astronomy

SDSS J230641.47+244055.8

SDSS J230641.47+244055.8 is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand SDSS J230641.47+244055.8 rather than just read about it. In short: SDSS J230641.47+244055.8 (abbreviated as SDSS J2306) is a binary star system composed of a pulsar-like white dwarf and a red dwarf, located in the constellation Pegasus at a distance of approximately 4,000 light-years. This is the third such system discovered, following AR Scorpii and eRASSU J191213.9-441044.

Key takeaways

SDSS J230641.47+244055.8 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect SDSS J230641.47+244055.8 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of SDSS J230641.47+244055.8 from memory before moving on to harder problems.

Reference excerpt

SDSS J230641.47+244055.8 (abbreviated as SDSS J2306) is a binary star system composed of a pulsar-like white dwarf and a red dwarf, located in the constellation Pegasus at a distance of approximately 4,000 light-years. This is the third such system discovered, following AR Scorpii and eRASSU J191213.9-441044.

Discovery In 2020, a team of astronomers led by Chen was analyzing data from the Zwicky Transient Facility (ZTF) photometric survey. The object SDSS J2306 was mistakenly classified as an W Ursae Majoris-type contact binary with a presumed orbital period of 6.98794 hours. In 2023, a group of scientists headed by Inayath studied the object's spectrum, obtained as part of the Sloan Digital Sky Survey (SDSS). They ruled out eclipses, instead describing light variations due to the heated side of the red dwarf as it orbits and rotates, as well as more rapid intrinsic variations. The spectrum is dominated by molecular bands from the cool M-type red dwarf, but with peculiar bright hydrogen emission lines present. There is also pulsed emission across the whole electromagnetic spectrum. In the summer of 2025, an international research team, during a targeted search for analogs of the AR Scorpii system, re-examined the object's archival spectral data and discovered features characteristic of white dwarf pulsars. Subsequent high-precision photometric observations confirmed the system's true orbital period of 3.49 hours and recorded stable pulsations with a period of 92 seconds, attributed to the white dwarfs rotation. As a result, the object was officially registered as the third known white dwarf pulsar.

Characteristics The system consists of two stars orbiting a common center of mass with an orbital period of 3.49 hours. The primary star is a rapidly rotating white dwarf. Due to its strong magnetic field and high rotation speed with a period of 92.28 seconds, the star generates beamed non-thermal radiation. This rotation period is the second fastest among known pulsars of this type, surpassed only by eRASSU J191213.9-441044. The companion star is a low-mass red dwarf of spectral type M4.0±0.5. Its mass is estimated to be in the range of 0.19 - 0.28 M☉, and its effective temperature is 3300 K. The star almost completely fills its Roche lobe, and its atmosphere is continuously subjected to intense irradiation from the white dwarf.

Variability The system's optical light curve, plotted against its orbital period, shows a significant brightness scatter of up to 10%. The most powerful fluctuations and chaotic flares occur at those moments when the tidally locked, irradiated side of the red dwarf faces Earth. The system's integrated luminosity noticeably exceeds the combined thermal radiation of both stars, which is due to the transformation of the white dwarf's rotational kinetic energy into radiation. The optical spectra of the system simultaneously exhibit signs of both components. In the red and infrared regions, broad molecular absorption bands of titanium oxide (TiO) and absorption lines of sodium (Na I), characteristic of M-dwarf atmospheres, dominate. Against the background of the continuum spectrum, narrow emission lines of the Balmer series of hydrogen (Hα) and neutral helium (He I) are observed, generated by photoionization of the upper layers of the companion's atmosphere. The Hα line also has a broad, low-amplitude component, indicating energetic flare processes.

References

Worked examples

Example 1 — a first encounter with SDSS J230641.47+244055.8

Start with the simplest possible case. Write down what SDSS J230641.47+244055.8 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to SDSS J230641.47+244055.8 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about SDSS J230641.47+244055.8 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of SDSS J230641.47+244055.8

In research: SDSS J230641.47+244055.8 appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses SDSS J230641.47+244055.8 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: SDSS J230641.47+244055.8 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Binary stars, M-type main-sequence stars, Pegasus (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for SDSS J230641.47+244055.8 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study SDSS J230641.47+244055.8 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what SDSS J230641.47+244055.8 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
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Frequently asked questions

What is SDSS J230641.47+244055.8 in simple terms?

Why does SDSS J230641.47+244055.8 matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study SDSS J230641.47+244055.8?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on SDSS J230641.47+244055.8.