Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Flame Photometry: Overview01:02

Flame Photometry: Overview

1.9K
Flame photometry, also known as flame emission spectrometry, is a technique used for the qualitative and quantitative analysis of elements present in a sample using a flame as the source of excitation energy. The concept of flame photometry was realized in the early 1860s by Kirchhoff and Bunsen, who discovered that specific elements emit characteristic radiation when excited in flames. The first instrument developed for this purpose was used to measure sodium (Na) in plant ash using a Bunsen...
1.9K
Flame Photometry: Lab01:16

Flame Photometry: Lab

1.2K
In a flame photometer, when a solution like potassium chloride is aspirated into the flame, the solvent evaporates, leaving behind dehydrated salt. This salt dissociates into free gaseous atoms in their ground state. Some of these atoms absorb energy from the flame, leading to their excitation. The excited atoms return to the ground state, emitting photons at characteristic wavelengths. Because only electronic transitions are involved, the resulting emission lines are very narrow. The intensity...
1.2K
Emission Spectra02:39

Emission Spectra

78.6K
When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a range of energies, and thereby produce a continuous spectrum in which an unbroken series of wavelengths is present.
78.6K
Nuclear Fusion02:45

Nuclear Fusion

35.1K
The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
35.1K
Fermi Level Dynamics01:12

Fermi Level Dynamics

976
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
976
Fermi Level01:18

Fermi Level

2.3K
The Fermi-Dirac function is represented by an S-shaped curve indicating the probability of an energy state being occupied by an electron at a given temperature. The Fermi level is the energy level at which there is a fifty percent chance of finding an electron, and it is positioned between the lower-energy valence band and the higher-energy conduction band.
At absolute zero temperature, electrons fill all energy states up to the Fermi level, leaving upper states empty. As the temperature rises,...
2.3K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Refractory Ventricular Fibrillation Associated With a Coronary Vasospasm and Fixed Moderate Coronary Stenosis.

JACC. Case reports·2026
Same author

Recurrence of cardiovascular events despite achieving LDL-C <1.4 mmol/L in patients with coronary artery disease.

Journal of clinical lipidology·2026
Same author

Synthesis and electrical characterization of rhenium-doped WS<sub>2</sub> nanotubes.

Nanoscale advances·2026
Same author

Lipoprotein(a) and residual cardiovascular risks in Japanese patients with coronary artery disease who achieve guideline-recommended low-density lipoprotein cholesterol goals.

European heart journal·2026
Same author

Understanding the cardiology training landscape in Asia-Pacific region.

Postgraduate medical journal·2026
Same author

Achieving LDL-C <1.0 mmol/L and cardiovascular outcomes in patients with coronary artery disease who received percutaneous coronary intervention.

Atherosclerosis·2026

Related Experiment Video

Updated: Mar 29, 2026

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
06:14

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface

Published on: July 30, 2020

5.5K

Superflares on solar-type stars.

Hiroyuki Maehara1, Takuya Shibayama, Shota Notsu

  • 1Kwasan and Hida Observatories, Kyoto University, 17 Ohmine-cho Kita Kazan, Yamashina-ku, Kyoto City, Kyoto 607-8471, Japan. maehara@kwasan.kyoto-u.ac.jp

Nature
|May 25, 2012
PubMed
Summary

Superflares, powerful stellar explosions, were observed on 365 stars, including solar-type stars with larger starspots. These events are more frequent on rapidly rotating stars but not directly linked to hot Jupiters.

More Related Videos

Surface Mapping of Earth-like Exoplanets using Single Point Light Curves
06:48

Surface Mapping of Earth-like Exoplanets using Single Point Light Curves

Published on: May 10, 2020

4.0K
Bringing the Visible Universe into Focus with Robo-AO
10:35

Bringing the Visible Universe into Focus with Robo-AO

Published on: February 12, 2013

20.3K

Related Experiment Videos

Last Updated: Mar 29, 2026

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
06:14

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface

Published on: July 30, 2020

5.5K
Surface Mapping of Earth-like Exoplanets using Single Point Light Curves
06:48

Surface Mapping of Earth-like Exoplanets using Single Point Light Curves

Published on: May 10, 2020

4.0K
Bringing the Visible Universe into Focus with Robo-AO
10:35

Bringing the Visible Universe into Focus with Robo-AO

Published on: February 12, 2013

20.3K

Area of Science:

  • * Astrophysics
  • * Stellar physics
  • * Exoplanet science

Background:

  • * Solar flares originate from the sudden release of magnetic energy near sunspots.
  • * Superflares, significantly more energetic than solar flares, have been observed on various stars, including rapidly rotating and solar-type stars.
  • * Previous studies of superflares on solar-type stars were limited due to their rarity.

Purpose of the Study:

  • * To investigate the characteristics and frequency of superflares on a large sample of stars, including solar-type stars.
  • * To explore the relationship between superflares, stellar rotation, starspot size, and the potential influence of hot Jupiter exoplanets.
  • * To analyze 365 superflares observed over 120 days across approximately 83,000 stars.

Main Methods:

  • * Photometric observations of ~83,000 stars over 120 days.
  • * Identification and analysis of 365 superflare events.
  • * Examination of quasi-periodic brightness modulations to infer starspot sizes.
  • * Correlation analysis between flare energy, stellar rotation period, and exoplanet presence.

Main Results:

  • * 365 superflares were observed, including events from slowly rotating solar-type stars.
  • * Solar-type stars exhibiting superflares showed evidence of significantly larger starspots than the Sun.
  • * Superflare maximum energy did not correlate with stellar rotation period, but frequency was higher for rapidly rotating stars.
  • * No hot Jupiter exoplanets were detected around the studied solar-type stars exhibiting superflares.

Conclusions:

  • * Superflares are a phenomenon observed across a range of stars, with characteristics influenced by stellar properties like rotation and starspot size.
  • * Rapid stellar rotation appears to increase superflare frequency, though not necessarily maximum energy.
  • * The absence of detected hot Jupiters suggests they are rare contributors to superflares on solar-type stars, challenging prior hypotheses.