Paul Kalas

Last updated
Paul Kalas
Paul Kalas in 2015.jpg
Paul Kalas in 2015, Cerro Pachón, Chile
Born (1967-08-13) August 13, 1967 (age 56)
New York City, United States
Alma mater University of Hawaiʻi
University of Michigan
Known for Exoplanet Research
Fomalhaut, Fomalhaut b
Awards Newcomb Cleveland Prize (2009)
Scientific career
Fields Astronomy
Institutions University of California, Berkeley
Doctoral advisor David Jewitt

Paul Kalas (born August 13, 1967) is a Greek American astronomer known for his discoveries of debris disks around stars. Kalas led a team of scientists to obtain the first visible-light images of an extrasolar planet with orbital motion around the star Fomalhaut, at a distance of 25 light years from Earth. [1] [2] The planet is referred to as Fomalhaut b.

Contents

Background

Kalas was born in New York City to George Kavallinis and Maria Drettakis, who immigrated to the United States from Heraklion, Crete. Kalas attended Detroit Country Day School in Michigan, and studied astronomy and physics at the University of Michigan, Ann Arbor. He earned a Doctor of Philosophy in Astronomy in 1996 from the University of Hawaiʻi under the direction of astronomer David Jewitt.

Kalas worked as a postdoctoral scientist at the Max Planck Institute for Astronomy in Heidelberg, Germany, the Space Telescope Science Institute, and the University of California, Berkeley. In 2006, he became an adjunct professor of astronomy at the University of California, Berkeley.

Kalas lives with his wife Aspasia Gkika and daughters Maria-Nikoleta and Natalia near Berkeley, California. [3]

Discoveries

Kalas discovered several circumstellar disks using a coronagraph on the Hubble Space Telescope and at the University of Hawaii 2.2-meter telescope at Mauna Kea, Hawaii. In 1995 he discovered various forms of asymmetric structures in optical images of the Beta Pictoris disk. [4] He was the lead scientist for the first optical images of debris disks surrounding the nearby red dwarf AU Microscopii and the bright star Fomalhaut. [5] [6]

Kalas' Hubble Space Telescope image of Fomalhaut revealed a narrow belt of dusty material analogous to our Solar System's Kuiper Belt. However, Kalas also found that Fomalhaut's belt is narrow and geometrically offset from the star by 15 astronomical units. These features are considered strong evidence for an extrasolar planet orbiting Fomalhaut that gravitationally sculpts the morphology of the belt.

Circumstellar disks discovered: 5
AU Microscopii [6] October 14, 2003
Fomalhaut [5] May 17, 2004
HD 15115 [7] July 17, 2006
HD 53143 [8] September 11, 2004
HD 139664 [8] October 14, 2004

Honors

Selected publications

Articles

Books

Related Research Articles

<span class="mw-page-title-main">Ring system</span> Ring of cosmic dust orbiting an astronomical object

A ring system is a disc or torus orbiting an astronomical object that is composed of solid material such as gas, dust, meteoroids, planetoids or moonlets and stellar objects.

<span class="mw-page-title-main">Fomalhaut</span> Triple star system in the constellation Piscis Austrinus

Fomalhaut is the brightest star in the southern constellation of Piscis Austrinus, the Southern Fish, and one of the brightest stars in the night sky. It has the Bayer designation Alpha Piscis Austrini, which is an alternative form of α Piscis Austrini, and is abbreviated Alpha PsA or α PsA. This is a class A star on the main sequence approximately 25 light-years (7.7 pc) from the Sun as measured by the Hipparcos astrometry satellite. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.

<span class="mw-page-title-main">Protoplanetary disk</span> Gas and dust surrounding a newly formed star

A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may not be considered an accretion disk, while the two are similar. While they are similar, an accretion disk is hotter, and spins much faster. It is also found on black holes, not stars. This process should not be confused with the accretion process thought to build up the planets themselves. Externally illuminated photo-evaporating protoplanetary disks are called proplyds.

<span class="mw-page-title-main">Beta Pictoris</span> Second brightest star in the southern constellation of Pictor

Beta Pictoris is the second brightest star in the constellation Pictor. It is located 63.4 light-years (19.4 pc) from the Solar System, and is 1.75 times as massive and 8.7 times as luminous as the Sun. The Beta Pictoris system is very young, only 20 to 26 million years old, although it is already in the main sequence stage of its evolution. Beta Pictoris is the title member of the Beta Pictoris moving group, an association of young stars which share the same motion through space and have the same age.

<span class="mw-page-title-main">AU Microscopii</span> Star in the constellation Microscopium

AU Microscopii is a young red dwarf star located 31.7 light-years away – about 8 times as far as the closest star after the Sun. The apparent visual magnitude of AU Microscopii is 8.73, which is too dim to be seen with the naked eye. It was given this designation because it is in the southern constellation Microscopium and is a variable star. Like β Pictoris, AU Microscopii has a circumstellar disk of dust known as a debris disk and at least two exoplanets, with the presence of an additional two planets being likely.

<span class="mw-page-title-main">HD 10647</span> Star in the constellation Eridanus

HD 10647 is a 6th-magnitude yellow-white dwarf star, 57 light-years away in the constellation of Eridanus. The star is visible to the unaided eye under very dark skies. It is slightly hotter and more luminous than the Sun, and at 1.75 billion years old, it is also younger. An extrasolar planet was discovered orbiting this star in 2003.

HD 210277 is a single star in the equatorial constellation of Aquarius. It has an apparent visual magnitude of 6.54, which makes it a challenge to view with the naked eye, but it is easily visible in binoculars. The star is located at a distance of 69.6 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −20.9 km/s.

HD 69830 is a yellow dwarf star located 41.0 light-years away in the constellation of Puppis. In 2005, the Spitzer Space Telescope discovered a narrow ring of warm debris orbiting the star. The debris ring contains substantially more dust than the Solar System's asteroid belt. In 2006, three extrasolar planets with minimum masses comparable to Neptune were confirmed in orbit around the star, located interior to the debris ring.

<span class="mw-page-title-main">HD 12039</span> Star in the constellation Cetus

HD 12039, also known as DK Ceti, is a variable star in the constellation of Cetus at a distance of 135 ly (41 pc). It is categorized as a BY Draconis variable because of luminosity changes caused by surface magnetic activity coupled with rotation of the star. The stellar classification G4V is similar to the Sun, indicating this is a main sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen. The effective temperature of 5,585 K gives the star a yellow hue. It has about the same mass as the Sun, but only emits 89% of the Sun's luminosity. This is a young star with age estimates ranging from 7.5−8 million years to 30 million years.

<span class="mw-page-title-main">Methods of detecting exoplanets</span>

Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported as of January 2024 have been observed directly, with even fewer being resolved from their host star.

<span class="mw-page-title-main">Debris disk</span> Disk of dust and debris in orbit around a star

A debris disk, or debris disc, is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris disks are found around stars with mature planetary systems, including at least one debris disk in orbit around an evolved neutron star. Debris disks can also be produced and maintained as the remnants of collisions between planetesimals, otherwise known as asteroids and comets.

<span class="mw-page-title-main">HD 141569</span> Star in the constellation Libra

HD 141569 is an isolated Herbig Ae/Be star of spectral class A2Ve approximately 364 light-years away in the constellation of Libra. The primary star has two red dwarf companions at about nine arcseconds. In 1999, a protoplanetary disk was discovered around the star. A gap in the disk led to speculation about a possible extrasolar planet forming in the disk.

<span class="mw-page-title-main">HR 8799</span> Star in the constellation Pegasus

HR 8799 is a roughly 30 million-year-old main-sequence star located 133.3 light-years away from Earth in the constellation of Pegasus. It has roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also contains a debris disk and at least four massive planets. Those planets, along with Fomalhaut b, were the first exoplanets whose orbital motion was confirmed by direct imaging. The star is a Gamma Doradus variable: its luminosity changes because of non-radial pulsations of its surface. The star is also classified as a Lambda Boötis star, which means its surface layers are depleted in iron peak elements. It is the only known star which is simultaneously a Gamma Doradus variable, a Lambda Boötis type, and a Vega-like star.

<span class="mw-page-title-main">Fomalhaut b</span> Extrasolar object orbiting Fomalhaut

Fomalhaut b, formally named Dagon, is a former candidate planet observed near the A-type main-sequence star Fomalhaut, approximately 25 light-years away in the constellation of Piscis Austrinus. The object's discovery was initially announced in 2008 and confirmed in 2012 via images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. Under the working hypothesis that the object was a planet, it was reported in January 2013 that it had a highly elliptical orbit with a period of 1,700 Earth years. The object was one of those selected by the International Astronomical Union as part of NameExoWorlds, their public process for giving proper names to exoplanets. The process involved public nomination and voting for the new name. In December 2015, the IAU announced the winning name was Dagon.

James R. Graham is an Irish astrophysicist who works primarily in the fields of infrared astronomy instrumentation and adaptive optics.

<span class="mw-page-title-main">Discoveries of exoplanets</span> Detecting planets located outside the Solar System

An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016; no planet discovery has yet come from that evidence. What turned out to be the first detection of an exoplanet was published among a list of possible candidates in 1988, though not confirmed until 2003. The first confirmed detection came in 1992, with the discovery of terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 24 July 2024, there are 7,026 confirmed exoplanets in 4,949 planetary systems, with 1007 systems having more than one planet. This is a list of the most notable discoveries.

<span class="mw-page-title-main">HD 139664</span> Star in the constellation Lupus

HD 139664 is a single star in the southern constellation of Lupus. It has the Bayer designation g Lupi; HD 139664 is the star's identifier from the Henry Draper Catalogue. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude of 4.64. The star is located at a distance of 57 light years from the Sun based on parallax, and it is drifting closer with a radial velocity of −7 km/s. It is a member of the Hercules-Lyra Association of co-moving stars.

HD 38858 is a G-type star, much like The Sun, with one detected planet. The planet, designated HD 38858 b, is about twice the mass of Uranus and orbits in the star's habitable zone.

<span class="mw-page-title-main">HD 115600</span> Star in the constellation Centaurus

HD 115600 is a star in the constellation Centaurus and a member of the Scorpius–Centaurus association, the nearest OB association to the Sun and the host star of a bright Kuiper belt-like debris ring.

References

  1. Overbye, Dennis (November 14, 2008). "First Pictures Taken of Extrasolar Planets". The New York Times . Retrieved 13 November 2008.
  2. Kalas, Paul; et al. (2008). "Optical Images of an Exosolar Planet 25 Light-Years from Earth". Science . 322 (5906): 1345–1348. arXiv: 0811.1994 . Bibcode:2008Sci...322.1345K. doi:10.1126/science.1166609. PMID   19008414. S2CID   10054103.
  3. "Paul Kalas – Astronomer | Author".
  4. Kalas, P.; Jewitt, D. (1995). "Asymmetries in the Beta Pictoris dust disk". The Astrophysical Journal . 110: 794–804. Bibcode:1995AJ....110..794K. doi:10.1086/117565.
  5. 1 2 Kalas, P.; Graham, J.R. & Clampin, M. (2005). "A planetary system as the origin of structure in Fomalhaut's dust belt". Nature . 435 (7045): 1067–1070. arXiv: astro-ph/0506574 . Bibcode:2005Natur.435.1067K. doi:10.1038/nature03601. PMID   15973402. S2CID   4406070.
  6. 1 2 Kalas, P.; Liu, M.C. & Matthews, B.C. (2004). "Discovery of a large dust disk around the nearby star AU Microscopii". Science . 303 (5666): 1990–1992. arXiv: astro-ph/0403132 . Bibcode:2004Sci...303.1990K. doi:10.1126/science.1093420. PMID   14988511. S2CID   6943137.
  7. Kalas, P.; Fitzgerald, M. & Graham, J.R. (2007). "Discovery of extreme asymmetry in the debris disk surrounding HD 15115". The Astrophysical Journal. 661 (1): L85–L88. arXiv: 0704.0645 . Bibcode:2007ApJ...661L..85K. doi:10.1086/518652. S2CID   16599464.
  8. 1 2 Kalas, P.; Graham, J.R.; Clampin, M.C. & Fitzgerald, M. (2006). "First scattered light images of debris disks around HD 53143 and HD 139664". The Astrophysical Journal. 637 (1): L57–L60. arXiv: astro-ph/0601488 . Bibcode:2006ApJ...637L..57K. doi:10.1086/500305. S2CID   18293244.
  9. Sarah Yang (November 24, 2014). "Four UC Berkeley faculty named AAAS fellows" . Retrieved 2015-11-16.
  10. AIAA Public Release (July 13, 2010). "Space 2010 Conference set for August 30 - Sep. 2 in Anaheim" . Retrieved 2015-11-16.
  11. Robert Sanders (February 18, 2010). "Images of extrasolar planets win award for most outstanding papers in Science" . Retrieved 2010-03-11.
  12. AAAS (November 2009). "Newcomb Cleveland Prize Recipients". Archived from the original on 2012-10-23. Retrieved 2010-04-21.