|Title||Low-Mass Companions of Cepheids: Fingerprints of Star Formation|
|Author||Dr Nancy Remage Evans|
|Description||Star-formation theory should be able to reproduce the binary characteristics (separation, mass ratio, eccentricity) for high- and intermediate-mass stars; but first we have to define, through observations, what those characteristics are. This project proposes XMM X-ray observations of a sample of 8 possible companions of 5 Msun Cepheids to confirm that they are young physical companions, not chance alignments with field stars. The sample is a subset of 69 Cepheids surveyed with the Hubble Space Telescope Wide Field Camera 3 (WFC3), identifying 35 possible low-mass companions. They have the surprising characteristic that there are more F-G dwarfs (compared to K dwarfs) than predicted by the Initial Mass Function, a ''fingerprint" of binary star formation|
|Publication||Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids . Evans, Nancy Remage, Bond, Howard E., et all. . AJ . 151-129 . 2016 . 2016AJ....151..129E ,
Resolved Companions of Cepheids: Testing the Candidates with X-Ray Observations . Evans, Nancy Remage, Pillitteri, Ignazio, et all. . AJ . 151-108 . 2016 . 2016AJ....151..108E ,
The Million Optical - Radio-X-ray Associations (MORX) Catalogue . Flesch, Eric W., . PASA . 33-52 . 2016 . 2016PASA...33...52F ,
The Secret Lives of Cepheids: delta Cep---The Prototype of a New Class of Pulsating X-Ray Variable Stars . Engle, Scott G., Guinan, Edward F., et all. . ApJ . 838-67 . 2017 . 2017ApJ...838...67E ,
X-Ray Observations of the Peculiar Cepheid V473 Lyr Identify A Low-mass Companion . Evans, Nancy Remage, Pillitteri, Ignazio, et all. . AJ . 159-121 . 2020 . 2020AJ....159..121E ,
|Instrument||EMOS1, EMOS2, EPN, OM, RGS1, RGS2|
|Mission Description||The European Space Agency's (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESA's second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations.
Since Earth's atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
|Publisher And Registrant||European Space Agency|
|Credit Guidelines||European Space Agency, 2015-02-10T23:00:00Z, 072030, PPS_NOT_AVAILABLE. https://doi.org/10.5270/esa-kbghuvt|