Anna N. Żytkow Explained

Anna N. Żytkow
Birth Date:21 February 1947
Birth Place:Poland
Education:University of Warsaw
Nationality:Polish
Field:Astrophysics
Work Institutions:Institute of Astronomy, Cambridge of the University of Cambridge
Known For:Thorne–Żytkow object

Anna Nikola Żytkow (pronounced as /pl/; born 21 February 1947) is a Polish astrophysicist working at the Institute of Astronomy of the University of Cambridge.[1] [2] Żytkow and Kip Thorne proposed a model for what is called the Thorne–Żytkow object, which is a star within another star. Żytkow in 2014 was part of the team led by Emily M. Levesque which discovered the first candidate for such an object.

Thorne-Żytkow objects

Working together with Kip Thorne in 1976, Żytkow developed a theoretical model for a new star type, the Thorne–Żytkow object (TŻO),[3] which contains either a neutron star or a black hole core at the center of a stellar envelope. The evolution of such a star occurs rarely and only two processes exist that define the structure and evolution of a TŻO.[4] In the first process a collision between a neutron star and a normal star, either dwarf or giant, must occur in order to merge the two into a single object. This occurrence is rare since stars do not usually collide with each other. This could only happen in a dense cluster of stars. The second possible evolution of a larger TŻO can occur when a star expands into a red supergiant and engulfs its companion neutron star.

A team led by Emily Levesque (University of Colorado at Boulder) and including Anna Żytkow found the first viable TŻO candidate using the 6.5-meter Magellan Clay Telescope at Las Campanas Observatory in 2014,[5] possibly succeeding in a search for these bizarre stars, one that had already spanned some 40 years worth of effort.

Żytkow said upon the discovery: "I am extremely happy that observational confirmation of our theoretical prediction has started to emerge. Since Kip Thorne and I proposed our models of stars with neutron cores, people were not able to disprove our work. If theory is sound, experimental confirmation shows up sooner or later. So it was a matter of identification of a promising group of stars, getting telescope time and proceeding with the project."

Personal life

Żytkow's career was interrupted by a mountaineering accident that nearly took her life.

Kuiper belt discoveries

Minor planets discovered: 7 
29 April 1990
1 May 1990
12 May 1994
11 May 1994
29 April 1990
29 April 1990
29 April 1990
all co-discovered with Mike Irwin
In December 1995, Mike Irwin, Scott Tremaine, and Anna N. Żytkow collaborated on the survey of two slow-moving objects, which are probable members of the Kuiper belt. Żytkow and the group followed Edgeworth (1949) and Kuipers (1951) research, which indicates that protoplanetary disks extend beyond Neptune and that the disk material beyond Neptune had not coalesced into planets.[6] This group of planetesimals is now known as the Kuiper belt. Żytkow and the rest of the group members spent most of their time adjusting the focus of the camera and instruments attached to the Isaac Newton Telescope (INT). The group used the Monte Carlo method, which provided multiple simulations in two separate stages. The first stage is the detection rate for images that came from INT as a function of magnitude, which was investigated using artificial images adding to the original frames. The second stage involved examining the detection rate for a series of artificial images from INT that followed the typical slow moving solar system objects (SMO) track. The outcome of this survey was a detection of two new Kuiper belts objects within the area of 0.7 degree sq. to a limiting magnitude mR=23.5.

Publications

External links

Notes and References

  1. Web site: Soft Outside CrunchyCenter. 2011-07-24. Mark. Zimmermann. ZhurnalyWiki . 2000-05-01. 28 June 2012. https://web.archive.org/web/20120628155103/http://zhurnaly.com/cgi-bin/wiki/SoftOutsideCrunchyCenter. dead.
  2. Web site: Dr Anna N Żytkow. 2011-07-24. University of Cambridge. dead . https://web.archive.org/web/20120526071740/http://www.ast.cam.ac.uk/people/Anna.N.Zytkow . May 26, 2012 .
  3. Stars with degenerate neutron cores. I - Structure of equilibrium models . Kip S. . Thorne . Kip Thorne . Anna N. . Żytkow . The Astrophysical Journal. 212 . 1 . 15 March 1977 . 832–858 . 10.1086/155109 . 1977ApJ...212..832T . free . free . NASA/ADS . live . https://web.archive.org/web/20230410021542/https://articles.adsabs.harvard.edu/pdf/1977ApJ...212..832T . Apr 10, 2023 .
  4. Cannon. R.. Eggleton. P.. Zytkow. A.. Podsiadlowski. P.. The Structure and Evolution of Thorne-Zytkow Objects. The Astrophysical Journal. 386. 206. Institute of Astronomy, Madingley Road, Cambridge, UK. 1992ApJ...386..206C. 1992. 10.1086/171006 . free . free . NASA/ADS . live . https://web.archive.org/web/20230530073715/https://articles.adsabs.harvard.edu/pdf/1992ApJ...386..206C . May 30, 2023 .
  5. Levesque . Emily . Massey . Philip . Anna . Żytkow . Anna N. Żytkow. Morrell . Nidia . Nidia Morrell . Discovery of a Thorne-Zytkow object candidate in the Small Magellanic Cloud . 1406.0001 . . 1406 . L94–L98 . 30 May 2014 . 2014MNRAS.443L..94L . 10.1093/mnrasl/slu080 . free . free . Oxford Academic . live . https://archive.today/20240628021559/https://academic.oup.com/mnrasl/article/443/1/L94/1054019 . 28 Jun 2024 .
  6. Żytkow. Anna. Irwin. Mike. Tremaine. Scott. A Search for Slow-Moving Objects and the Luminosity Function of the Kuiper Belt. The Astronomical Journal. 110. 3082. Institute of Astronomy, Madingley Road, Cambridge, United Kingdom. 1995AJ....110.3082I. 1995. 10.1086/117749.