Solar radius

Solar radius is a unit of distance used to express the size of stars in astronomy equal to radius of the Sun. The solar radius is usually defined as the radius to the layer in the solar photosphere where the optical depth equals 2/3.:

The solar radius is approximately 695,700 kilometres (432,288 miles), which is about 10 times the average radius of Jupiter, 110 times the radius of the Earth, and 1/215th of an astronomical unit, the distance of Earth from the Sun. It varies slightly from pole to equator due to its rotation, which induces an oblateness of order 10 parts per million. (See 1 gigametre for similar distances.)

The SOHO spacecraft was used to measure the radius of the Sun by timing transits of Mercury across the surface during 2003 and 2006. The result was a measured radius of 696,342 ± 65 kilometres (432,687 ± 40 miles).

Haberreiter, Schmutz & Kosovichev (2008) determined the radius corresponding to the solar photosphere to be 695,660 ± 140 kilometres (432,263 ± 87 miles). This new value is consistent with helioseismic estimates, and the same study showed that previous estimates using inflection point methods had been overestimated by approximately 300 km.

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Latest News for: solar radii

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Unusual binary system hosts a massive fast-spinning white dwarf

Phys Dot Org 02 Jan 2025
According to the paper, the white dwarf emits pulsed X-rays with a very soft spectrum, powered by accretion from the stellar wind of the subdwarf, which has a radius of about 1.08 solar radii and its mass is around 1.41 solar masses.
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German astronomers discover three new hydrogen-deficient pre-white dwarfs

Phys Dot Org 31 Dec 2024
The star, which is located some 5,000 light years away, has an effective temperature of about 72,000 K and its mass is estimated to be 0.53 solar masses ... It has a radius of about 0.23 solar radii, while its mass is around 0.52 solar masses.
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Two Earth-sized exoplanets orbiting nearby star detected

Phys Dot Org 23 Dec 2024
When it comes to the host star, HD 101581, it is a K dwarf with a radius of about 0.63 solar radii and a mass of around 0.74 solar masses ... multiple transiting planets with radii below 1.5 Earth radii.
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Isro puts ESA’s Proba-3 in orbit; satellites to create solar eclipse experiment

The Times of India 05 Dec 2024
Solar scientists have ... Proba-3 will be able to create solar eclipses on demand, observing closer to the edge of the Sun than any previous Earth- or space-based instrument, down to just 1.1 solar radii.
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Spaceship that will block out Sun being launched

Atlantic News Telegraph 04 Dec 2024
... the solar corona ... Proba-3 will be able to create solar eclipses on demand, observing closer to the edge of the Sun than any previous Earth- or space-based instrument, down to just 1.1 solar radii.
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European twin satellites to create perfect artificial solar eclipse soon

Interesting Engineering 03 Dec 2024
... solar eclipses on demand ... The ESA mission team highlights that this mission will observe “closer to the edge of the Sun than any previous Earth- or space-based instrument, down to just 1.1 solar radii.
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CODEX Coronagraph Heads to the ISS on Cargo Dragon

Universe Today 08 Nov 2024
“Additionally, CODEX extends the measurements much closer to the Sun than Parker Solar Probe (PSP), linking the detailed measurements made at PSP at 10 solar radii through the middle corona, down to ~3 solar radii, closer to their source.
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Team discovers three new magnetic and helium-enriched hot subdwarf stars

Phys Dot Org 09 Oct 2024
... 0.74 and 0.56 solar masses, respectively. The study also found that all the three new He-sdOs have comparable radii (between 0.175 and 2.1 solar radii) and effective temperatures (46,000-47,680 K).
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What Is The Largest Star Ever Found – And The Most Massive?

IFL Science 01 Oct 2024
Despite the uncertainties in measurements, that probably puts it safely above WOH G64, estimated at 1,540 solar radii ... studies estimate the maximum theoretical radius for a star is 1,500 solar radii.
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NEID Earth Twin Survey discovers its first alien world

Phys Dot Org 26 Sep 2024
This is the first exoplanet detection made as part of the NEID Earth Twin Survey (NETS) ... Gupta of the U.S ... When it comes to the host star, HD 86728, it has a radius of approximately 1.24 solar radii, while its mass is comparable to that of the sun ... I.
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Observations provide crucial insights into the nature of a white dwarf–brown dwarf binary

Phys Dot Org 19 Sep 2024
According to the study, WD1032+011B has a radius of about 0.1 solar radii, which means that the object is inflated, likely due to the constant irradiation from the white dwarf.
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Groundbreaking New Maps of the Sun’s Coronal Magnetic Fields

Universe Today 12 Sep 2024
In an effort to understand space weather and the solar corona, the National Science Foundation aimed the world’s most powerful solar telescope, the Daniel K ... National Solar Observatory ... The black dotted lines show solar radii.
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New dense sub-Saturn exoplanet discovered

Phys Dot Org 10 Sep 2024
According to the study, TOI-6651 b has a radius of about 5.09 Earth radii, ... When it comes to the parent star, TOI-6651, it has a radius of about 1.32 solar radii, while its mass is 1.72 solar masses.
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New massive eccentric brown dwarf discovered

Phys Dot Org 14 Aug 2024
... Jupiter masses (0.012 and 0.076 solar masses) ... When it comes to the properties of the host star, TOI-2490, it is as massive as the sun, and its radius is measured to be approximately 1.1 solar radii.
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LAMOST J2354 binary hosts an unseen massive white dwarf, study suggests

Phys Dot Org 05 Aug 2024
The primary star is estimated to have a mass of about 0.7 solar masses, while the companion object is assumed to be a ... The orbital separation between the two objects was measured to be 3.3 solar radii.

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