Transiting planets in the galactic bulge from SWEEPS survey and implications

Kailash C. Sahu, Stefano Casertano, Jeff Valenti, Howard E. Bond, Thomas M. Brown, T. Ed Smith, Will Clarkson, Dante Minniti, Manuela Zoccali, Mario Livio, Alvio Renzini, R. M. Rich, Nino Panagia, Stephen Lubow, Timothy Brown, Nikolai Piskunov

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The SWEEPS (Sagittarius Window Eclipsing Extrasolar Planet Search) program was aimed at detecting planets around stars in the Galactic bulge, not only to determine their physical properties, but also to determine whether the properties of planets found in the solar neighborhood, such as their frequency and the metallicity dependence, also hold for the planets in the Galactic bulge. We used the Hubble Space Telescope to monitor 180,000 F, G, K, and M dwarfs in the Galactic bulge continuously for 7 days in order to look for transiting planets. We discovered 16 candidate transiting extrasolar planets with periods of 0.6 to 4.2 days, including a possible new class of ultra-short period planets (USPPs) with P < 1 day. The facts that (i) the coverage in the monitoring program is continuous, (ii) most of the stars are at a known distance (in the Galctic bulge), (iii) monitoring was carried out in 2 passbands, and (iv) the images have high spatial resolution, were crucial in minimizing and estimating the false positive rates. We estimate that at least 45% of the candidates are genuine planets. Radial velocity observations of the two brightest host stars further support the planetary nature of the transiting companions. These results suggest that the planet frequency in the Galactic bulge is similar to that in the solar neighborhood. They also suggest that higher metallicity favors planet formation even in the Galactic bulge. The USPPs occur only around low-mass stars which may suggest that close-in planets around higher-mass stars are irradiately evaporated, or that planets are able to migrate to and survive in close-in orbits only around such old and low-mass stars.

Original languageEnglish (US)
Pages (from-to)45-53
Number of pages9
JournalProceedings of the International Astronomical Union
Volume4
Issue numberS253
DOIs
StatePublished - May 1 2008

Fingerprint

galactic bulge
extrasolar planets
planets
planet
stars
solar neighborhood
metallicity
Hubble Space Telescope
radial velocity
monitoring
estimating
physical properties
spatial resolution

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics

Cite this

Sahu, Kailash C. ; Casertano, Stefano ; Valenti, Jeff ; Bond, Howard E. ; Brown, Thomas M. ; Ed Smith, T. ; Clarkson, Will ; Minniti, Dante ; Zoccali, Manuela ; Livio, Mario ; Renzini, Alvio ; Rich, R. M. ; Panagia, Nino ; Lubow, Stephen ; Brown, Timothy ; Piskunov, Nikolai. / Transiting planets in the galactic bulge from SWEEPS survey and implications. In: Proceedings of the International Astronomical Union. 2008 ; Vol. 4, No. S253. pp. 45-53.
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abstract = "The SWEEPS (Sagittarius Window Eclipsing Extrasolar Planet Search) program was aimed at detecting planets around stars in the Galactic bulge, not only to determine their physical properties, but also to determine whether the properties of planets found in the solar neighborhood, such as their frequency and the metallicity dependence, also hold for the planets in the Galactic bulge. We used the Hubble Space Telescope to monitor 180,000 F, G, K, and M dwarfs in the Galactic bulge continuously for 7 days in order to look for transiting planets. We discovered 16 candidate transiting extrasolar planets with periods of 0.6 to 4.2 days, including a possible new class of ultra-short period planets (USPPs) with P < 1 day. The facts that (i) the coverage in the monitoring program is continuous, (ii) most of the stars are at a known distance (in the Galctic bulge), (iii) monitoring was carried out in 2 passbands, and (iv) the images have high spatial resolution, were crucial in minimizing and estimating the false positive rates. We estimate that at least 45{\%} of the candidates are genuine planets. Radial velocity observations of the two brightest host stars further support the planetary nature of the transiting companions. These results suggest that the planet frequency in the Galactic bulge is similar to that in the solar neighborhood. They also suggest that higher metallicity favors planet formation even in the Galactic bulge. The USPPs occur only around low-mass stars which may suggest that close-in planets around higher-mass stars are irradiately evaporated, or that planets are able to migrate to and survive in close-in orbits only around such old and low-mass stars.",
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Sahu, KC, Casertano, S, Valenti, J, Bond, HE, Brown, TM, Ed Smith, T, Clarkson, W, Minniti, D, Zoccali, M, Livio, M, Renzini, A, Rich, RM, Panagia, N, Lubow, S, Brown, T & Piskunov, N 2008, 'Transiting planets in the galactic bulge from SWEEPS survey and implications', Proceedings of the International Astronomical Union, vol. 4, no. S253, pp. 45-53. https://doi.org/10.1017/S1743921308026227

Transiting planets in the galactic bulge from SWEEPS survey and implications. / Sahu, Kailash C.; Casertano, Stefano; Valenti, Jeff; Bond, Howard E.; Brown, Thomas M.; Ed Smith, T.; Clarkson, Will; Minniti, Dante; Zoccali, Manuela; Livio, Mario; Renzini, Alvio; Rich, R. M.; Panagia, Nino; Lubow, Stephen; Brown, Timothy; Piskunov, Nikolai.

In: Proceedings of the International Astronomical Union, Vol. 4, No. S253, 01.05.2008, p. 45-53.

Research output: Contribution to journalArticle

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T1 - Transiting planets in the galactic bulge from SWEEPS survey and implications

AU - Sahu, Kailash C.

AU - Casertano, Stefano

AU - Valenti, Jeff

AU - Bond, Howard E.

AU - Brown, Thomas M.

AU - Ed Smith, T.

AU - Clarkson, Will

AU - Minniti, Dante

AU - Zoccali, Manuela

AU - Livio, Mario

AU - Renzini, Alvio

AU - Rich, R. M.

AU - Panagia, Nino

AU - Lubow, Stephen

AU - Brown, Timothy

AU - Piskunov, Nikolai

PY - 2008/5/1

Y1 - 2008/5/1

N2 - The SWEEPS (Sagittarius Window Eclipsing Extrasolar Planet Search) program was aimed at detecting planets around stars in the Galactic bulge, not only to determine their physical properties, but also to determine whether the properties of planets found in the solar neighborhood, such as their frequency and the metallicity dependence, also hold for the planets in the Galactic bulge. We used the Hubble Space Telescope to monitor 180,000 F, G, K, and M dwarfs in the Galactic bulge continuously for 7 days in order to look for transiting planets. We discovered 16 candidate transiting extrasolar planets with periods of 0.6 to 4.2 days, including a possible new class of ultra-short period planets (USPPs) with P < 1 day. The facts that (i) the coverage in the monitoring program is continuous, (ii) most of the stars are at a known distance (in the Galctic bulge), (iii) monitoring was carried out in 2 passbands, and (iv) the images have high spatial resolution, were crucial in minimizing and estimating the false positive rates. We estimate that at least 45% of the candidates are genuine planets. Radial velocity observations of the two brightest host stars further support the planetary nature of the transiting companions. These results suggest that the planet frequency in the Galactic bulge is similar to that in the solar neighborhood. They also suggest that higher metallicity favors planet formation even in the Galactic bulge. The USPPs occur only around low-mass stars which may suggest that close-in planets around higher-mass stars are irradiately evaporated, or that planets are able to migrate to and survive in close-in orbits only around such old and low-mass stars.

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