<ol>
<li><p>As you said, the mass range of the object indicates that it could be a neutron star, rather than a black hole.</p></li>
<li><p>But also the density of the object is a clue. The density of a neutron star is much higher than that of a stable white dwarf.</p></li>
<li><p>Extremely regular electromagnetic pulses have to be observed. Known pulsars have a pulse period between 1.4 ms and 8.5 seconds. </p></li>
<li><p>The wavelength of the pulses is in the radio range.</p></li>
<li><p>Pulsars slow down gradually, at a known rate, so you can measure how the pulse period evolves over time, and check that is compatible with the slow-down rate of a pulsar.</p></li>
</ol>

<p>Adapted from <a href="https://www.cv.nrao.edu/course/astr534/Pulsars.html" rel="nofollow noreferrer">this page</a></p>

CC BY-SA 4.0
2020-05-05T14:56:43.547Z
2020-05-05T14:56:43.547Z
usernumber
<blockquote>
  <p>We have a star having 1.8 solar mass. Justify any four means (measurable/ observed properties) by which you can identify that the object is a Pulsar and not a white dwarf or a Black Hole.</p>
</blockquote>

<p>So one obvious property would be the mass. Since mass > 1.4 solar mass, we can say it is not a white dwarf. </p>

<p>Also the mass is less than 3 solar mass, hence its not a black hole (I'm speaking loosely over here). </p>

<p>Also from periodic radiation patterns, we can say that the object might be a pulsar. </p>

<p>I need help with 2 other means to categorize this object.</p>

CC BY-SA 4.0
2020-04-29T02:05:24.730Z
Being a homework question is neither bad nor good, we could recommend how the question could be improved though. Also see [Make no prior research or effort a reason to close?](https://astronomy.meta.stackexchange.com/q/428/7982)
uhoh
CC BY-SA 4.0
2020-04-29T07:44:28.287Z
Please note that many students are being asked to do "at home", uninvigilated exams right now. Please do not answer such questions.
ProfRob
CC BY-SA 4.0
2020-04-29T07:46:34.703Z
This is not an exam, just some assignment, and I am not a school going kid.
sanchit krishna
<black-hole><neutron-star><white-dwarf>
Is the object a pulsar
sanchit krishna
# Is the object a pulsar

(Asked by: username_0 on 2020-04-29)

> We have a star having 1.8 solar mass. Justify any four means (measurable/ observed properties) by which you can identify that the object is a Pulsar and not a white dwarf or a Black Hole.

So one obvious property would be the mass. Since mass > 1.4 solar mass, we can say it is not a white dwarf.

Also the mass is less than 3 solar mass, hence its not a black hole (I'm speaking loosely over here).

Also from periodic radiation patterns, we can say that the object might be a pulsar.

I need help with 2 other means to categorize this object.

**Tags:** black-hole, neutron-star, white-dwarf

> **Comments:**
> **username_1**: Being a homework question is neither bad nor good, we could recommend how the question could be improved though. Also see [Make no prior research or effort a reason to close?](https://astronomy.meta.stackexchange.com/q/428/7982)  
> **username_2**: Please note that many students are being asked to do "at home", uninvigilated exams right now. Please do not answer such questions.  
> **username_0**: This is not an exam, just some assignment, and I am not a school going kid.  

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## 1 answers

### Answer by username_3 on 2020-05-05. Score: 1

1. As you said, the mass range of the object indicates that it could be a neutron star, rather than a black hole.
2. But also the density of the object is a clue. The density of a neutron star is much higher than that of a stable white dwarf.
3. Extremely regular electromagnetic pulses have to be observed. Known pulsars have a pulse period between 1.4 ms and 8.5 seconds.
4. The wavelength of the pulses is in the radio range.
5. Pulsars slow down gradually, at a known rate, so you can measure how the pulse period evolves over time, and check that is compatible with the slow-down rate of a pulsar.

Adapted from [this page](https://www.cv.nrao.edu/course/astr534/Pulsars.html)


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