Anna N. Żytkow
| Discovered planetoids: 7 (Together with Michael Irwin) | |
|---|---|
| (8012) 1990 HO3 | 29 April 1990 |
| (8361) 1990 JN1 | 1 May 1990 |
| (15810) 1994 JR1 | 12 May 1994 |
| (16684) 1994 JQ1 | 11 May 1994 |
| (48443) 1990 HY5 | 29 April 1990 |
| (58165) 1990 HQ5 | 29 April 1990 |
| (73682) 1990 HU5 | 29 April 1990 |
Anna N. Żytkow (Polish pronunciation: [ˈanːa ˈʐɨtkɔf], born February 21, 1947) is a Polish astrophysicist working at the Institute of Astronomy of the University of Cambridge.[1][2]
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.[4] 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 a and engulfs its companion neutron star.[4]
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.
Kuiper belt discoveries
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.[6] 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.[6] 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.[6]
References
- ↑ Zimmermann, Mark (2000-05-01). "Soft Outside CrunchyCenter". zhurnaly.com. Retrieved 2011-07-24.
- ↑ "Dr Anna N Żytkow". University of Cambridge. Retrieved 2011-07-24.
- ↑ Thorne, Kip S.; Żytkow, Anna N. (15 March 1977). "Stars with degenerate neutron cores. I - Structure of equilibrium models" 212 (1). The Astrophysical Journal: 832–858. Bibcode:1977ApJ...212..832T. doi:10.1086/155109. Retrieved 2014-06-13.
- 1 2 3 Cannon, R.; Eggleton, P.; Zytkow, A.; Podsiadlowski, P. "The Structure and Evolution of Thorne-Zytkow Objects" (PDF). SAO/NASA Astrophysics Data System (ADS). Institute of Astronomy, Madingley Road, Cambridge, UK. Retrieved 30 October 2014.
- ↑ Levesque, Emily; Massey, Philip; Żytkow, Anna; Morrell, Nidia (30 May 2014). "Discovery of a Thorne-Zytkow object candidate in the Small Magellanic Cloud". Monthly Notices of the Royal Astronomical Society Letters 1406: 1. arXiv:1406.0001. Bibcode:2014MNRAS.443L..94L. doi:10.1093/mnrasl/slu080.
- 1 2 3 4 Żytkow, Anna; Irwin, Mike; Tremaine, Scott. "A Search for Slow-Moving Objects and the Luminosity Function of the Kuiper Belt". SAO/NASA Astrophysics Data System (ADS). Institute of Astronomy, Madingley Road, Cambridge, United Kingdom. Retrieved 29 October 2014.