelectric instrumentation. He discovered the firststarspot and made the first photometric observation of astellar flare.
A graduate of theUniversity of Wisconsin-Madison, where he earned aMaster of Science degree inmechanical engineering in 1934, Kron became interested inastronomy, which he studied underJoel Stebbins. Stebbins arranged for Kron to enter theUniversity of California at Berkeley, where he received his doctorate in astronomy in 1938.
DuringWorld War II, Kron served with theRadiation Laboratory at theMassachusetts Institute of Technology, and participated in the development ofmicrowave radar. He later became the head of the Special Devices Group at theNaval Ordnance Test Station (NOTS) atInyokern, California, where he conducted studies on solid fuel rockets, and developed radiotransponders for theManhattan Project'sProject Camel.
After the war Kron returned to theLick Observatory, where he was one of the designers of theC. Donald Shane telescope. Using photometric techniques that he had pioneered before the war, he studied the stars, especiallyeclipsing binaries. In 1965, Kron became director of theUnited States Naval Observatory inFlagstaff, Arizona, and he was a regular visitor to theAustralian National University'sMount Stromlo Observatory.
Gerald Edward Kron was born inMilwaukee on 6 April 1913, the son of Edmund Kron, a mechanic, and his wife Letty Dieterick Kron. He attendedLincoln High School in Milwaukee, and thenUniversity of Wisconsin-Madison, where he earned aMaster of Science degree inmechanical engineering in 1934.[1][2] While there took advantage of the access to machine shops as part of his training to design and build a 6-inch telescope. After graduation, he received a scholarship to studyastronomy for two years underJoel Stebbins.[3][4] He published his first paper in 1935, a study of the photometric elements ofBoss 5070, aneclipsing binary.[3][5]
In 1935, Kron travelled to California with Stebbins andAlbert Whitford, where Kron and Whitford assisted Stebbins at theMount Wilson Observatory. After returning to Madison, he worked with Whitford on the design of a 200-inch telescope. Stebbins arranged for Kron to enter theUniversity of California at Berkeley,[3] where he received his doctorate in astronomy in 1938,[2] with a thesis on the photometric elements of eclipsing binaries.[4][6] He then worked in theLick Observatory as a research assistant.[2]
In May 1940 Kron joined theRadiation Laboratory at theMassachusetts Institute of Technology, and participated in the development ofmicrowave radar.[3] He would later use devices and equipment that he became familiar with at the Radiation Laboratory such as the RCA IP21photomultiplier andDirect-coupled amplifiers in looking at the stars.[4] Later inWorld War II he became head of the Special Devices Group at theNaval Ordnance Test Station (NOTS) atInyokern, California, where he conducted studies on solid fuel rockets.[2]
He also participated in theManhattan Project'sProject Camel, developing instrumentation to evaluate the test drops of nuclear bomb shapes.[7] Radiotransponders with timing pulses attached to the bombs allowed their position to be tracked the release of the bomb until the time it was all destroyed when the bomb detonated in the air or hit the ground. This gave the drop time to within a few hundredths of a second. In the course of his duties he visitedKingman andWendover Army Air Fields.[3] When the war ended, he "liberated" some equipment from NOTS before it could be destroyed.[4]
After the war Kron returned to the Lick Observatory, where he was one of the designers and creators of theC. Donald Shane telescope.[2] During the war, Kron met Katherine Carson Gordon, aVassar College graduate and aRadcliff College student, at a picnic atOak Ridge, Tennessee. After the war, she became an assistant at Lick Observatory.[3] He married her on 22 April 1946.[2] She continued publishing papers under her maiden name.[3]
The two worked together, looking at eclipsing binaries. At one point they found an irregularity, which they attributed to an area of colder temperature, astarspot. His observation and explanation were correct, but he was ahead of his time. It would be many years before the existence of starspots was accepted, and they became a popular research topic. They also made the first photometric observation of astellar flare.[4][8]
In 1965, Kron became director of theUnited States Naval Observatory inFlagstaff, Arizona. He regularly visitedCanberra in Australia, where theMount Stromlo Observatory allowed him to studyM-type dwarf stars in the southern sky. He was senior research fellow at theAustralian National University in Canberra from 1974 to 1976. He retired in 1985 to live inHonolulu, but moved toSedona, Arizona, in 1995.[2][4]
Kron served for a time as President of the Astronomical Society of the Pacific, and the International Astronomical Union's Commission on Instrumentation. He was elected a Fellow of theRoyal Astronomical Society.[2]
Kron published over 130 scientific papers, many of them described the method accurately measure the light of stars and globular clusters. He pioneered the use ofphotomultiplier tubes to measure the infrared radiation of cold stars. His measurements ofglobular clusters in theLarge Magellanic Cloud revised earlier views on distances outside theMilky Way Galaxy.[2]
He died on 12 April 2012. His wife Katherine and son Donald predeceased him. He was survived by his brother Robert and his remaining four children, Richard, Jenny, Virginia and Charles.[2]
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