Hubble telescope findings
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Hubble Space Telescope Findings
Measurement of the Hubble Constant
Precision Calibration Using Cepheid Variables and Type Ia Supernovae
The Hubble Space Telescope (HST) has significantly refined the measurement of the Hubble constant (H₀) through observations of Cepheid variables in the host galaxies of 42 Type Ia supernovae (SNe Ia). These observations, calibrated using Gaia EDR3 parallaxes, masers in NGC 4258, and detached eclipsing binaries in the Large Magellanic Cloud, have reduced the uncertainty in the local determination of H₀ to 1 km s⁻¹ Mpc⁻¹. The baseline result from this comprehensive study is H₀ = 73.04 ± 1.04 km s⁻¹ Mpc⁻¹, which is consistent across various analysis variants and shows a significant discrepancy with the H₀ value predicted by Planck cosmic microwave background observations under the ΛCDM model1.
Alternative Calibration Using Mira Variables
In addition to Cepheid variables, HST has explored the use of Mira variables for calibrating the Hubble constant. Observations of Mira variables in the SN Ia host galaxy NGC 1559 have provided a new calibration method, yielding a Hubble constant value of H₀ = 73.3 ± 1.04 km s⁻¹ Mpc⁻¹. This method offers a promising alternative to Cepheid-based calibrations and could help resolve the current tension in H₀ measurements4.
Discoveries in Exoplanetary Atmospheres
High-Altitude Atmospheric Haze on HD 189733b
HST's transmission spectroscopy of the exoplanet HD 189733b has revealed the presence of high-altitude atmospheric haze. The optical and near-ultraviolet spectra indicate Rayleigh scattering, suggesting that the haze covers the entire optical regime. This finding enhances our understanding of exoplanetary atmospheres and their compositions, indicating that such hazes may be a common feature in hot Jupiters3.
Insights into Early Universe Galaxies
Bright Lyman-Break Galaxies at Redshift z ~ 7
HST imaging of 25 extremely luminous Lyman-break galaxies (LBGs) at redshift z ≈ 7 has provided valuable insights into the nature of these early universe galaxies. The observations suggest that these galaxies often exhibit irregular, clumpy, or merging morphologies. Additionally, the presence of strong rest-frame optical nebular emission lines indicates active star formation processes. These findings contribute to our understanding of galaxy formation and evolution in the early universe2.
Stellar and Galactic Phenomena
Evolution of AT 2018cow
HST has monitored the evolution of the UV-bright source at the position of AT 2018cow, revealing significant changes over 2-4 years post-discovery. The observations suggest a highly inclined precessing accretion disk as a plausible explanation for the observed color and brightness variations. This study provides critical data for understanding the nature of transient astronomical events and their underlying mechanisms5.
Starburst Galaxy M82
HST's Advanced Camera for Surveys has captured detailed mosaic images of the starburst galaxy M82, revealing intricate structures and star-forming regions. These high-resolution images have been instrumental in studying the dynamics and composition of starburst galaxies, offering a deeper understanding of their role in galactic evolution8.
Conclusion
The Hubble Space Telescope continues to be a cornerstone of astronomical research, providing precise measurements and groundbreaking discoveries across various fields. From refining the Hubble constant to unveiling the complexities of exoplanetary atmospheres and early universe galaxies, HST's contributions are invaluable in advancing our knowledge of the cosmos.
Sources and full results
Most relevant research papers on this topic
A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km s−1 Mpc−1 Uncertainty from the Hubble Space Telescope and the SH0ES Team
The Hubble constant (H 0) is 73.04 1.04 km s1 Mpc1 with systematic uncertainties, a 5 difference from Planck cosmic microwave background predictions under CDM.
Highly CitedUnveiling the nature of bright z ~ 7 galaxies with the Hubble Space Telescope
New Hubble Space Telescope imaging reveals that most extremely luminous Lyman-break galaxies at z 7 will be spatially resolved by Euclid, mitigating concerns over dwarf star contamination.
Highly CitedHubble Space Telescope transmission spectroscopy of the exoplanet HD 189733b: high‐altitude atmospheric haze in the optical and near‐ultraviolet with STIS
High-altitude atmospheric haze may be a globally dominant feature on HD 189733b, resulting in a high optical albedo at shorter wavelengths.
Highly CitedHubble Space Telescope Observations of Mira Variables in the SN Ia Host NGC 1559: An Alternative Candle to Measure the Hubble Constant
Mira variables in NGC 1559 can effectively calibrate the Hubble constant, reducing the error in H0 by 3%.
Highly Cited