Sagittarius Window Eclipsing Extrasolar Planet Search

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Sagittarius Window Eclipsing Extrasolar Planet Search
HST SWEEPS Detail 2006.jpg
Detail image with exoplanet locations indicated with green circles.
Organization NASA / ESA / STSci
Alternative names SWEEPS
Wavelength 350-1100 nm
Data sources Hubble Space Telescope Advanced Camera for Surveys - Wide Field Channel
Goals Search for exoplanets in the Milky Way's central bulge
Data products 16 candidate planets (Nos 1-16) are found around 16 stars (format JHHMMSS.ss+DDMMSS.s)[1]

The Sagittarius Window Eclipsing Extrasolar Planet Search, or SWEEPS, was a 2006 astronomical survey project using the Hubble Space Telescope's Advanced Camera for Surveys - Wide Field Channel to monitor 180,000 stars for seven days to detect extrasolar planets via the transit method.[1]

Area examined[edit]

SWEEPS search area.
SWEEPS search area detail.

The stars that were monitored in this astronomical survey were all located in the Sagittarius-I Window, a rare transparent view to the Milky Way's central bulge stars in the Sagittarius constellation as our view to most of the galaxy's central stars is blocked by lanes of dust. These stars in the galaxy's central bulge region are approximately 27,000 light years from Earth.[2]

Planets discovered[edit]

Sixteen candidate planets were discovered with orbital periods ranging from 0.6 to 4.2 days. Planets with orbital periods less than 1.2 days have not previously been detected, and have been dubbed "ultra-short period planets" (USPPs) by the search team. USPPs were discovered only around low-mass stars, suggesting that larger stars destroyed any planets orbiting so closely or that planets were unable to migrate as far inward around larger stars.[3]

Planets were found with roughly the same frequency of occurrence as in the local neighborhood of Earth.[2]

SWEEPS-4 and SWEEPS-11 orbited stars that were sufficiently visually distinct from their neighbors that follow-up observations using the radial velocity method were possible, allowing their masses to be determined.[2]

This table is constructed from information obtained from the Extrasolar Planets Encyclopedia and SIMBAD databases that reference the Nature article as their source.[3]

Star Constellation Right
ascension
Declination App.
mag.
Distance (ly) Spectral
type
Planet Mass
(MJ)
Radius
(RJ)
Orbital
period

(d)
Semimajor
axis

(AU)
Orbital
eccentricity
Inclination
(°)
Discovery
year
SWEEPS J175853.29-291233.5 Sagittarius 17h 58m 53s −29° 12′ 33″ 22.2 ~22000 SWEEPS-01  ? 1.01 1.56 0.025  ? 86+ 2006
SWEEPS J175853.38-291217.8 Sagittarius 17h 58m 53s −29° 12′ 18″ 25.1 ~22000 SWEEPS-02  ? 1.37 0.912 0.015  ? 86+ 2006
SWEEPS J175853.57-291144.1 Sagittarius 17h 58m 53s −29° 11′ 44″ 22.5 ~22000 SWEEPS-03  ? 0.87 1.27 0.021  ? 86+ 2006
SWEEPS J175853.92−291120.6 Sagittarius 17h 58m 54s −29° 11′ 21″ 18.8 ~22000 SWEEPS-04 <3.8 0.81 4.2 0.055  ? 87+ 2006
SWEEPS J175854.60-291128.2 Sagittarius 17h 58m 55s −29° 11′ 28″ 23.9 ~22000 SWEEPS-05  ? 1.09 2.313 0.030  ? 87+ 2006
SWEEPS J175857.29-291253.4 Sagittarius 17h 58m 57s −29° 12′ 53″ 19.5 ~22000 SWEEPS-06  ? 0.82 3.039 0.042  ? 86+ 2006
SWEEPS J175857.69-291114.5 Sagittarius 17h 58m 58s −29° 11′ 15″ 21.5 ~22000 SWEEPS-07  ? 0.9 1.747 0.027  ? 86+ 2006
SWEEPS J175859.24-291328.7 Sagittarius 17h 58m 59s −29° 13′ 29″ 21.7 ~22000 SWEEPS-08  ? 0.98 0.868 0.017  ? 84+ 2006
SWEEPS J175859.60-291211.8 Sagittarius 17h 59m 00s −29° 12′ 12″ 22.5 ~22000 SWEEPS-09  ? 1.01 1.617 0.025  ? 86+ 2006
SWEEPS J175902.00-291323.7 Sagittarius 17h 59m 02s −29° 13′ 24″ 26.2 ~22000 SWEEPS-10  ? 1.24 0.424 0.008  ? 84+ 2006
SWEEPS J175902.67−291153.5 Sagittarius 17h 59m 03s −29° 11′ 54″ 19.83 ~22000 SWEEPS-11 9.7 1.13 1.796 0.03  ? 84+ 2006
SWEEPS J175904.44-291317.1 Sagittarius 17h 59m 04s −29° 13′ 17″ 21.8 ~22000 SWEEPS-12  ? 0.91 2.952 0.038  ? 87+ 2006
SWEEPS J175905.95-291305.6 Sagittarius 17h 59m 04s −29° 13′ 17″ 21.38 ~22000 SWEEPS-13  ? 0.78 1.684 0.027  ? 86+ 2006
SWEEPS J175907.56-291039.8 Sagittarius 17h 59m 04s −29° 13′ 17″ 22.38 ~22000 SWEEPS-14  ? 0.93 2.965 0.037  ? 87+ 2006
SWEEPS J175907.64-291023.7 Sagittarius 17h 59m 04s −29° 13′ 17″ 25.66 ~22000 SWEEPS-15  ? 1.37 0.541 0.010  ? 84+ 2006
SWEEPS J175908.44-291140.6 Sagittarius 17h 59m 08s −29° 11′ 41″ 23.78 ~22000 SWEEPS-16  ? 1.4 0.969 0.017  ? 85+ 2006

See also[edit]

References[edit]

  1. ^ a b "SIMBAD Details on Acronym: SWEEPS". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2009-05-21. 
  2. ^ a b c Sahu, K. C.; et al. (2007). "Planets in the Galactic Bulge: Results from the SWEEPS Project". ASP Conference Series 393: 93. arXiv:0711.4059. Bibcode:2008ASPC..398...93S. 
  3. ^ a b Sahu, K. C.; et al. (2006). "Transiting extrasolar planetary candidates in the Galactic bulge". Nature 443 (7111): 534–540. arXiv:astro-ph/0610098. Bibcode:2006Natur.443..534S. doi:10.1038/nature05158. PMID 17024085. 

External links[edit]